SOLAR ENERGY
FOR
PACIFIC NORTHWEST
RESIDENTIAL HEATING
MAY 1978
U.S. D.O.E.
SEATTLE
U.S. D.O.E.
RICHLAND
U.S. E.P.A.
SEATTLE

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SOLAR ENERGY
FOR PACIFIC NORTHWEST RESIDENTIAL HEATING
An Interagency
Report by
The U.S. Department of Energy
Region X Office of the
Regional Representative
The U.S. Department of Energy
Richland, Washington Operations
Office, and
The U.S. Environmental Protection
Agency, Region X Office
May 1978

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SOLAR ENERGY
FOR PACIFIC NORTHWEST RESIDENTIAL HEATING
Submitted by
95* m.
Tei
I'erry M. Dolan, P.E.
U.S. Department of Energy, Region X
Project Manager
/
/
i(U\ /.( /	1-n IV,
Steven W. Anderson
U.S. Department of Energy, Region X
Assistant Regional Counsel
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TABLE OF CONTENTS
CHAPTER	PAGE
I	INTRODUCTION AND SUMMARY
Introduction 		1-1
Overview		1-1
Major Conclusions		1-5
II	AVAILABLE SOLAR ENERGY IN THE PACIFIC NORTHWEST
Introducticn 		II-l
Solar Energy on a Horizontal Surface	II-2
Direct and Diffuse Components of Insolation. . .	II-7
Available Solar Energy on South-Facing
Collectors	11-12
Northwest Weather	11-20
Conclusions	11-22
References	H-25
III	TECHNOLOGY AND ECONOMIC ANALYSIS
Introduction 		III-l
Solar Systems	III-l
Active System Analysis 		111-23
Conclusions	111-58
References 		111-59
IV	THE IMPACT OF WIDESPREAD SOLAR DEVELOPMENTS ON
ENERGY SUPPLY UTILITIES AND HEATING FUEL DEALERS
Introduction 		IV-1
Heating Oil Impacts	IV-4
Natural Gas Impacts	IV-5
Electricity Impacts	IV-15
Rate Structures	IV-24
Conclusions	IV-28
References	IV-30
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V LEGAL ISSUES AFFECTING SOLAR ENERGY DEVELOPMENT
Introduction 		V-l
Right to Light		V-l
Easement		V-2
Restrictive Covenance		V-5
Nuisance		V-7
Public Law Doctrines: Building Codes and
Zoning		V-9
Zoning		V-13
Zoning and Eminent Domain		V-l4
Transferable Development Rights		V-l8
Developments in Zoning Law		V-l9
Solar Skyspace Easement				V-21
Other Developments		V-22
Comprehensive Land Use Planning		V-24
Conclusions and Recommendations		V-25
References		V-28
VI ENVIRONMENTAL CONSIDERATIONS
Introduction 		VI-1
Quantitative Analysis of Fuel Use and Air
Emissions	VI-2
Outgassing	VI-12
Disposal of Heat Transfer Fluids 		VI-13
Solid Waste	VI-14
Health and Safety	VI-16
Land Use	VI-2 3
Air Pollution Effects on Insolation in the
Northwest	VI-25
Conclusions	VI-28
References	Vl-31
APPENDIX A Current Solar Heating and Cooling
Research in the Pacific Northwest
APPENDIX B
Glossary of Terms and Abbreviations
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CHAPTER I
Introduction and Summary
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Introduction
This report examines climatic, technical, economic, legal,
institutional, and environmental issues related to development
of solar energy as a resource for residential space and
water heating applications in the Pacific Northwest.* It
provides objective information to the public concerning the
opportunities for and impediments to widespread solar development.
Industrial uses and generation of electricity from solar
power are not included in this report. The following is a
summary of the contents of each chapter and the conclusions
of the report.
Summary
AVAILABLE SOLAR ENERGY IN THE PACIFIC NORTHWEST, CHAPTER II
This chapter provides objective data, quantifying the amount
of solar radiation available for Northwest heating and
cooling, in a manner that would be useful for someone designing
a solar heating or cooling system.
Throughout this report, "Pacific Northwest" and
"Northwest" are used to indicate the geographical
area comprising the states of Washington, Oregon,
and Idaho.
1-1
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TECHNOLOGY AND ECONOMIC ANALYSIS, CHAPTER III
This chapter examines the economic feasibility of residential
solar space and water heating in the Northwest, taking into
account the climatic conditions discussed in Chapter II and
the cost of conventional heating energy sources (oil, gas,
and electricity). It describes active and passive systems
as well as solar/heat pump cycles and discusses the benefits
and liabilities of each system type. Economic analyses of
active systems are presented for the 12 Northwest locations
where comprehensive and reliable insolation data are available
The analyses are based on FCHART, a computerized design
tool developed by the University of Wisconsin. The results
are displayed as curves relating system cost and the cost of
electricity to the "years-to-break-even." The chapter also
includes a sensitivity analysis of the variables affecting
solar economics.
IMPACT OF WIDESPREAD SOLAR DEVELOPMENT ON ENERGY SUPPLY
UTILITIES AND OIL FUEL DEALERS, CHAPTER IV
This chapter examines some of the consequences of "widespread
solar development" as they relate to the three major sources
of conventional heating energy 	 gas, oil, and electricity.
It also discusses how utility rate structures affect, and
are affected by, solar space and water heating development.
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LEGAL ISSUES AFFECTING SOLAR ENERGY DEVELOPMENT, CHAPTER V
This Chapter examines various private and public law doctrines
which may affect a solar user's right to sunlight, points
out obstacles to the widespread use of solar energy, and
suggests changes which will accommodate and encourage solar
energy use.
ENVIRONMENTAL CONSIDERATIONS, CHAPTER VI
This chapter examines potential air, water, solid waste, and
health impacts of widespread solar development. Both positive
effects (reduced air and water emissions from conventional
energy sources), and negative effects (disposal of toxic
fluids, increased glare, potential contamination of potable
water systems), are discussed. It also describes the effect
of air pollution on the availability of solar energy.
The references cited in each chapter are listed at the
conclusion of that chapter. Appendix A is a listing of
current Northwest solar research projects; Appendix B is a
glossary of technical terms and abbreviations.
Major Conclusions
Based only on climatic factors, the attractiveness of
1-3
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solar space heating, as measured by the Solar Heating
Index,* is relatively uniform throughout the Northwest.
This uniformity is due to two related conditions. West
of the Cascade Mountains, it is cloudier, but more
temperate; east of the Cascades, there is more available
solar radiation, but the winters are colder. These
conditions roughly balance each other. The Richland/
Prosser area of Washington and the Medford, Oregon area
appear to be the most attractive areas for solar heating
applications.
- Based on climatic factors, the attractiveness of solar
space heating, is better for all Northwest locations
studied than for a variety of other representative
Northern locations surveyed: Chicago, Illinois;
Madison, Wisconsin; Schenectady, New York; and Great
Falls, Montana.
Based on a consideration of available solar radiation,
solar water heating, which is not usually affected by
outside air temperatures, appears to be more attractive
in clear-sky eastern portions of the region.
The Solar Heating Index is defined in Chapter II as the
amount of solar energy received on a horizontal surface
divided by the number of heating degree days.
1-4
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Solar collection in Northwest latitudes is improved
significantly during winter months by tilting collector
surfaces 45° to 60° above horizontal, facing south.
Available solar energy on such inclined south-facing
surfaces is approximately twice that of horizontal
surfaces during November, December, and January. See
Table II-2 for detailed data.
TECHNICAL AND ECONOMIC ANALYSIS
Passive solar heating can often be integrated into new
buildings as part of the architecture at very little
additional cost. According to a University of Oregon
study, some passive systems can meet 60 to 70 percent
of a residence's space heating needs in the Northwest.
This is the most cost effective application of solar
heating.
Currently, the most cost effective residential application
of active solar heating in the Northwest is a swimming
pool heater. Typical "years-to-break-even" periods for
solar swimming pool heaters are less than ten years.
Currently, in the Pacific Northwest, active solar space
and water heating systems are less cost effective than
other solar applications. Typical payback periods for
1-5
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active solar space and water heaters are longer than
ten years.
The solar/heat pump combined cycle studied by the
Northwest Energy Policy Project group has typical
"years-to-break-even" periods longer than 15 years in
the Northwest.
IMPACT ON UTILITIES
The widespread development of residential solar space
and water heating would tend to lower overall consumption
of conventional energy sources (oil, gas, and electricity)
and, thus, save energy. However, it appears that such
a conversion to solar heating would neither substantially
reduce overall utility load factors* nor the utilities'
ability to provide adequate service to the public.
"Demand/energy" utility rate structures** have been
adopted in some areas and may act to discourage solar
"Load factor" is the ratio of average load carried by
an electric or gas utility to its peak load. A low (or
"poor") load factor means that a utility has high peaks
relative to its average load and this results in inherent
inefficiencies.
** "Demand/energy" rate structures base the charge for
electrical service on both the total kilowatt-hours
used (energy), and the maximum electrical load (demand)
during any 15 minute period during the billing period.
1-6
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development because large reductions in energy consumption
do not result in proportional reductions in energy
costs. Hence, savings may not be sufficiently attractive
economically to justify the often large capital investment
required for solar systems.
LEGAL ASPECTS
In general, present law does not adequately protect
access to sunlight for users of solar energy.
Under present law, restrictive covenants can be a
primary method for protecting access to sunlight for
new real estate developments. However, restrictive
covenants do not usually provide adequate protection
for solar energy users in areas that are already developed.
The adoption of a "solar skyspace easement" law, under
which easements negotiated between private parties
could be recorded in a standard format, would appear to
offer improved legal protection for many solar energy
users in developed areas.
The use of restrictive convenants and solar skyspace
easements can offer increased legal protection for many
1-7
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users of solar energy while minimizing the need for
modification of the present legal system.
Major modifications in the legal system, such as allocation
of sunlight under the prior appropriation system currently
used for water allocation in the Western States, or
under some form of permit procedure, must be carefully
considered to determine whether the resulting increase
in regulation can effectively solve the problems presented
without creating serious negative effects, such as
over-restriction of adjacent property.
ENVIRONMENTAL CONSIDERATIONS
There are minor potential air, water, solid waste, and
health impacts of widespread solar development. Both positive
effects (reduced air and water emissions from conventional
energy sources) and negative effects (disposal of toxic
fluids, increased glare, potential contamination of potable
water systems) exist.
Air pollution affects the availability of solar energy.
1-8
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CHAPTER II
AVAILABLE SOLAR ENERGY IN THE PACIFIC NORTHWEST
Prepared by
Terry M. Dolan
U. S. Department of Energy
Region X
Seattle, Washington
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Introduction
The amount of sunshine available for solar heating at various
locations around the Pacific Northwest has been the subject
of some controversy. There is a wide variety of opinion
regarding the "practicality" of solar heating in (for example)
Seattle which has a national reputation for dark rainy
winters. Some have expressed the idea that solar heating
"is more practical in Spokane or Boise where there is more
winter sun." This chapter is intended to provide objective
data, quantifying the amount of solar radiation* available
for Northwest heating and cooling. We have tried to present
the data in a manner that would be useful for someone
designing a solar heating or cooling system.
This chapter is not intended to be a comprehensive text on
the subject of solar radiation. For further information,
the references listed at the end of this chapter, plus a
college physics text on electromagnetic wave theory, should
prove useful.
Throughout this report the terms "solar radiation" and
"insolation" will be used interchangeably. See
Appendix B for Glossary of Terms and Abbreviations.
II-l
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This chapter follows a sequential development in which we:
1.	Provide a tabulation of available solar energy on
a horizontal surface at many Northwest locations,
2.	Discuss trie make-up of total solar radiation by
its direct and diffuse component parts,
3.	Use the above information to calculate the available
solar energy shining on south-facing collectors at
various Northwest locations, and
4.	Compare available solar energy to the relative
heating loads at various Northwest locations.
Summarizing conclusions are contained at the end of this
chapter.
Solar Energy on a Horizontal Surface
Only a portion of the sun's radiated energy reaches the
surface of the earth. This energy is in the form of electro-
magnetic radiation. The surface temperature of the earth is
relatively constant as a result of an annual balance
II-2
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between the shortwave (0.3 - 3.tyu) radiation received from
the sun and the loss of heat to the atmosphere from the
1
earth in the form of long wave (3.0 - 3 0yu) radiation.
The National Weather Service* measures ground level insolation
2
values at many weather stations around the country. The
amounts of insolation at these stations vary widely, depending
upon such things as local weather conditions, latitude, and
local pollutants. Table II-l is a tabulation of such insola-
tion values for several Northwest locations. These data are
statistical averages of insolation levels recorded over
periods of time ranging from five to 20 years. These measured
insolation values represent the amount of energy falling on
a horizontal surface. Figure II-l shows the geographic
location of the weather stations listed in Table II-l.
Maximum collection is achieved by a surface that is perpendicular
to the sun's rays. Because the sun's rays strike the earth's
surface at varying angles due to the earth's curvature and
the tilt of its axis, the amount of energy received by a
Some data were collected by the predecessor agency, the
U.S. Weather Bureau.
II-3
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INSOLATION LEVELS ON A HORIZONTAL SURFACE AT VARIOUS NORTHWEST LOCATIONS
TABLE Il-l



Insolation*
Levels
(Btu/ft
2-day)






Location
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
Annual
Average
Washington
Friday Harbor
320
580
1000
1500
1900
2100
2200
1900
1300
720
380
280
1200
Prosser
450
840
1300
1900
2300
2600
2600
2200
1700
1000
530
370
1500
Pullman
420
700
1200
1600
1900
2300
2500
1900
1400
940
480
360
1300
Richland
410
760
1300
1700
2100
2300
2400
2100
1500
970
490
350
1400
Seattle (Sea-Tac Airport)
280
550
980
1400
1900
1900
2100
1700
1200
720
370
230
1100
Spokane
410
730
1200
1600
2100
2200
2400
2000
1500
860
450
280
1300
Oregon
Astoria
320
600
1000
1400
1800
1800
1900
1700
1300
770
410
270
1100
Corvallis
370
530
870
1200
1700
1900
2100
1700
1300
780
380
250
1100
Klamath Falls
550
840
1300
1800
2100
2200
2300
2100
1600
1100
580
470
1400
Medford
440
790
1300
1800
2000
2400
2600
2200
1700
1100
540
350
1400
Idaho
Boise
520
880
1300
1800
2200
2300
2500
2100
1700
1100
630
450
1500
Twin Falls
600
890
1300
1700
2000
2200
2200
2000
1600
1100
650
480
1400
* All data represent statistical averages and are rounded to two significant digits. Weather Service data are
reported in units of Langleys (one gram calorie per square centimeter). The above data were converted by use of
the conversion factor: 1 Langley = 3.687 Btu/ft^-day.
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Friday Harbor
WASHINGTON
!• Seattl
Spokane
PulIman
• Prosser
• Richland
OREGON
IDAHO
• Boise
• Twin Falls
• Med ford
• Klamath Falls
FIGURE Ii-i
Location of weather stations reporting
insolation data
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surface can be optimized by tilting that surface an appropriate
amount from horizontal to help compensate for such variations.*
During the northern hemisphere's "winter," the position of
the sun varies from alignment with the earth's equator
(September 21st), to a position 23° 47' south of the equator
(December 21st), and then back to alignment with the equator
(March 21st). In order for a collector to be oriented
perpendicular to the sun's rays at noon (in the northern
hemisphere) it must be south-facing and raised above the
horizontal by an angle equal to its latitude position plus
the angle the sun has "dropped" below the equator. Therefore,
for approximate maximum average winter collection, south-
facing flat plate collectors in the northern hemisphere are
raised above the horizontal at an angle of latitude plus
about 10 degrees (the 10 degrees corresponds to about one-
half of the sun's maximum deviation	23° 47'	from alignment
with the equator). For best average summer collection, the
angle would be latitude minus about 10 degrees.**
* Except for certain locations near the equator where the
optimum position for a collector is horizontal.
** Later in this chapter the sensitivity of solar energy
collection to collector angle will be quantified (see
Table II-2).
II-6
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Direct and Diffuse Components of Insolation
The following section of this chapter represents a
quantification of the available insolation for south-facing
tilted collectors. The average daily radiation incident
on south-facing sloping surfaces is calculated for various
Northwest locations, based on horizontal measurements by the
National Weather Service and its predecessor agency, the
U. S. Weather Bureau. Because this calculation method is
based on actual weather records (statistical averages over
periods of time ranging from five to 20 years), it differs
from the many other works on this topic which rely entirely
on either theoretical methods or short-term data collected
as part of various solar research/demonstration projects.
The total solar radiation (energy) falling on any flat
surface on earth is the sum of: (1) direct solar radiation,
(2) diffuse solar radiation, and (3) reflected solar radia-
tion. On a clear, sunny day, the direct solar component
accounts for the great majority of the total radiation.
Diffuse radiation is the component of radiation that is
scattered by gas molecules, water vapor, and pollutants in
the earth's atmosphere. On cloudy days, insolation
may be composed entirely of diffuse radiation. Reflected
radiation is that component of total insolation reflected by
II-7
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the ground, adjoining roofs, or from specially designed
surfaces intended to increase total solar collection.
The clear day direct component of solar radiation has long
been of interest to building design engineers and architects.
This theoretical cle^r day radiation is similar to the
conditions typical of sunny days, and is a major parameter
affecting conventional building heat gain and, therefore,
the design of air conditioning systems. The American
Society of Heating, Refrigerating, and Air Conditioning
Engineers (ASHRAE) has published tables and formulae describ-
ing theoretical clear day insolation received by south
1
facing surfaces. The ASHRAE data consider primarily the
direct component of insolation and are based on the trigonometric
relationship between the sun and various collector orientations
at various locations on the earth's surface. These tables
and formulae can not be used to predict insolation levels
for cloudy or partly cloudy weather.
The amount of cloud cover determines both the overall magnitude
of total radiation received and the relative distribution of
insolation between its direct and diffuse components. Using
data from the weather stations that measure both diffuse and
3
total radiation, Liu and Jordan developed an empirical
II-8
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relationship for determining the diffuse component of solar
radiation as a function of total radiation. The critical
parameter for the analysis of the direct and diffuse components
is the ratio of the average daily insolation received on a
horizontal surface on earth to the daily radiation received
on a surface outside the earth's atmosphere.
Figure II-2 shows the amount of extraterrestrial daily
radiation for various latitudes while Figure II-3 shows the
ratio of the monthly average daily diffuse radiation to the
monthly average total radiation as a function of cloudiness.
3
Both Figures II-2 and II-3 are taken from Liu and Jordan .
The relationships shown in Figure II-3 are empirical and
based on statistical averages of data collected over several
years.
II-9
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NORTH LATITUDE, L, DEGREES
FIGURE II-2
EXTRATERRESTRIAL DAILY INSOLATION
RECEIVED ON A HORIZONTAL SURFACE
(Taken from Liu and Jordan)3
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RATIO KT«	EXTRATEFRESTR1AL DAILY INSOLATION














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FIGURE II-3
RATIO OF THE MONTHLY AVERAGE DAILY DIFFUSE RADIATION
TO THE MONTHLY AVERAGE TOTAL RADIATION AS A FUNCTION
OF CLOUDINESS, KT
(Taken from Liu and Jordan)3
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Available Solar Energy on South-Facing Collectors
Once the magnitude of the direct and diffuse components of
total radiation are known, the direct component can be
computed for any collector slope and orientation using
published ASHRAE equations.^^ The diffuse component can
also be computed for various collector angles if simplifying
assumptions; are made to facilitate the calculation. To aid
in calculating the diffuse component of insolation, we will
assume that the sky is uniformly bright in all directions.*
We can then calculate the diffuse component by multiplying:
(1) the ratio of diffuse to total radiation (taken from
Figure II-3), by (2) the total radiation on a horizontal surface,
and (3) the fraction of sky exposed to the collector. The
fraction of sky exposed to the collector would depend on
collector tilt: it ranges from a value of unity for horizontal
collectors to a value of one-half for vertical collectors.
The reflected component of solar radiation is a function of
the area surrounding the collector system and is often
beyond the designer's control. Thus, effects of ground
reflection are not included in the ASHRAE tables and formulae.^*
Since diffuse radiation by its very nature is non-directional,
it is believed that this assumption does not introduce
significant error into the results.
11-12
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Similarly, Liu and Jordan^ purposely did not include the
effects of such reflected radiation* and this paper also
follows that practice. Further reasons for not including
effects of the reflected component in this paper are the
extremely wide variation in reflecting surfaces and the
desire to provide design data which are conservative.
Using the above described methods and assumptions, Baker
and Reynolds^ calculated insolation levels for south-facing
collectors at many Pacific Northwest locations. They included
in their calculations a reflected component of insolation
based on an assumed terrestrial reflection. Table II-2
lists the total of the direct and diffuse (but not reflected)
components of insolation computed by Baker and Reynolds^
(rounded to two significant digits) for south-facing collectors.
These insolation values differ from ASHRAE and other theoretical
values for tilted collectors because they are computed from
historical Northwest insolation data. Angles are measured
from the horizontal. Approximate values for other tilt
angles can be computed by arithmetic interpolation. Horizontal
total insolation values are taken from Weather Service
records.
^ Later, Liu and Jordon did undertake a study of the
quantitative effects of reflected insolation as it
relates to flat plate collector performance.
11-13
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INSOLATION LEVELS ON SOUTH-FACING SURFACES AT VARIOUS NORTHWEST LOCATIONS
TABLE II-2
Insolation Levels* (Btu/ft2-day)
Location	Horiz	15°	30°	45°	gp0	750
WASHINGTON
Friday Harbor
JAN
320
440
540
620
660
670
650
0.36
FEB
580
730
840
920
950
930
870
0.42
MAR
1000
1100
1300
1300
1200
1100
1000
0.48
APR
1500
1600
1600
1500
1400
1200
930
0.53
MAY
1900
1900
1700
1600
1300
1100
800
0.54
JUNE
2100
2000
1900
1600
1400
1100
750
0.57
JULY
2200
2100
2000
1700
1500
1100
810
0.60
AUG
1900
1900
1900
1800
1600
1300
980
0.60
SEPT
1300
1400
1500
1500
1400
1300
1100
0.55
OCT
720
870
990
1100
1100
1000
950
0.46
NOV
380
510
620
700
740
750
720
0.38
DEC
280
400
510
590
640
660
640
0.37
Prosser
JAN
450
630
780
890
950
960
910
0.45
FEB
840
1100
1300
1400
1500
1400
1300
0. 56
MAR
1300
1500
1600
1600
1600
1500
1300
0.58
APR
1900
2000
2000
1900
1700
1400
1100
0.65
MAY
2300
2200
2100
1900
1600
12 00
870
0. 64
JUNE
2600
2500
2300
2000
1600
1200
790
0.68
JULY
2600
2600
2400
2100
1800
1300
870
0.72
AUG
2200
2300
2200
2100
1800
1500
1100
0.69
SEPT
1700
2000
2100
2100
2000
1800
1500
0.71
OCT
1000
1300
1500
1600
1600
1600
1400
0.60
NOV
530
730
890
1000
1100
1100
1000
0.48
DEC
370
540
680
790
850
870
840
0 . 43
* All data represent statistical averages and are rounded to two significant digits.
Reflected component of insolation is not included.
** Taken from Figure II-3
-------
Location
Horiz 15°
WASHINGTON (cont'd)
Pullman
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
Richland
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
420	580
700	880
1200	1300
1600	1600
1900	1900
2300	2200
2500	2400
1900	2000
1400	1600
940	1200
480	650
360	520
410	560
760	960
1300	1400
1700	1800
2100	2100
2300	2200
2400	2300
2100	2100
1500	1700
970	1200
490	660
350	500
TABLE I1-2
(cont'd)
30°	45°	60°	75°	Vert Km**
720	820
1000	1100
1400	1500
1600	1500
1800	1600
2000	1800
2300	2000
1900	1800
1700	1700
1400	1400
800	900
660	770
880	880
1100	1100
1400	1300
1300	1100
1300	1100
1500	1100
1700	1300
1600	1300
1600	1400
1500	1400
960	960
830	850
850	0.43
1000	0.48
1100	0.54
900	0.53
770	0.55
750	0.62
860	0.68
960	0.61
1200	0.59
1300	0.57
910	0.44
820	0.42
680	770
1100	1200
1600	1600
1800	1700
2000	1800
2000	1700
2200	1900
2100	1900
1800	1800
1400	1500
800	900
640	730
830	830
1300	1200
1500	1400
1500	1300
1500	1200
1400	1100
1600	1200
1700	1400
1700	1500
1500	1500
950	950
790	800
790	0.41
1100	0.51
1200	0.57
990	0.58
830	0.60
740	0.61
820	0.66
1000	0-66
1200	0.62
1300	0.57
900	0.44
780	0.41
-------
TABLE II-2
(cont1d)
Location	Horiz	15£	30f	45f	60f	75^	Vert	KT**
WASHINGTON (cont'd)
Seattle (Sea-Tac
Airport)
JAN
280
350
410
450
470
450
450
0.30
FEB
550
670
760
820
830
810
760
0.38
MAR
980
1100
1200
1200
1100
1^00
920
0. 46
APR
1400
1500
1400
1400
1200
1000
830
0.49
MAY
1900
1800
1700
1500
1300
1000
760
0.53
JUNE
1900
1800
1700
1500
1200
950
680
0. 52
JULY
2100
2000
1900
1700
1400
1100
770
0. 58
AUG
1700
1700
1700
1500
1400
1100
870
0. 55
SEPT
1200
1300
1400
1400
1300
1200
1000
0. 52
OCT
720
860
960
1000
1000
990
910
0.44
NOV
370
480
580
640
680
680
650
0. 36
DEC
230
300
350
400
420
420
410
0. 29
Spokane
JAN
410
590
740
850
920
930
890
0.44
FEB
730
940
1100
1200
1300
1200
1100
0. 51
MAR
1200
1400
1500
1500
1500
1400
1200
0.5 5
APR
1600
1700
1700
1600
1500
1200
980
0. 56
MAY
2100
2000
1900
1700
1500
1200
840
0.59
JUNE
2200
2100
2000
1700
1400
1100
750
0.59
JULY
2400
2400
2200
2000
1600
1300
870
0.67
AUG
2000
2100
2000
1900
1700
1400
1000
0.65
SEPT
1500
1700
1800
1800
1700
1500
1300
0.62
OCT
860
1100
1200
1300
1300
1300
1200
0.53
NOV
450
620
760
860
920
920
880
0.44
DEC
280
400
500
570
620
630
610
0.36
-------
Location
Horiz	15°
OREGON
Astoria
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
320
600
1000
1400
1800
1800
1900
1700
1300
770
410
270
400
730
1100
1400
1700
1700
1800
1700
1400
920
530
340
Corvallis
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
370
530
870
1200
1700
1900
2100
1700
1300
780
380
250
470
600
940
1200
1700
1800
2000
1700
1500
910
460
300
TABLE II-2
(cont *d)
30°	45°	60°	75°	Vert	Krp**
470
520
540
550
520
0.32
820
880
900
870
810
0.40
1200
1200
1100
1100
920
0.46
1400
1300
1200
1000
800
0.48
1600
1500
1200
980
720
0.51
1600
1400
1100
880
630
0.49
1700
1500
1200
980
700
0.53
1600
1500
1300
1100
830
0.53
1500
1500
1400
1200
1000
0.54
1000
1100
1100
1100
960
0.46
630
700
730
730
700
0.37
400
450
480
480
460
0.30
550
610
630
630
600
0.34
660
690
690
660
610
0.33
970
960
910
830
720
0.39
1200
1100
980
830
660
0.41
1600
1400
1200
920
670
0.49
1700
1400
1200
910
640
0.52
1900
1600
1400
1000
720
0.58
1700
1500
1300
1100
820
0.55
1500
1500
1400
1200
1000
0.54
1000
1100
1100
900
900
0.44
530
570
590
580
550
0.32
340
370
380
380
360
0.27
-------
Location
Horiz 15°
OREGON (cont'd)
Klamath Falls
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
Medford
JAN
FEB
MAR
APR
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
550	720
840	1000
1300	1400
1800	1900
2100	2100
2200	2100
2300	2200
2100	2100
1600	1800
1100	1300
580	750
470	630
440	540
790	950
1300 1400
1800 1800
2000 1900
2400	2300
2600 2500
2200 2200
1700 1900
1100	1300
540	690
350	440
TABLE II-2
(cont *d)
o
O
rn
45°
O
O
<*0
75°
Vert
K *
860
950
1000
990
930
	tp—
0.44
1200
1200
1200
1200
1100
0.49
1500
1500
1400
1300
1100
0.54
1800
1700
1500
1700
830
0.59
1900
1700
1400
1100
730
0 .60
1900
1600
1300
970
640
0.59
2100
1800
1500
1100
700
0.64
2000
1800
1600
1300
900
0.64
1800
1800
1700
1500
1200
0. 62
1500
1600
1600
1500
1300
0 . 58
870
960
1000
980
920
0.44
760
860
910
910
860
0.43
630
680
710
700
660
0. 36
1100
1100
1100
1100
990
0. 46
1500
1500
1400
1300
1100
0 . 53
1800
1700
1500
1200
910
0 . 58
1800
1600
1300
1000
700
0. 56
2100
1800
1400
1000
660
0 . 64
2300
2000
1600
1200
750
0. 70
2200
2000
1700
1400
960
0 . 68
1900
1900
1800
1600
1300
0. 66
1400
1500
1500
1400
1200
0.56
800
870
900
890
830
0 . 41
510
560
580
580
550
0.32
-------
TABLE II-2
(cont'd)
Location	Horiz	15°	30°	45°	60^	75f	Vert	KT**
IDAHO
Boise
JAN
520
700
840
950
1000
1000
940
0.45
FEB
880
1100
1300
1400
1400
1300
1200
0.54
MAR
1300
1400
1500
1600
1500
1400
1200
0.56
APR
1800
1800
1800
1700
1500
1200
950
0 .59
MAY
2200
2100
2000
1800
1500
1100
770
0 . 61
JUNE
2300
2200
2000
1700
1400
1000
680
0. 62
JULY
2500
2400
2200
1900
1600
1200
770
0.68
AUG
2100
2100
2100
1900
1600
1300
960
0.66
SEPT
1700
1900
2000
2000
1800
1600
1300
0.67
OCT
1100
1400
1600
1700
1700
1600
1500
0.62
NOV
630
840
1000
1100
1200
1200
1100
0. 50
DEC
450
630
770
880
940
950
900
0.44
Twin Falls
JAN
600
810
980
1100
1200
1200
1100
0. 50
FEB
890
1100
1200
1300
1300
1300
1200
0. 52
MAR
1300
1500
1500
1600
1500
1300
1100
0.56
APR
1700
1700
1700
1600
1400
1200
880
0.56
MAY
2000
2000
1800
1600
1300
1000
720
0. 57
JUNE
2200
2100
1900
1600
1300
960
640
0.58
JULY
2200
2100
1900
1700
1400
1000
690
0.61
AUG
2000
2000
1900
1800
1500
1200
880
0.62
SEPT
1600
1700
1800
1800
1700
1500
1200
0. 62
OCT
1000
1300
1400
1500
1500
1400
1300
0. 56
NOV
650
850
1000
1100
1200
1200
1100
0. 50
DEC
480
660
810
920
980
980
940
0.45
-------
Northwest Weather
Examination of Table II-l and II-2 data reveals a wide
variation in insolation levels and suggests that some Pacific
Northwest locations would be more suitable for solar energy
utilization than others. In making this statement, however,
consideration must be given to type of application. Solar
water heating feasibility is almost entirely a function of
amount of insolation and is fairly independent of outside
air temperature.* On the other hand, solar space heating
feasibility is dependent on the amount of insolation avail-
able in relation to the weather (i.e., how much cold is
experienced at a particular location). An indication of the
relative feasibility of the application of the solar energy
at various locations can be obtained by comparing the ratios
of the amount of solar energy received to the heating degree
days** for those locations. This arbitrary measure of solar
heating feasibility will be defined for this paper as the
"Solar Heating Index" and have the units of Btu/ft^-degree.
Water heating is slightly affected by outside air
temperature because the efficiency of flat plate solar
collectors decreases with colder outside temperatures.
Heating degree day data are compiled by the U.S. Weather
Service. One heating degree day is defined as a 24-
hour period in which the outdoor temperature averages
one degree below 65°F. A 24-hour period with an average
outdoor temperature of 58°F would account for seven
degree days.
11-20
-------
INSOLATION, HEATING DEGREE DAYS,
and SOLAR HEATING INDEXES
for VARIOUS NORTHWEST and SELECTED
OTHER LOCATIONS
TABLE II-3
LOCATION
AVERAGE DAILY
SOLAR ENERGY
RECEIVED DURING
THE HEATING
SEASON
Btu/ft^-day
(OCTOBER-MARCH
from Table II-l)
AVERAGE MONTHLY
HEATING DEGREE
DAYS DURING THE
HEATING SEASON*
(OCTOBER-MARCH)
SOLAR
HEATING INDEX
Btu/ft2-degree
Washington
Friday Harbor
Prosser
Pullman
Richland
Seattle
Spokane
550
750
680
720
560
660
700**
750
890
690
660
920
0.78
1.00
0.77
1.00
0.79
0.72
Oregon
Astoria
Corvallis
Klamath Falls
Medford
560
530
810
750
610
610
840
700
0.92
0.88
0.96
0.10
Idaho
Boise
Twin Falls
810
840
820
860
0 .99
0.98
Other Locations***
Madison, Wisconsin
Chicago, Illinois
Schenectady, New York
Boston, Massachusetts
Great Falls, Montana
710
530
640
680
770
1100
880
950
800
1000
0.64
0.60
0.67
0.85
0.77
**
***
Heating degree day data (base 65°F, 1931-1960) taken from
Reference 6 (rounded to two significant digits).
Bellingham, Washington degree day data from Reference 6
are used (rounded to two significant digits).
Insolation and heating degree day data are taken from
Reference 7 (rounded to two significant digits).
11-21
-------
Table II-3 represents a tabulation of Solar Heating Indexes
for various Northwest locations; and, for comparison, Solar
Heating Indexes for some other locations outside the Region
are also given.*
Conclusions
1.	Solar collection in Northwest latitudes is improved
significantly during winter months by tilting collector
surfaces 45° to 60° above horizontal, facing south.
Available solar energy on such inclined south-facing
surfaces is approximately twice that of horizontal
surfaces during November, December, and January. See
Table II-2 for detailed data.
2.	Based only on climatic factors, the attractiveness of
solar space heating, as measured by the Solar Heating
The "Index" is not an accurate indicator for comparing
available solar energy for locations at widely different
latitudes because collector orientation (tilt) normally
increases with latitude. However, because the Index
is, indeed, simply an indicator and not intended for
use as a refined analytical extrapolation tool, the
author believes that the results achieved using horizontal
data for sites that are of approximately the same
latitude are sufficiently accurate for the intended use
of the Index and do not compromise the conclusions of
this chapter.
11-22
-------
Index, is relatively uniform throughout the Northwest.
This uniformity is due to two related conditions. West
of the Cascade Mountains, it is cloudier, but more
temperate; east of the Cascades, there is more available
solar radiation, but the winters are colder. These
conditions roughly balance each other. The Richland/
Prosser area of Washington, and the Medford, Oregon
area are appear to be the most attractive areas for
solar space heating applications {based solely on
weather conditions). A realistic analysis of solar
heating attractiveness must include economic analysis;
such analysis is developed in Chapter III of this
report. See Table II-3 for a tablulation of Solar
Heating Indexes.
3.	Based on climatic factors, the attractiveness of solar
space heating, as measured by the Solar Heating Index,
is "better" for most Northwest locations studied than
for other typical Northern locations surveyed (Chicago,
Illinois; Madison, Wisconsin; Schenectady, New York;
and Great Falls, Montana). See Table II-3 for a tabulation
of Solar Heating Indexes.
4.	Based on a consideration of available solar radiation,
solar water heating, which is not usually affected by
11-23
-------
outside air temperatures, appears to be more attractive
in the clear-sky eastern portions of the region. See
Table II-2 for a tabulation of insolation levels.
11-24
-------
REFERENCES FOR CHAPTER 2
1.	"Solar Energy Utilization for Heating and Cooling,"
ASHRAE Handbook and Product Directory 1974 Applications
Volume, Chapter 59.
2.	"Climatic Atlas of the United States," U.S. Department
of Commerce INOAA), National Climatic Center
3.	"The Interrelationship and Characteristic Distribution
of Direct, Diffuse and Total Solar Radiation," Benjamin
Y. H. Liu and Richard C. Jordan, Solar Energy, Vol 4,
No 3, 1960.
4.	"Development and Use of Solar Insolation Data in Northern
Latitudes for South Facing Surfaces," Clayton A. Morrison
and Erich A. Farber, ASHRAE Paper No 74-1, 1974.
5.	"Insolation on South Facing Tilted Surfaces: Pacific
Northwest Locations," M. Stephen Becker and John S.
Reynolds, University of Oregon 1975.
6.	"Climatological Handbook, Columbia Basin States,
Temperature, Volume 1, Part B," Pacific Northwest River
Basins Commission, pp. 438-441.
11-25
-------
7. "Buying Solar," Federal Energy Administration, 1976,
U.S. Printing Office Stock No. 041-018-00120-4.
11-26
-------
CHAPTER III
TECHNOLOGY AND ECONOMIC ANALYSIS
Prepared by
G. L. Liffick
U.S. Department of Energy
Richland, Washington
H. L. Parry
Pacific Northwest Laboratory
Richland, Washington
-------
Introduction
The purpose of this chapter is to review the current
economic feasibility of residential solar space and hot
water heating in the Pacific Northwest (PNW). Where pos-
sible, quantitative examples have been included. It is
recognized that economics are not the sole basis for home-
owner investment decisions and solar systems may be
installed for non-economic reasons, including prestige,
novelty and a personal desire to reduce the use of non-
renewable resources. No attempt has been made to quantify
the value of these non-economic incentives.
Solar Systems
Active Heating Systems
The most studied and discussed type of solar heating
system is commonly referred to as the active heating system,
in which solar energy is collected and distributed by
mechanical means. Figure III-l shows the major components
of a typical active solar heating system. These components
include the solar collector, thermal storage, the heat
distribution system, the control system and the auxiliary
system.
The simple flat plate collector is the most common
device used for collecting solar radiation. It consists
of the following:
III-l
-------
SOLAR
COLLECTORS
THERMAL
STORAGE
CONTROL
SYSTEM
AUXILIARY
SYSTEM
DISTRIBUTION
SYSTEM
FIGURE III-l. Major Components of an Active Solar Heating System
-------
1.	an absorber plate, usually made of metal with a black
coating to increase absorption of the sun's heat;
2.	working fluid passages, usually bonded to or formed
into the absorber, through which either air or a liquid
pass to remove heat from the absorber (The heated fluid
is then transported to areas of use or to storage); and
3.	an enclosure, insulated on the back, with one or more
transparent cover sheets to trap heat within the col-
lector and reduce heat losses from the absorber.
Storage of solar energy is often necessary because heat
is needed at night or on cloudy days when collection is not
occurring. The most common means of storing energy is by
storing solar heated water in a large tank (usually used
when liquid is the heat transfer fluid) or by using solar
heated air to heat a bin of rocks. This stored heat can then
be withdrawn from storage when needed.
The heat distribution system receives energy from the
collectors or storage and distributes it to where it is
needed in the building. Typically, heat is distributed
throughout the building in the form of warm air or warm
water.
The control system performs functions similar to those
of a thermostat in a conventional heating system. It senses
the need for heat in the building, decides whether that heat
III-3
-------
1.	an absorber plate, usually made of metal with a black
coating to increase absorption of the sun's heat;
2.	working fluid passages, usually bonded to or formed
into the absorber, through which either air or a liquid
pass to remove heat from the absorber (The heated fluid
is then transported to areas of use or to storage); and
3.	an enclosure, insulated on the back, with one or more
transparent cover sheets to trap heat within the col-
lector and reduce heat losses from the absorber.
Storage of solar energy is often necessary because heat
is needed at night or on cloudy days when collection is not
occurring. The most common means of storing energy is by
storing solar heated water in a large tank (usually used
when liquid is the heat transfer fluid) or by using solar
heated air to heat a bin of rocks. This stored heat can then
be withdrawn from storage when needed.
The heat distribution system receives energy from the
collectors or storage and distributes it to where it is
needed in the building. Typically, heat is distributed
throughout the building in the form of warm air or warm
water.
The control system performs functions similar to those
of a thermostat in a conventional heating system. It senses
the need for heat in the building, decides whether that heat
III-3
-------
should be supplied directly from the collectors, from
storage, or by the auxiliary unit, and then operates the
necessary pumps, valves, and fans to provide the needed
heat.
During periods of extreme cold or after extended
cloudy weather, an auxiliary heating system is needed as
back-up energy supply. The auxiliary system uses a conven-
tional energy source, such as oil, gas, or electricity, to
provide necessary heat until solar energy is again avail-
able. Often the auxiliary system uses the same heat distri-
bution component as the solar heating system.
Actual solar heating systems are more complex than the
simple conceptual sketch shown in Figure III-l. Figures III-2
and III-3 show more detailed layouts of typical air and
liquid systems which provide both building heat and domestic
hot water. Figure III-4 shows a detailed layout of a system
which provides only domestic hot water. Discussion of the
detailed design of such systems is beyond the scope of this
report but is covered in depth in numerous books and
... . . (1-3)
publications.
Active solar heating systems can be classified into two
groups depending on whether the heat transfer fluid passed
through the collector is air or a liquid (typically water or
a water/antifreeze solution). Neither system has any clear
III-4
-------
SOLAR RADIATION
COLLECTION
HOT
WATER
AIR-WATER
HEAT EXCHANGER
DOMESTIC
WATER TANK
f^MH_C0LD
HEATER WATER

?NACE
¦msA*
°a.giC,

r\V °62,o
*i- o-nOc
ZXdSLa
ROCKS
COLD SIDE
HOT SIDE
FIGURE III-2. A Typical Air System
III-5
-------
SOLAR RADIATION
COLLECTOR
COLLECTOR
LIQUID
BACKUP
FURNACE
AIR
DOMESTIC
WATER TANK
~ HOT
WATER
WATER STORAGE
TANK
HEATER
COLD WATER
FIGURE III-3,
A Typical
II1-6
Liquid
System
-------
SOLAR
RADIATION	EXPANSION
TANK
STORAGE
TANK
SOLAR
COLLECTORS
» HOT WATER
AUXILIARY
WATER HEATER
PUMP
COLD
WATER
FIGURE III-4. A Solar Domestic Water Heating System
-------
superiority over the other, each having its own advantages
and disadvantages. Moreover, system performance and costs
appear to be comparable with either an air or liquid system.
The relative merits and problems associated with each system
are shown below.
Advantages of liquid systems over air systems include
the following:
1.	Piping is smaller and easier to route than the ducting
used for air systems. This greatly simplifies installa-
tion of a system in an existing building.
2.	Water is a more efficient heat transfer medium than
air so that heat exchangers used for domestic hot water
systems can be smaller.
3.	The high specific heat of water means that the water
tank heat storage units typically used with liquid sys-
tems will take up less space than an equivalent rock
bin storage unit typically used with an air system.
4.	Less auxiliary energy is required for circulating liquid
in a well-designed liquid system than for circulating
air in a typical air system.
5.	In some areas, an air system's rock bed storage unit
must be protected from dust. This requires installa-
tion and periodic servicing of duct air filters.
III-8
-------
6.	In humid areas, an air system's rock bed storage unit
may provide an environment for the growth of fungus
and mildew, which might give circulated air an undesir-
able smell.
7.	Liquid systems are, at the present time, more common
than air systems, and therefore a wider choice of com-
ponents and installers is available.
Advantages of air systems over liquid systems include
the following:
1.	Corrosion and freezing, which can be disastrous in a
liquid system, are not a problem with an air system.
2.	Leakage in an air system does not have the serious con-
sequences it may have in a liquid system.
3.	In an air system, there is no danger of a leak contam-
inating the domestic hot water system with antifreeze as
may be true of a liquid system.
4.	In areas with hot summer days but cool nights (as in
much of the PNW) the rock bed storage unit can be
cooled with outside air during the night and used to
help keep the building cool during the day. In this
way, part of the solar heating system can be used as
a summer cooling system.
III-9
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No general statement can be made regarding the super-
iority of air or liquid systems in the PNW. For space heat-
ing, either system can be effective if properly designed.
The air system's summer cooling potential and lack of
freezing problems make it a particularly attractive applica-
tion in inland areas. However, the availability of compo-
nents and relative ease of installing piping compared to
ducting may sway the decision toward a liquid system, partic-
ularly for an existing building. For a system designed
solely to heat domestic water, a liquid system appears to be
preferable, if only because of the large number of suppliers
now offering complete solar domestic hot water systems using
liquid collectors.
Active solar heating and/or hot water systems are
currently cost effective in some areas of the PNW. The
third major section of this chapter, "Active Systems Analysis,"
presents information on system cost effectiveness for those
PNW locations where solar data are available.
Passive Heating Systems
Passive solar heating systems, in which thermal energy
flow is by natural means, are not as common or as well under-
stood as active systems. However, recent research^®^
indicates that passive concepts may be quite effective in
the PNW. Most passive heating systems suitable for the
PNW can be divided into three basic categories: direct gain,
111-10
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thermal storage wall, and attached greenhouses. Sketches
of these concepts are shown in Figure III-5.
The direct gain system is the most simple approach to
passive solar heating. It utilizes an expanse of south-
facing double window combined with a large amount of thermal
mass, usually a masonry floor and masonry walls with insul-
ation on the outside. The building itself becomes a
live-in solar collector. Solar radiation passes through
the glass and heats the massive walls and floor, which act
as combined absorbers and heat storage units. Movable
insulating panels may be used to cover the windows when
energy is not being collected, thus minimizing heat loss at
night and during very cloudy days.
The thermal storage wall concept also uses an expanse
of south-facing double window. However, a thermal storage
wall is placed between the window and the living space.
The wall is made of any heat storage material, the most common
being dense concrete, brick, or water in containers. The
wall acts as both absorber and storage unit and is usually
painted a dark color to improve solar absorption. The wall
absorbs solar radiation during the day and then transfers
heat into the living space by radiation and convection. A
modified heat storage wall concept, known as the Trombe Wall,
utilizes vents at the top and bottom of the heat storage wall
Ill-ll
-------
SOLAR RADIATION
STORAGE
MASS
MOVABLE
INSULATION
DOUBLE
GLAZING
DIRECT GAIN
•r\
SOLAR
RADIATION
DOUBLE .
GLAZING

1

V-

'//






STORAGE
MASS
OPTIONAL
[ VENTS
THERMAL STORAGE WALL
SOLAR
RADIATION

STORAGE
MASS
DOUBLE
GLAZING
SOLAR GREENHOUSE
FIGURE III-5. Passive Solar Heating Concepts
111-12
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to allow free convection of room air over the warm outer
wall and then back into the room. This provides an addi-
tional path for heat to enter the living space.
The third passive heating concept is actually a combina-
tion of the first two. It utilizes a greenhouse attached to
the main building with a thermal storage wall between the
two. Solar radiation not only provides heat to the green-
house but also provides enough excess heat in the heat storage
wall to supply some of the requirements of the main building.
The attached greenhouse concept has the advantage of provid-
ing not only building heat but also a place to grow food
during the colder months.
Considerable research on passive systems suitable for
the PNW has been performed at the University of Oregon.
Computer simulations have been carried out to help develop
guidelines for the design of passive systems and to predict
the performance of such systems.^^ Initial results are
impressive and indicate that a properly designed passive
system can perform as well as an active system. As an
example,a well-insulated house (with a heat loss of
8.4 Btu per degree day per ft of floor area) has been simu-
lated for different cities in the PNW. The house has a
thermal storage wall heating system utilizing a 12-inch-
thick concrete thermal storage wall equal in area to 1/2
the house floor area. The results are shown in Table III-l.
111-13
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TABLE III-l. Computer Simulations of Performance
of Passive Systems
City
Percent Heating
Supplied by Solar
Eugene, OR
59
Medford, OR
71
Seattle, WA
60
Spokane, WA
61
Boise, ID
71
Additional performance estimates and design guidelines for
the different passive concepts are currently being compiled
by University of Oregon researchers and will be published
as a booklet in early 1978. The booklet will be available
at a modest cost from the Center for Environmental Research,
School of Architecture and Allied Arts, University of
Oregon, Eugene, Oregon 97403.
Passive systems have both advantages and disadvantages
when compared to active systems. Passive systems can be
integrated into new buildings as part of the architecture
at very little additional cost. Thus, they can be very cost
effective. Moreover, because passive systems are so simple
and use standard building materials, maintenance costs should
be almost non-existent. Also, it is possible to combine dif-
ferent passive concepts in a single structure, thus allowing
great flexibility in the arrangement of passive homes and
buildings. On the other hand, it may prove more difficult to
111-14
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retrofit passive systems to existing buildings than to
retrofit active systems. Furthermore, it is easier to con-
trol active systems than passive systems. Temperature in
a passively heated structure will vary during the day, and
although this is not necessarily harmful, most people are
used to maintaining a constant temperature in their homes.
Finally, because passive systems are not as well developed
as active systems, designs and equipment for passive systems
(such as movable insulation systems) are not as available
or well tested as those for active equipment.
Swimming Pool Heaters
Solar swimming pool heaters are the most widely used
of all solar heating systems in the country. Figure III-6
shows a typical schematic for a pool heating system. After
pool water is pumped through a standard pool filter, it
passes through the collector array and then back to the
pool. Manual or automatic valves allow the collectors to
be bypassed on very cloudy days or at night if it is desired
to keep the filter running. The circulation pump is generally
the standard pool pump supplied as part of the filter system.
The pool itself acts as the storage and distribution system.
Swimming pool heaters represent an ideal application
of solar energy for several reasons:
111-15
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SOLAR
RADIATION
V
SOLAR
COLLECTORS
DRAIN VALVE
: SWIMMING
^ POOL
i k
DRAIN VALVE

FILTER
PUMP
AUXILIARY HEATER
(OPTIONAL)
FIGURE III-6. A Solar Swimming Pool Heating System
-------
1.	Swimming pools are generally used from late spring
to fall when the largest amount of solar radiation is
available.
2.	Pools already have a pump as part of their filtration
system and the pool itself acts as the storage and dis-
tribution system. Consequently, the only additional
expense for a solar pool heater is the collector array,
piping and control system. Indeed, the control system
is often no more than a few manual valves to allow
diversion of filtered pool water through the collector.
3.	Because of the low temperatures and pressures involved,
solar pool heaters can use very simple, low-cost unglazed
collectors, often made of plastic.
4.	The relatively low collector operating temperature
results in high collector operating efficiency.
5.	Because of the low pressures and temperatures involved,
it is easy for pool owners to construct their own pool
heating systems, which are quite serviceable.
6.	Swimming pools do not normally have stringent tempera-
ture control requirements. Often the solar pool heater
will be installed with no backup system at all. The
owner allows the pool to reach whatever temperature it
can and if that is still too cold, he simply doesn't
swim.
111-17
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7. Because variations in pool temperature are not a
serious problem and because collectors are inexpen-
sive, sizing of a collector system for a pool is
not as critical as for a house. For this reason,
detailed procedures for sizing pool heaters have not
been developed. Instead, the general rule-of-thumb
has been to use a south-facing collector area of
50 to 75% of the pool surface area. If the pool stays
too cool, collector area can be added. If the pool
gets too hot, the collectors can be bypassed. Moreover,
in many cases the collector area is determined by the
available area of mounting surface or by the amount
of material the pool owner has available for his
collectors.
A detailed economic analysis of solar pool heaters
is difficult because so much depends upon the practices
and values of the pool owner. How warm does he want his
pool? Does he object to temperature variation during the
swimming season? How long a swimming season does he
desire? Is he willing to cover his pool at nights to
minimize heat loss? However, it is possible to perform
a very simple analysis which will give an indication of
what the expected payback periods might be for different
cities in the PNW.
Ill-18
-------
2
Table III-2 shows the amount of energy that 1 ft of
typical 30° slope, south facing, swimming pool collector,
operating at 60% efficiency (typical for a pool collector),
might gather during a season from April 1 through September
(12)
30.	The table also shows the equivalent value of that
energy if it .'ere provided by electricity at rates of 1.0,
2.0 and 3.0 cents/kWh (1 kWh = 3413 Btu). It is then
2
simple enough to compare the energy value of 1 ft of
2
collector to the cost of buying and installing that 1 ft
of collector to determine the approximate number of years
it will take to pay for the system. As an example, if
2
electricity costs 2.0 cents/kWh, the value of 1 ft of
pool collector in Corvallis, Oregon, is about $1.06/season
(from Table III-2) . if the pool collector system costs
$4.00/ft to build and install, the system should pay for
itself within 4 years ($4.00/$1.06 saved each year =
3.77 years). Note that this very simple analysis does not
take into account escalating energy costs, the value of
alternative investments, possible tax credits, maintenance
costs, or energy wasted if the solar system is turned off
because the pool is warmer than a particular owner desires.
Consequently, it should be used only as a very rough guide.
However, the table does show that pool heaters can collect
111-19
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TABLE III-2. The Estimated Average Seasonal Value
of 1 ft^ of Swimming Pool Solar
Collector in Various PNW Cities
Value for Different
Net Energy 	 Electric Rates
City
Collected
lC/kWh(aj
2C/kWhla)
3$/kWhia;
Corvallis, OR
53
kWh
$ 0.
53
$ 1.
06
$ 1.59
Medford, OR
67
kWh
0.
67
1.
34
2.01
Seattle, WA
55
kWh
0.
55
1.
10
1.65
Spokane, WA
65
kWh
0.
65
1.
30
1.95
Boise, ID
68
kWh
0.
68
1.
36
2.04
Season from April 1 to September 30.
Collectors facing south at a 30° slope.
Assumed 60% collector efficiency.
(a) For equivalent Natural Gas rates, see Table III-4.
a considerable amount of energy during the swimming season
throughout the PNW and can recover their initial cost in a
fairly short period.
Solar/Heat Pump Combinations
A solar heating system can be combined with a heat
pump to give the system shown in Figure III-7. In this
system the building heat load can be met in one of four
ways:
1. If the solar storage temperature is high enough, the
load can be supplied directly from storage as in a
standard solar heating system.
111-20
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SOLAR RADIATION
SERVICE
HOT
J WATER f
UmMSWMiJ
A/VW1
AMBIENT
AIR
IN
r
HEAT PUMP
STORAGE
TANK
COLLECTOR
CONDITIONED
AIR
HOUSE
RETURN
AIR
FIGURE III-7. A Combined Solar/Heat Pump Heating System
-------
2.	If the storage temperature is too low for direct use,
but is higher than the outside air temperature and
the minimum heat pump supply temperature, the heat
pump will use the stored energy as its heat source.
3.	If storage temperature is lower than outside air tem-
perature, the heat pump will use outside air as its
heat source just as a standard heat pump does.
4.	If both the storage temperature and outside air tem-
perature are too low, the building heat load will be
met entirely by the auxiliary heater (usually an
electric resistance air heater).
An analysis of a solar-assisted heat pump system in the
PNW has been performed by the Environmental Research Center
of Washington State University for the Northwest Energy Policy
Project.	The main finding of the study is that, although
the solar-assisted heat pump system investigated will
require less backup energy than a more standard solar heat-
ing system, the standard solar system is more cost effective.
This is the case even if electric rates over 9 cents/kWh
are used in the analysis. It is possible, however, that
other solar/heat pump combinations, particularly a combina-
tion using very low cost, low temperature collectors to
maintain a moderate heat pump supply temperature, might be
more cost effective than the fairly complex system described
above. To date, the cost effectiveness of this type of
111-22
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system has not been evaluated for PNW locations. However,
research is underway to improve our understanding of solar-
assisted heat pump systems in the PNW (See Appendix A).
Active Systems Analysis
This section presents an economic analysis of four
different solar heating and/or hot water applications for
specific PNW locations. PNW locations with five or more
years of solar radiation data were included. The four
applications considered at each location were:
1.	solar hot water system installed in new construction,^
2.	solar hot water system installed in an existing
structure,^
3.	solar heating and hot water system in new construction,
and
4.	solar heating and hot water system installed in an
existing structure.
FCHART, a computerized design tool developed by the
University of Wisconsin, was used to perform this solar
system economic analysis. The methodology for the analysis
(8)
is similar to that used in Solar Water and Space Heating,
a report prepared by the Mitre Corporation for the Division
of Solar Energy, U.S. Department of Energy (DOE), November
19 76. Certain variables used in the MITRE analysis have
(a) Different loan conditions were used for new construction
and modifications to existing structures (See Table III-3).
111-23
-------
been changed to better reflect PNW conditions. Table ril-J
lists the input variables used for this analysis. The
results of these analyses are curves relating solar system
cost and the cost of electricity to the Years-to-Break-Even
for a cost optimized solar system. Years-to-Break-Even
is the time it takes to recover 100% of the initial cost
of the solar system through savings in electricity costs
considering both inflation and interest charges. The cost
of the solar heating and hot water systems are compared
to electric resistance heating (baseboard units or electric
furnace) costs and electric water heaters. It should be
noted that each solar system was sized to minimize the
Years-to-Break-Even, that is, to be as cost effective as
possible.
The variable values given in Table III-3 are reasonable
values for a typical PNW solar installation. However, they
may differ for a particular system. To determine how
changes in the variables affect the Years-to-Break-Even, a
sensitivity analysis was performed for a representative
2
$20/ft domestic water heating system in Boise, Idaho. The
following parameters were individually varied over the ranges
shown:
Down payment - 0% to 30%
Mortgage interest rate - 7-1/2% to 10-1/2%
Mortgage term - 20 to 30 years
III-24
-------
TABLE III-3. FCHART
Var¦ iable
Descrlj.) tion
Variables Common to All Analyses
Type of Solar System
Collector Orientation
Solar System Costa
Storage
Loan Conditions
Alternative Investment opportunity
Electrical Energy Costs
Operating Costa
Income Tax Rate
Property Tax
Salvage Value
Heating and Hot Water System Variables
Collector Slope
Type of Collector
Thermal toad
Hot Water System Variables
Collector Slope
Type of Collector
Hot Water Load
The liquid system shown in Figure I1I-B.
South facing
System costs of $5, $10, $20 and $30/ft^
were used. These are the incremental
costs of the entire solar sytem (col-
lectors, controls, piping, storage, etc.)
divided by the collector area (ft*). The
incremental cost of the solar system is
the cost above the conventional heating
and/or hot water systems.
1.8 gal/ft^ of collector area.
For new construction a 25-year loan at
8-1/2% annual interest was used. For
solar systems added to existing struc-
tures the loan was 10 yearB at 10% annual
interest.
It was assumed that if an individual does
not buy a solar system this money could
be invested at 8-1/2% (before taxes).
Current electricity costs of 1.0, 2.0,
3.0, 4.0, and 5.0 cents/kWh were used.
These costs were based on FEA projections
published April 15, 1977, in the Federal
Register. See page 111-28 for details.
An annual cost of 1% of the system cost
was used to provide for maintenance and
increased insurance. Inflation of 6%/year
was applied to these costs.
A combined Federal State income tax rate
of 30% was used.
It was assumed that solar systems would be
exempt from property tax. This has
occurred in Oregon and Washington.
It was assumed that at the end of 15 years
the solar system has no salvage value.
See page 111-28 for details.
56° from horizontal
Double-glazed copper tube collector with
FVtu).
0.70 and F'rUl - 0.83.(»>
Building heat loss of 52? Btu/hr/°F.
with an outside design temperature of 18°F
this would re«ult in a 26,350 Btu/hr heat-
ing load (€8® F Inside). Hot water load aa
below.
46° from horizontal.
Single-glaied copper tube collector with
FVTa)n " °-75 and F'rUL " 1-00-(a)
80 gal/day heated from 60° F to 140°F.
(a) F*r(to)n and F'rUl are parameters used to describe the efficiency of solar flat
plate collectors.
111-25
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SERVICE
HOT
WATER
TANK
RELIEF
VALVE
AUXILIARY
HEAT
SOLAR
PRE-
HEAT
TANK
MAIN
STORAGE
TANK
HOUSE
WATER
SUPPLY
AUXILIARY
HEAT
FIGURE III-8. Schematic Diagram of a Liquid-Based Solar
Space and Water Heating System
-------
Property tax rate - 0.5% to 1.5%
Combined federal/state income tax rate - 20% to 40%
Yearly maintenance - 0.5% to 2.0% of system costs
Collector azimuth angle - southeast to southwest
Salvage value - 0% to 100%
With the exception of salvage value, changes in the above
parameters had very little effect on the Years-to-Break-
Even for a cost optimized system. Indeed, the effect was
less than one year. For salvage value the Years-to-
Break-Even increased by three years as the salvage value
increased from 0% to 100% of the original investment.
The reason for this increase is that it becomes more
cost effective to increase the system collector area for
a greater salvage value. This increased area results in
a more cost effective system even though the Years-to-
Break-Even is slightly greater. From the sensitivity
analysis it can be concluded that changes in the above
parameters, with the exception of salvage value, have
very little effect on the Years-to-Break-Even for a cost
optimized solar system in a typical PNW location.
The University of Wisconsin has shown that a FCHART
analysis of a liquid system reasonably approximates the
(9)
performance of a similar air system.	Therefore,
although the Years-to-Break-Even curves developed for
111-27
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each PNW location were based on a liquid system, they may
also be used to approximate a system using air as the
heat transfer fluid.
Future electricity costs are based on DOE (formerly
the Federal Energy Administration) projections published
in the April 15, 1977 Federal Register. Since these
projections do not include inflation, they have been
increased by 6%/year. The combined rate of increase in
electricity costs averages 8%/year over the next 15 years,
with the years 19 77 through 19 81 having approximately an
11%/year increase. Of course, the rate increases of indi-
vidual utilities will vary depending on their future cost
of electricity. For this analysis the DOE combined rate
of increase in electrical costs was then applied to each of
the five present electrical cost figures (1.0, 2.0, 3.0,
4.0 and 5.0 cents/kWh).
Electricity costs in the PNW are currently between
0.8 and 2.5 cents/kWh. The 3- to 5-cents/kWh electricity
costs are included in Figures 111-10 to 111-20 to show
how the Years-to-Break-Even change at higher electricity
costs.
Table III-4 can be used to convert fuel oil and
natural gas prices to the equivalent electricity costs.
Note that the average efficiencies of furnaces and hot
water heaters are included in the conversion table.
III-28
-------
Table III-4.	Equivalent Energy Costs
Electricity,	Oil,Natural Gas,
$/kWh	 $/gal	$/therm^)
0.01 0.28	0.23
0.015 0.43	0.35
0.02 0.57	0.47
0. u 25 0.71	0.59
0.03 0.85	0.70
0.035 1.00	0.82
0.04 1.14	0.94
0.045 1.28	1.05
0.05 1.42	1.17
(a)	Assumes oil with a heating value of
138,700 Btu/gal and 70% furnace efficiency.
(b)	Assumes 80% furnace efficiency.
(c)	1 therm = 100,000 Btu.
The Years-to-Break-Even curves are based on the assump-
tion that the salvage value of the solar system is zero at
the end of 15 years. This means that the purchaser of a
15-year-old solar heated house would not pay more for the
house than a conventionally heated house. Data are not
available to validate or contest this assumption. Consis-
tant with this assumption, only those solar system/electrical
cost combinations that recover 100% of their initial cost
in less than 15 years are included on the Years-to-Break-
Even curves. The salvage value assumption does not mean that
the solar system has a useful life of only 15 years.
111-29
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Pacific Northwest Solar Analysis
For each of the 12 PNW locations where insolation
(incoming solar radiation) data are available, Years-to-
Break-Even curves have been developed. These curves show
the Years-to-Break-Even of cost optimized PNW solar sys-
tems based on the assumptions in Table III-3. Also shown
for each location are the ranges of collection areas and
energy supplied in the cost optimized system. It should
be stressed that although the values shown are felt to be
typical, they should be used only as guides, not fixed
design values. Each potential solar system should be
individually analyzed after the preliminary design has
been completed. Individual analyses based on similar
methods can be obtained for a charge of $10 to $20 from
SOLCOST, U.S. DOE-sponsored computer design service. For
more information write:
Solar Environmental Engineering Co., Inc.
SOLCOST Service Center
P.O. Box 1914
Ft. Collins, Colorado 80522
Phone: 303-221-4370
Accurate prediction of the performance of a solar
heating system is made very difficult by the fact that
performance is dependent upon the local weather—not just
the weather in the local region, but the weather at a
given building site. The weather parameters most affect-
ing a solar system's performance are the following:
111-30
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1.	solar radiation, which determines the energy available
for collection,
2.	ambient temperature, which helps to determine the
amount of energy needed for heating and the effi-
ciency of the collection system, and
3.	wind speed and direction, which also help determine
the energy needed and the collection efficiency.
Although records of average temperature and wind
velocity are available for numerous locations throughout
the PNW, solar radiation data are available for only a
few areas. Furthermore, even if solar radiation data
were available for more areas, system performance predic-
tions would be made difficult by the significant effects
of local terrain and conditions on the microclimate of a
given building site. This is particularly true in coastal
and mountain areas, where sites several miles apart may
have significantly different weather characteristics.
The difficulty in making accurate performance pre-
dictions for a solar heating system at a specific site is
not as serious as it might seem. Most cost effective
solar systems for the PNW will not provide 100% heating
and will need to have an auxiliary heating unit capable
of maintaining an adequate living environment. Consequently,
there should not be undue hardship if a system does not
provide all of the heat predicted. However, the inaccuracy
111-31
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in predicting performance does lead to an inaccuracy in
determining the most economic size of system for a site.
Thus, estimates of the economic viability of solar heating
system, such as those given in this report, should be used
as guidelines only. One must consider how different his
own microclimate is from that of the nearest location for
which performance data are available to decide how applic-
able the performance guidelines will be to his own situation.
Using the Years-to-Break-Even Curve
1.	From your utility bill or by calling the local
utility, determine your average cost of electricity
in cents/kWh. (See Table III-4 for oil or natural
gas heating.)
2
2.	Calculate the total incremental system cost per ft
of collector for the proposed solar system. The total
incremental system cost of the solar system is the
cost above the conventional heating and/or hot water
system cost, and includes the cost of all components,
installation, labor, sales tax, etc. If you are
eligible for a federal or state tax credit or rebate,
subtract this amount from the total incremental system
2
cost. Divide this "net" cost by the ft of collector
area. Typical values for commercially installed
2
solar systems are $20 to $30/ft of collector. Do-it-
2
yourself systems are typically $10 to $20/ft of
collector.
Ill-32
-------
3.	As shown in Figure III-9, find your cost of electricity
(2 cents/kWh), draw a vertical line up to the total
2	2
system cost/ft of collector curve ($20/ft ), and from
v
that point draw a horizontal line over to the vertical
axis to determine the Years-to-Break-Even. In this
example for Boise, Idaho, it will take approximately
12 1/2 years before electricity savings equal the addi-
tional cost of a solar hot-water system. Note that
for heating systems, solar systems are compared to
electric resistance heating (baseboard units or electric
furnace).
2
4.	Collector cost curves not shown, such as $15/ft ,
v->
may be estimated (interpolated) between the existing
curves. However, the curves cannot be extended
(extrapolated) to lower electricity costs. The opti-
mal solar systems in the blank areas either require
more than 15 years to break even or will supply less
than 40% of the total energy requirements.
Economic Analysis by Location
Economic analysis for eleven different locations in
the PNW are presented in Tables III-5 to III-15 and
Figures 111-10 to 111-20. Use of the Years-to-Break-Even
curves is explained on page 111-32. In Tables III-5 to
111-15 the "Percent Energy Supplied" and "Collector Areas"
are for the computer optimized solar systems. "Retrofit"
refers to construction added to an existing structure.
Ill-33
-------
NEW CONSTRUCTION
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE III-9. Hot Water System, Boise, Idaho
III-34
-------
ECONOMIC ANALYSES BY LOCATION
-------
TABLE III-5. Economic Analysis for Boise, ID^a^
A. Percent Energy Supplied by Solar System
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/it2 Cost cents/kwh Construction Retrofit Construction Retrofit
5
1
73
65
53
41

2
81
77
70
62

3
92
83
78
72
10
1
50
(b)
(b)
(b)

2
73
65
53
41

3
79
75
65
55
20
2
50
(b)
(b)
(b)

3
68
54
41
(b)

B. Range
of Optimized Solar
Collector
Areas(f t^)

Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
75
60
305
195

2
100
85
560
425

3
155
10 5
780
605
10
1
40
—
—
—

2
75
60
305
195

3
90
80
460
330
20
2
40
—
--
—

3
65
45
200
—
(a)	FCHART data is based on information from the National Climatic Center,
Asheville, NC. Boise data should be generally applicable to the Snake
River Valley from Mountain Home, ID north to Huntington, OR.
(b)	Less than 40%.
111-36
-------
NEW CONSTRUCTION
BOISE, ID
HOT WATER SYSTEM
14
12
10
8
6
4
2
0
*
S
CE
CQ
ce
s
>-
ADDED TO
EXISTING STRUCTURE
12 3 4 5
COST OF ELECTRICITY cents/kWh
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
-
NEW CONSTRUCTION
¦
. $30/ft2r
V
\ \$20/ft2c *
-
V X*10/ftc"	
-

— 1
1,1,
sc
UJ
2
0£
CO
6
OC
3
>-

ADDED TO
-
EXISTING STRUCTURE
-
\ V $20/ft2
\ V c

\ 2 \

V \j™c
-

1
i i i		j- ...
1 2 3 4 5
COST OF ELECTRICITY certslVMh
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE XII-10. Economic Analysis for Boise, ID
111-37
-------
(a)
TABLE III-6. Economic Analysis for Twin Falls, ID
A, Percent Energy Supplied by Solar System
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Coat $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
70
59
5}
(b)

2
90
77
71
63

3
92
90
79
73
10
1
40
(b)

(b)

2
70
59
51
(b)

3
77
72
64
54
20
2
40
(b)
(b)
(b)

3
59
45
41
(b)

B. Range
of Optimized Solar
Collector
Areas(ft^)

Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
80
60
330
—

2
155
100
650
490

3
165
155
880
695
10
1
35
—
--
—

2
80
60
330
—

3
100
85
505
370
20
2
35
—
—
—

3
60
40
230
—
(a)	FCHART data is based on information from the National Climatic Center,
Asheville, NC. Twin Falls data should be generally applicable to the
Snake River Valley from Burley north to Mountain Home, ID and can be
used as a guide up the Snake River Basin toward Idaho Falls.
(b)	Less than 40%.
111-38
-------
TWIN FALLS, ID
HOT WATER SYSTEM
ADDED TO
EXISTING STRUCTURE
NEW CONSTRUCTION
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
.ADDED TO
EXISTING STRUCTURE
NEW CONSTRUCTION
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
FIGURE III-ll. Economic Analysis for Twin Falls, ID
III-39
-------
(a)
TABLE 111-1. Economic Analysis for Astoria, OR
A. Percent Energy Supplied by Solar System
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft* Coat cents/kWh Construction Retrofit Construction Retrofit
5
1
50
(b)
44
(b)

2
81
61
61
55

3
96
81
69
63
10
2
50
(b)
44
(b)

3
63
54
55
47
20
2
(b)
(b)
(b)
(b)

3
(b)
(b)
(b)
(b)
2
B. Range of Optimized Solar Collector Areas(ft )
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5	1	70
2	175
3	255
10	2	70
3	105
20	2
3
(a)	FCHART data is based on information from the National Climatic Center,
Asheville, NC. Data from Astoria,- located at the mouth of the Columbia
River, are probably only applicable to the immediate vicinity. However,
it can be used as a guide for the coastal region from Hoquiam, WA south
along the Oregon coast.
(b)	Less than 40%.
2
100	510	400
175	695	550
275
80	400	300
111-40
-------
ASTORIA, OR
HOT WATER SYSTEM
-
NEW CONSTRUCTION
-
# $30/ft2c

/
o
a
ro

\ V C
-
V \ $io/«2
\ N. C
-

-
c

I.I.
2
>
UJ
s
CI
en

ADDED TO
-
EXISTING STRUCTURE
¦
I20JK2
-v
•
-
X.*io/ft2c
-

. 1—
	i	.	i	i
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
-
NEW CONSTRUCTION
-
V v$20/ft2c

\$iom2 \


-
V c

i.i.
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
S
5
Je
2
0£
to
£
QC
14-
12 -
10 -
8 -
6 -
4-
2 -
0 _
~5/ft
ADDED TO
EXISTING STRUCTURE
$20/«.
1 2 3 4 5
COST OF ELECTRICITY certslkWh
FIGURE 111-12. Economic Analysis for Astoria, OR
111-41
-------
TABLE III-8. Economic Analysis for Corvallis, OR
A. Percent Energy Supplied by Solar System
(a)
Hot Water
Hot Water	and Heating
Solar System
Cost 5/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Re tro fit
5
1
56
45
(b)
-------
NEW CONSTRUCTION
CORVALLIS, OR
HOT WATER SYSTEM
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
10
oc
s
>-
ADDED TO
EXISTING STRUCTURE
I
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
NEW CONSTRUCTION
HOT WATER AND HEATING SYSTEM
14
12
10
S
2
*'
a.
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
$5/ff
_L
ADDED TO
EXISTING STRUCTURE
*20/ft2c
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE 111-13. Economic Analysis for Corvallis, OR
111-43
-------
TABLE III-9. Economic Analysis for
Klamath Falls, 0R(a)
A. Percent Energy Supplied by Solar System
Hot Water
Hot Water	and Heatinc
Solar System
Cost S/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
5
1
69

61
53
41

2
80

77
71
64

3
89

89
78
71
10
1
42

(b)
(b)
(b)

2
69

61
53
41

3
78

71
64
56
20
2
42

(b)
(b)
(b)

3
61

46
43
(b)

B. Range of
Optimized Solar
2
Collector Areas(ft )



Hot Water

Hot Water
and Heatinq
Solar System
Cost $/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
5
1
75

60
330
215

2
110

95
610
475

3
150

150
825
630
10
1
35

—
—
—

2
75

60
330
215

3
100

80
490
370
20
2
35

—

--

3
60

40
230
—
(a)	Solar data compiled by the University of Oregon. Klamath Falls is located
in a mountainous area, and data for' it are directly applicable only to the
immediate vicinity.
(b)	Less than 40%.
111-44
-------
14 -
12 -
10 -
8 -
6 -
4 -
2 -
0 -
14 -
12 -
10 -
8 -
6 -
4 -
2 -
0 -
KLAMATH FALLS, OR
HOT WATER SYSTEM
NEW CONSTRUCTION
ADDED TO
EXISTING STRUCTURE
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
ADDED TO
EXISTING STRUCTURE
NEW CONSTRUCTION
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
FIGURE 111-14. Economic Analysis for
Klamath Falls, OR
111-45
-------
TABLE 111-10. Economic Analysis of Medford, OR
(a)
A, Percent Energy Supplied by Solar System
Hot Water
Hot Water
Solar System
Cost $/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
5
1
67
56
43
(b)

2
75
70
61
53

3
86
75
67
62
10
1
41
(b)
(b)
(b)

2
69
56
43
(b)

3
70
69
54
45
20
2
41
(b)
(b)
(b)

3
59
45
(b)
(b)

B. Range of
2
Optimized Solar Collector Areas(ft )



Hot Water
Hot Water
and Heating
Solar System
Cost $/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
5
1
75
55
225
—

2
105
85
4 70
345

3
165
10 5
595
495
10
1
35
—
—
--

2
75
55
225
—

3
85
80
350
250
20
2
3
35
60
40
--
--
(a)	Solar data compiled by the Universi-ty of Oregon. Medford data are probably
directly applicable only in the immedieate area, but the curves can be used
as a guide for the valley region from Grants Pass southeast to Ashland.
(b)	Less than 40%.
111-46
-------
MEDFORD, OR
HOT WATER SYSTEM
NEW CONSTRUCTION
12 3 4 5
COST OF ELECTRICITY cents/kWh
S
Q£
CO
£
UO
Q£
S
>-
14 -
12 -
10
8 -
6 -
4 -
_L
ADDED TO
EXISTING STRUCTURE
_L
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
NEW CONSTRUCTION
1 2 3 4 5
COST OF ELECTRIC) TY cenlilkm
5
2
5
at
CQ
6
14-
12 -
10 -
8 -
6 -
4 -
2 -
0 _
ADDED TO
EXISTING STRUCTURE
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE 111-15. Economic Analysis of Medford, OR
111-47
-------
TABLE III-ll. Economic Analysis of
Friday Harbor, WA^a)
A. Percent Energy Supplied by Solar System
Hot Water
Hot Water
Solar System
Cost $/ft2
Energy
Cost cents/kWh
New
Construction
Retrof it
New
Construction
Retrofit
5
1
54
44
45
(b)

2
69
64
61
54

3
93
78
68
63
10
2
54
44
45
(b)

3
64
56
55
47
20
3
44
(b)
(b)
(b)

B. Range of
2
Optimized Solar Collector Areas(ft )



Hot Water
Hot Water
and Heating
Solar System
Cost $/ft2
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
5
1
70
50
265
—

2
115
95
485
370

3
245
155
660
520
10
2
70
50
265
—

3
95
75
375
285
20
3
50
—
—
—
(a)	Solar data compiled by the University of Oregon. Because of its location
in the San Juan Islands, where local topography can have very significant
effects, data from this station are probably applicable only in the immediate
vicinity of the town itself. However, the curves can be used as a guide for
the entire San Juan Islands region.
(b)	Less than 40%.
111-48
-------
14 -
12 -
10 -
8 -
6 -
4 -
2 -
0 -
14 -
12 -
10 -
8 -
6 -
4 -
2 -
0 -
FRIDAY HARBOR. WA
HOT WATER SYSTEM
NEW CONSTRUCTION
ADDED TO
EXISTING STRUCTURE
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
ADDED TO
EXISTING STRUCTURE
NEW CONSTRUCTION
COST OF ELECTRICITY cents/kWh
COST OF ELECTRICITY cents/kWh
FIGURE 111-16. Economic Analysis of
Friday Harbor, WA
111-49
-------
TABLE 111-12. Economic Analysis of Pullman, WA^3^
A. Percent Energy Supplied by Solar System
Hot Mater
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
68
57
49
(b)

2
77
73
68
61

3
90
79
76
70
10
1
42
(b)
(b)
(b)

2
68
57
49
(b)

3
75
68
62
52
20
2
42
(b)
(b)
(b)

3
60
42
41
(b)
2
B. Range of Optimized Solar Collector Areas(ft )
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	Hew
Cost $/ft^ Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
75
55
315
--

2
105
90
630
490

3
170
115
870
675
10
1
35
—
--
—

2
75
55
315
—

3
95
75
500
355
20
2
35
—
—
—

3
60
40
230

(a)	FCHART data based on information from the National Climatic Center,
Asheville, NC. Pullman is located-in a fairly small valley and data
for it are probably directly applicable only to the immediate surrounding
area.
(b)	Leas than 40%.
111-50
-------
PULLMAN, WA
HOT WATER SYSTEM
NEW CONSTRUCTION
14
ADDED TO
\ \

EXISTING STRUCTURE
\ \ \«0/f»2
12
v \*30/ft2
\ $20/fA \ c

\ \ C
- %mA c\ \.
10
\$20/ft2 ^
¦ \ V
UJ
3 8
\ \tml
\ ^	
OC
°P
\ \
' 1
4*
O
7
? 6
CO
<
i5ltt cV
-
^ 4
	
-
2
-
i.i,
0
i.i.
1 2 3 4 5

1 2 3 4 5
COST OF ELECTRICITY cents/kWh

COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
NEW CONSTRUCTION
14
ADDED TO


EXISTING STRUCTURE
-
12
-
\$20/ft2 tm*2c

¦
\ x. C *
10
-
\ \ $iom2
§
7 mn2c
\ \ ^—
£ .
s 8
\*mc .
~5 m \
at
GO
\

£ 6


IS)
ac
\»5/ft2c
^—
s

-
" 4
"
-
2
-
1 1 1 1 1
0
i.i,
1 2 3 4 5

1 2 3 4 5
COST OF ELECTRICITY cents/kWh

COST OF ELECTRICITY cents/kWh
FIGURE 111-17. Economic Analysis of Pullman, WA
111-51
-------
( cil)
TABLE 111-13. Economic Analysis of Richland, WA
A. Percent Energy Supplied by Solar System
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost ?/ft2 Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
69
61
42
(b)

2
78
73
60
54

3
92
79
68
61
10
1
42
(b)
(b)
(b)

2
69
61
42
(b)

3
73
71
55
44
20
2
42
(b)
(b)
(b>

3
61
47
(b)
(b)

B. Range
of Optimized Solar Collector
Areas(ft2)

Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft2 Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
75
60
2 30
—

2
105
85
480
370

3
190
110
6 75
500
10
1
35
—
—
—

2
75
60
230
--

3
85
80
385
255
20
2
35
—
—
—

3
60
40
—
—
(a)	Solar data compiled by the Hanford Project Meteorological Station.
Richland data are recorded on the Hanford Project and should be
applicable to most of the southern Columbia River Basin north of the
Wallula Gap.
(b)	Less than 40%.
111-52
-------
RICHLAND, WA
HOT WATER SYSTEM
-
NEW CONSTRUCTION
\
\ \$30/ft2c



v20/ftVV
- \


\$10/ft2c\.


C


i i i i..
12 3 4 5
COST OF ELECTRICITY centsfkWh
14
12
10 -
*
s
ce
oo
? 6
tsi
a
3
>-
4 -
2
0
ADDED TO
EXISTING STRUCTURE
_L
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
NEW CONSTRUCTION
*
3
Q£
bc
3

ADDED TO
-
EXISTING STRUCTURE
-
V *10/ft2




i
i, < i i. ...
1 2 3 4 5
COST OF ELECTRICITY ants/HWh
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE 111-18, Economic Analysis of Richland, WA
111-53
-------
TABLE 111-14. Economic Analysis for Seattle, WA
A. Percent Energy Supplied by Solar System
(a)
10
20
Solar Systei
Cost $/ft2
$/ft
5
10
20
Hot Water
Solar System
Cost $/ft2
Hot Water
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
1
47
(b)
(b)
(b)
2
74
58
50
43
3
97
77
57
51
2
47
(b)
(b)
(b)
3
58
51
43
(b)
3
(b)
(b)
(b)
(b)
B. Range of
2
Optimized Solar Collector Areas(ft )


Hot Water
Hot Water
and Heating
Energy
Cost cents/kWh
New
Construction
Retrofit
New
Construction
Retrofit
1
65
—
—
—
2
160
95
380
427
3
260
170
545
513
2
65
—
—
—
3
95
75
290
—
3
__



(a)	FCHART data baBed on information from the National Climatic Center,
Asheville, KC. The Seattle station is located at the Seattle-Tacoma
International Airport and, although directly applicable only to the
immediate area, can be used as a guide for the Puget Sound area from
Everett south to Tacoma.
(b)	Less than 40%.
Ill-54
-------
SEATTLE, WA
HOT WATER SYSTEM
NEW CONSTRUCTION
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
14
12
3
>
UJ
s
a:
cp
o
H-
J*)
Q£
3
>¦
10

ADDED TO
_
EXISTING STRUCTURE
-




c
1
1 > I i
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
NEW CONSTRUCTION
14
ADDED TO


EXISTING STRUCTURE
-
12
-

10


z


UJ
>
UJ
\*!0/«2c

a 8
\
\«/«2c
oc
GO
& A
it 6


t/»

	-	
oc
•
-
S 4
-
-
2
-
i.i,
0
	1	1	1	1	1	
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE 111-19. Economic Analysis of Seattle, WA
111-55
-------
TABLE 111-15. Economic Analysis of Spokane, WA^3^
A. Percent Energy Supplied by Solar System
Hot Water
	Hot Water	 	and Heating	
Solar System	Energy	New	New
Cost $/ft* Cost cents/kWh Construction Retrofit Construction Retrofit
5
1
66
55
45
-------
SPOKANE, WA
HOT WATER SYSTEM
MEW CONSTRUCTION
1 2 3 4 5
COST OF ELECTRICITY centsfkWh
S
>
UJ
S
QC
°P
0
h—
1
CO
Od
a
V
14 -
12
10
ADDED TO
EXISTING STRUCTURE
*30/ft'
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
HOT WATER AND HEATING SYSTEM
NEW CONSTRUCTION
2
~£
(/>
0£
5
>

ADDED TO
-
EXISTING STRUCTURE
-
$20/ft2
*
• c
-

-

'
i... i . i i
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
1 2 3 4 5
COST OF ELECTRICITY cents/kWh
FIGURE 111-20. Economic Analysis of Spokane, WA
111-57
-------
Conclusions
Currently passive solar space heating systems and
active swimming pool heating systems appear to be the most
cost effective application of solar heating in the Northwest.
The application of passive techniques will be limited in
most cases to new construction. Active solar space and
water heating systems are currently marginally cost effective
in the Northwest. In areas with higher energy costs the
lower cost solar systems are competitive. It does not
appear that the solar/heat pump combination studied will be
cost effective in the immediate future.
111-58
-------
References
1.	J. F. Kreider and F. Kreith, Solar Heating and
Cooling - Engineering, Practical Design, and
Economics. McGraw-Hill, NY, 19 76.
2.	J. A. Duffie and W. A. Beckman, Solar Energy Ther-
mal Processes. Wiley, 19 74.
3.	ERDA1s Pacific Regional Solar Heating Handbook.
ERDA San Francisco Operations Office, 1976.
4.	Solar Dv. ailing Design Handbook. U.S. Department
of Housing and Urban Development, 1976.
5.	E. Mazria, M. S. Baker and F. C. Wessling, "Predic-
ting the Performance of Passive Solar Heated Build-
ings." Presented at the International Solar Energy
Society Conference, Orlando, FL, 19 77.
6.	J. D. Balcomb, J. C. Hedstrom and R. D. McFarland,
Passive Solar Heating of Buildings. Los Alamos
Scientific Laboratory, Los Alamos, NM, 1977.
7.	Northwest Energy Policy Project - Energy Conserva-
tion Policy Evaluation. Environmental Research
Center, Washington State University, Pullman, WA,
1977.
8.	An Economic Analysis of Solar Water and Space Heating.
The Mitre Corporation, ERDA Contract E(49-18)2322,
1976.
9.	W. A. Beckman, J. A. Duffie, and S. A. Klein,
"Simulation of Solar Heating Systems," Applications
of Solar Energy for Heating and Cooling of Buildings.
ASHRAE, NY, 19 77.
10.	R. P. Stromberg and S. D. Woodall, Passive Solar
Buildings: A Compilation of Data and Results.
SAND77-1204, Sandia Laboratory, Albuquerque, NM,
1977.
11.	E. Mazria, "The Performance of Passive Solar Heated
Buildings in the Pacific Northwest," Presented at
"Solar 7 7", Portland, OR, 19 77.
111-59
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12.	M. S. Baker and J. Reynolds, Insolation on South
Facing Tilted Surfaces: Pacific Northwest Locations.
University of Oregon Center for Environmental
Research, 19 75.
13.	Northwest Energy Policy Project, Energy Conservation
Policy Evaluation Volume II; Detailed Report of
Analyses. Environmental Research Center, Washington
State University, Pullman, WA, 1977.
111-60
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CHAPTER IV
THE IMPACT OF WIDESPREAD SOLAR DEVELOPMENT
ENERGY SUPPLY UTILITIES AND HEATING FUEL DEALERS
Prepared By
Terry M. Dolan
U.S. Department of Energy
Region X
Seattle, Washington
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Introduction
In this chapter, some of the consequences of "widespread
solar development"* as they relate to the three major sources
of conventional heating energy	gas, oil, and electricity	
will be examined. Quantification of the exact magnitude of
these consequences has not been attempted because of several
uncertainties surrounding conventional energy supply planning
as well as uncertainty about the rate of solar development.
However, several solar heating scenarios have been postulated
and corresponding impacts on utility loads and capacities
have been calculated. This chapter also contains a discussion
of how utility rate structures affect, and are affected by,
solar space and water heating development.
It has been generally believed that widespread development of
solar space and water heating could impact (i.e., lower) the
load factors** of Northwest gas and electric utilities; a
major part of this chapter is devoted to examining the
* For purposes of analysis, we have used the following rates
of conversion as representing "widespread solar development":
(a) the total number of solar space heating systems will
equal 50 percent of the conventional home heating systems
that were in existence in 1976, (b) the total number of solar
water heating systems will equal 80 percent of the conventional
home water heating systems that were in existence in 1976.
** "Load factor" is the ratio of average load carried by an
electric or gas utility to its peak load. A low (or "poor")
load factor means that a utility has high peaks relative
to its average load and this results in inherent inefficiencies.
IV-1
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significance of such an impact. The reason for an impact is
simply that during the coldest and darkest days of winter,
when the output of a typical residential solar system is not
great enough to meet the heating load* of the building,
conventional heating systems would be required to take up
the slack. Thus, the gas and electric utilities serving
solar heated buildings would be required to have capacity to
meet this need. However, during temperate days, solar
heating might be sufficient to meet (or substantially meet)
heating needs, and utility load would be reduced. Thus,
seasonal utility load problems would be exacerbated since
energy from solar power is available least when needed most,
and vice versa.
Associated impacts of a reduced utility load factor are
decreased revenue (assuming constant utility rates), and
potential difficulty by the utility in financing the supply
capacity necessary to meet peak winter demand.**
* See chapters II and III for information concerning winter
insolation and the amount of heating load that could be
supplied by solar systems.
** This is because utility annual revenues are a function of
the amount of energy sold throughout the year and solar
development would tend to reduce the revenues. Further,
utilities must construct sufficient generating capacity
to meet peak load irrespective of average demand. The
need for this capacity (and the associated requirement for
large amounts of capital investment) is not likely to be
significantly lessened by solar development.
IV-2
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Pacific Northwest energy supply utilities have some unique
characteristics. For example, while electric utilities in
the rest of the United States experience a summer demand
peak, areas served by the Northwest Power Pool* (except for
certain areas in Eastern Washington, Eastern Oregon, and
Idaho) have a winter peak. Also, the Northwest's extensive
hydrogenerating capacity allows more rapid and efficient
response to variations in electrical demand than is possible
with thermal generating systems.
Approximately-two thirds of the natural gas used in the
Pacific Northwest is supplied under contract from Canada via
pipeline at a negotiated price. The six Northwest gas
utilities have large storage capacities and, to date, no
shortages have been experienced by residential customers.
By comparison, in the rest of the United States, most gas
customers are supplied by interstate pipeline with gas
produced in the Southern United States. During very cold
winter periods, when demand is high, shortages in interstate
residential gas supplies have been experienced. Like
electricity, peak demand for natural gas and heating oil in
the Northwest occurs during the colder winter months.
* The Northwest Power Pool (NWPP) is an association of all
Northwest electricity generating utilities. The NWPP
utilizes an extensive grid of transmission lines within
the Northwest to exchange energy between utilities to meet
local shortages and dispose of any local excesses.
IV-3
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Nationally, some innovative utility rate structures have
been proposed to stimulate solar development. Such concepts
as interruptible residential service and time-of-year rates
have potential application to utilities in other parts of
the country that experience a summer peak; however, those
particular structures are not applicable to the energy
demand characteristics of the Northwest. In this chapter we
also consider some of the problems associated with development
of an equitable rate structure that would encourage solar
development while not adversely affecting the energy supply
utilities.
Heating Oil Impacts
While it is generally recognized that heating oil sales
fluctuate seasonally, heating oil demand does not experience
the short term (day-to-day) demand variations that gas and
electricity supplies do. Fuel oil is usually delivered to
and stored at the end-use location, and in quantities large
enough to suppress variation in consumption rates. For
example, a homeowner may purchase 300 gallons of heating oil
in the fall, refill the portion used during late winter and
not purchase any more oil until the next fall. Large scale
IV-4
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solar heating development, with oil heating backup, would
tend to reduce the quantity of oil consumed but would not
substantially affect oil dealers' ability to provide adequate
service to the public.
Natural Gas Impacts
The six natural gas utilities operating within the geographical
boundaries of Washington, Oregon, and Idaho are all supplied
solely by one interstate gas supply company, the Northwest
Pipeline Corporation. Total transmission capacity of
Northwest Pipeline's main line system is approximately 1.4 5
billion cubic feet of natural gas per day.^
The Northwest Pipeline obtains its gas supplies from domestic
and foreign sources. Approximately two-thirds is supplied
by Canadian sources and the remainder by domestic sources.
About 7 5% of its total annual sales occur in Washington,
Oregon, and Idaho.
IV-5
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The Northwest Pipeline's gas supply volumes for 1975 are
presented in Table IV-1. An examination of Table IV-1
reveals a maximum variation in demand during 1976 of 26
percent (April/August).
The contracts between Northwest Pipeline and the Canadian
gas producers are known as "contract agreements." These
agreements do not specify delivery of a given amount of gas
for a given period of time. Rather, the agreements bind the
producers to supply u£ to a specified amount (upper bound)
but do not require Northwest Pipeline to buy any fixed
minimum amount (lower bound) of gas. This gives Northwest
Pipeline considerable flexibility in matching gas supply
with demand.
The relatively uniform supply rate of gas to Northwest
Pipeline shown in Table IV-1 is due in part to the pipeline
system's storage capacity. The Northwest Pipeline Corporation
owns and operates a liquified natural gas (LNG) storage
plant for peak shaving* purposes. This LNG plant, located
at Plymouth, Washington, liquifies excess pipeline natural
* "Peak shaving" is a term used to	describe the use of standby
gas storage/supply facilities to	assist in meeting high
demand situations. Although the	total peak is not really
reduced, the contribution of the	standby facilities reduces
the peak that must be met by the	rest of the utility system.
IV-6
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TABLE IV-1
Northwest Pipeline Corporation
Supply Averages - 1975
Month
Average Supply
(Billion cu.ft. per day)
January
1.045
February
1.117
March
1.118
April
1.239
May
1.221
June
1.167
July
1.055
August
0.977
September
1.033
October
1.132
November
1.173
December
1.130
SOURCE; "Analysis of the Demand for Natural Gas,"
FEA, Region X, March 1977
IV- 7
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gas during milder months of each year. In winter, the LNG
is converted back into its gaseous form and delivered to
Northwest Pipeline customers on days of high demand.
Northwest Pipeline also participates with two of its distri-
bution company customers, Washington Natural Gas Company and
the Washington Water Power Company, in the ownership and
operation of the Jackson Prairie Storage Project at Chehalis,
Washington. Storage of natural gas allows Northwest Pipeline
to purchase gas at a relatively uniform rate throughout the
year, store it, and then resell it as demand requires.
Skidmore, Owings & Merrill (SOM) reported that new construction
residential natural gas space heating requirements in Portland,
Oregon average 1015 therms* per year for single family
units, and 400 therms per year for multi-family units.^ SOM
also reported that new construction water heating requirements
for single family and multi-family units average 300 therms
and 240 therms per year, respectively.2 For purposes of
analysis we will assume that natural gas space and water
heating requirements are uniform for housing units through-
out the region. It is believed that this approximation will
* One therm = 100 ft^ of natural gas = 100,000 Btu's
IV-8
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not significantly affect the overall conclusions of this
chapter. Energy consumption for water heating is primarily
a function of hot water usage and it is reasonable to expect
that a family in Boise, Idaho (for example) will consume
approximately the same amount of water heating energy as it
would in Portland, Oregon. On the other hand, space heating
energy requirements are a function of heating degree days.
However, since the majority of the region's population lives
west of the Cascade Mountains in a climate similar to Portland,
it seems a reasonable assumption that Portland area data
will provide a good approximation for overall Pacific Northwest
impact calculations.
U.S. Department of Housing and Urban Development data3
indicate that there are over 500,000 housing units space-
heated by natural gas and over 220,000 housing units with
water heated by natural gas within Washington, Oregon, and
Idaho.
To obtain an estimate of the amount of natural gas that
might be displaced by widespread application of solar systems
in residences, we must make several assumptions. For a
typical house we will assume that solar energy could supply
50 percent of annual space heating needs and 80 percent of
IV-9
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annual water heating needs. Next, we must make an estimate
of the "average" natural gas consumption.* If we assume
that gas for water heating is used uniformly during the
entire year, we can calculate the average daily decrease in
demand per household conversion to solar water heating:
Decreased Daily
Demand Per
Single Family Unit

Annual Gas Consumption
For Water Heating
365 days/yr
[
30,000 ft3/y
365 days/y
Fl
1
J Percent of
I Water Heat
Supplied by Solar
3
80%
66 ft^/day
Decreased Daily
Demand Per	=
Multiple Family Unit
[¦
Annual Gas Consumption
For Water Heating
36 5 days/yr
[24,000 ft3/yrj x
365 days/yr j
x
80%
Percent of
Water Heat
Supplied by Solar
53 ft^/day
* The following calculations are intended to provide "order
of magnitude" approximations of energy use patterns and
utility impacts. Many simplifying assumptions (for example,
an even distribution of gas heating equipment between single-
family and multi-family housing) will be made. It is
believed that these assumptions will not significantly affect
the final conclusions of this chapter.
IV-10
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Given the example of 110,000 gas water heater conversions*
(50% conversion rate) to solar 	 equally divided between
single and multi-family housing units 	 the total daily
average decreased gas demand in the Pacific Northwest would
be:
Similarly, to obtain an estimate of the amount of natural
gas that might be displaced by solar space heating, we assume
a six month heating season and calculate the decreased average
daily demand as follows:
* This is simply an example of widespread conversion and is
not intended as a projection of what may actually occur in
the near future.
Total Decreased
Daily Water Heating
Gas Demand
# Single Family
Conversions
Decreased Daily
Single Family
Demand
+
# Multiple Family
Conversions
Decreased Daily
Multiple Family
Demand
£55,000 units x 66 ft^/da^
£55,000 units x 53 ft3/dayj
{3.6 + 2.9} million ft3/day
6.5 million ft-yday
+
IV-11
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Decreased Daily
Demand Per
Single Family Unit
Annual Gas Consumption
For Space Heating
180 days/yr
x
Percent of
Space Heat
Supplied by Solar
1101, 500 ft3/yr*1 v
180 days/yr J
50%
282 ft /day
Decreased Daily
Demand Per	=
Multiple Family Unit
Annual Gas Consumption
For Space Heating
180 days/yr
x
Percent of
Space Heat
Supplied by Solar
4 0, 000 ft3/yr 1 x
18 0 days/yr J
50%
111 ft3/day
Because solar space heating conversions are more costly than
water heating conversions (because more collector area,
piping, etc., is required) the percentage of conversion is
likely to be smaller for the former. Therefore, we will
assume a space heating conversion of 100,000 units* 	 20%
of total gas space heating units 	 for this example. We
will also assume that half the space heat conversions will
occur in single family units and half in multiple family
units.
* This is simply an example of widespread conversion and
is not intended as a projection of what may actually
occur in the near future.
IV-12
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Decreased space heating average daily demand in the Pacific
Northwest would be:
Now, if we assume a "worst case" situation, namely, that
under peak winter load conditions solar energy does not
contribute to space or water heating needs, we can calculate
the extent of potential impact on utilities (i.e., potential
decrease in load factor) caused by widespread solar development:
Decreased Daily
Single Family
Demand
# Single Family
Conversions
Decreased Daily
Space Heating
Gas Demand
+
Decreased Daily
Multiple Family
Demand
# Multiple Family
Conversions
£50,000 units x 282 ft^/day^
(50,000 units x 111 ft3/day]
(l4.1 + 5.5^ million ft3/day
19.6 million ftyday
IV-13
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Load Factor
Decrease due to = Estimated Decreased Average Demand x iqO%
Solar Development	Peak Demand
= 6.5 + 19.6 million ft3/day v inna
1.24 billion ft^/day*
2.1 Percent Decrease
This calculated decrease in load factor is an overall average
for all Northwest gas utilities supplied by the Northwest
Pipeline Corporation. It is recognized that some individual
utilities may experience greater localized load factor
decreases. The above calculations are intended as "order of
magnitude" illustrations based on rough assumptions (such as
50 percent conversion to solar water heating). Nonetheless,
it seems reasonable to infer from this calculation that the
load factor decrease likely to result from "widespread solar
development" is relatively small when compared to the 21
percent** variation in monthly load indicated by Table IV-1.
* Peak demand (rounded to two significant figures) taken
from Table IV-1. The peak demand occurred during the
month of April.
** % variation = high s
upply month-low supply month x ioo%
nigh supply montn
1.239 - 0.977 x 100%
1.239
°-262 x 100%
1.239
21%
IV-14
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While a widespread conversion to solar water and space
heating would tend to lower overall consumption of natural
gas (save energy) and thereby reduce gas utility revenues in
the Northwest, it appears that such a shift to solar (with
gas as backup) would not substantially reduce overall load
factor or gas utilities' ability to provide adequate service
to the public. Indeed, increased conservation will cause
the available natural gas to last longer and, therefore,
lengthen the period during which the gas utilities have gas
to sell. Such an impact is consistent with the serious
conservation efforts already being undertaken by the gas
utilities in the Pacific Northwest.
Electricity Impacts
As of December 31, 1975, the nameplate capacity of electrical
generating plants within the States of Washington, Idaho,
and Oregon totaled 26,199 MWe.4 Of this, 21,697 MWe (83
percent) represent hydropower, 2,016 MWe (8 percent) nuclear
power, 1,300 MWe (5 percent) coal power, and the remaining
1,204 MWe are oil or gas powered. The coal and nuclear
powered generating plants are used to meet base load demand;
the oil and gas plants are brought "on line" only during
periods of maximum (peak) demand; the hydroelectric plants
IV-15
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are used for both base load and peaking purposes. Unlike
natural gas and oil, once electricity is generated within a
utility system it cannot be (practically) stored. A large
portion of the electrical generating load in the Pacific
Northwest is used for electric space heating. Space heating
requirements are a function of the weather, and there is a
large seasonal variation in demand in the Pacific Northwest;
the peak demand (except for certain areas in eastern
Washington, eastern Oregon, and Idaho) occurs during the
winter.
Average and peak demands for electrical energy supplied by
the Northwest Power Pool between July 1975 and June 1976 are
tabulated in Table IV-2.
Skidmore, Owings, and Merrill (SOM) reported2 that new
construction residential electric space heating requirements
in Portland, Oregon average 14,700 KWH per year for single
family units and 5,800 KWH per year for multi-family units.
SOM also reported"^ that new construction water heating
requirements for single family and multi-family units average
5,000 KWH per year and 3,500 KWH per year, respectively.
For purposes of analysis, we will assume that electric space
and water heating requirements are uniform for housing units
throughout the region. It is believed that this approximation
IV-16
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TABLE IV-2
Northwest Power
Pool Monthly Loads
(MWe)
Month
Average
Demand
Peak
Demand
Load Factor*
July 1975
17,166
22,078
78%
August
16,475
21,079
78%
September
16,483
20,863
79%
October
18,170
24,394
74%
November
20,289
26,817
76%
December
20,832
27,685
75%
January 1976
21,490
27,093
79%
February
21,817
28,439
77%
March
21,288
27,589
77%
April
19,521
25,405
77%
May
18,670
23,921
78%
June
19,283
24,640
78%
ANNUAL
19,290
28,439
68%
SOURCE; Northwest Power Pool "Operations Review" for 1975
pp. C-6 and C-7.
* Computed as ^eak^Demand"3 x 100% = Load Factor;
not included in "Operations Review."
IV-17
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will not significantly affect the overall conclusions of
this chapter. Energy consumption for water heating is
primarily a function of hot water usage and it is reasonable
to expect that a family in Boise, Idaho (for example) will
consume approximately the same amount of water heating
energy as it would in Portland, Oregon. On the other hand,
space heating energy requirements are a function of heating
degree days. However, since the majority of the region's
population lives west of the Cascade Mountains in a climate
similar to Portland, it seems a reasonable assumption that
the Portland area data will provide a good approximation for
overall Pacific Northwest impact calculations.
U.S. Department of Housing and Urban Development data^
indicate that there are approximately 600,000 housing units
with electric space heating and 1.8 million units with
electric water heating within Washington, Oregon, and Idaho.
To obtain an estimate of the amount of electricity that
might be displaced by widespread application of solar space
and water heating, we must make several assumptions. For a
typical house we will assume that solar energy could supply
50 percent of annual space heating needs and 80 percent of
water heating needs. Next, we must make an estimate of the
IV-18
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"average" electrical consumption.* If we assume that elec-
tricity for water heating is used uniformly during the entire
year, we can calculate the average daily decrease in demand
per household conversion to solar water heating:
Decreased Daily
Demand Per
Single Family Unit
Annual Electricity
Consumption For
Water Heating
365 days/yr
[
x
5,000 KWH/yrl x 80%
365 days/yrj
Percent of
Water Heat
Supplied by Solar
11.0 KWH/day
Decreased Daily =
Demand Per
Multiple Family Unit
Annual Electricity
Consumption For
Water Heating
365 days/yr
t
3,500 KWH/yr
365 days/yr
3-
80%
Percent of
Water Heat
Supplied by Solar
7.7 KWH/day
* The following calculations are intended to provide "order
of magnitude" approximations of energy use patterns and
utility impacts. Many simplifying assumptions (for example,
an even distribution of electric space and water heaters
between single and multi-family housing units) will be made.
It is believed that these assumptions will not significantly
affect the final conclusions of this chapter.
IV-19
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If, for example, 900,000 conversions* (half single family,
half multiple family) were to take place out of the 1.8
million existing electric water heating installations
(50% conversion rate), the decreased daily average water
heating electricity demand in the Pacific Northwest would
be:
Similarly, to obtain an estimate of the amount of electricity
that might be displaced by solar space heating, we assume a
six month heating season and calculate the decreased average
daily demand as follows:
* This is simply an example of widespread conversion and is
not intended as a projection of what may actually occur in
the near future.
Total Decreased
Daily Water Heating
Electricity Demand
# Single Family
Conversions
Decreased Daily
Single Family
Demand
+
# Multiple Family
Conversions
Decreased Daily
Multiple Family
Demand
[450,000 units x 11.0 KWH/day} +
^450,000 units x 7.7 KWH/day]
£4.9 + 3.5[) million KWH/day
8.4 million KWH/day
IV-20
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Decreased Daily
Demand Per
Single Family Unit
Annual Electricity
Consumption For
Space Heating
180 days/yr
x
Percent of
Space Heat
Supplied by Solar
14,700 KWH/yr-l x 5Q%
180 days/yr
4 0.8 KWH/day
Decreased Daily
Demand Per	=
Multiple Family Unit
"Annual Electricity
Consumption For
Space Heating
. 180 days/yr *
x
Percent of
Space Heat
Supplied by Solar
[5,800 KWH/yrj x
180 days/yrj
16.1 KWH/day
50%
Because solar space heating conversions are more costly than
water heating conversions (because more collector area,
piping, etc., is required) the percentage of conversion is
likely to be smaller for the former. Therefore, we will
assume a space heating conversion of 120,000 units* out of
the 600,000 existing electric space heating installations
(20 percent conversion rate) for this example. We will also
* This is simply an example of widespread conversion and is
not intended as a projection of what may actually occur in
the near future.
IV-21
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assume that half the space heat conversions will occur in
single family units and half in multiple family units.
Decreased space heating average daily demand in the Pacific
Northwest would be:
Decreased Daily
Space Heating
Electricity Demand
# Single Family
Conversions
# Multiple Family
Conversions
x
Decreased Daily I
Single Family I +
Demand
Decreased Daily I
Multiple Family
Demand J
^60,000 units x 40.8 KWH/day} +
(60,000 units x 16.1 KWH/dayJ
£2.4 + 1.03 million KWH/day
3.4 million KWH/day
Now, if we assume a "worst case" situation, namely that
under peak load conditions solar energy does not contribute
to space or water heating needs, we can calculate the extent
of potential impact on utilities (i.e., potential decrease
in load factor) caused by widespread solar development:
IV-2 2
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Load Factor	Decreased Average Demand x ^qq%
Decrease due to =	Peak Demand
Solar Development
8.4 + 3.4 million KWH/day x l day x ioq%
27,685 MWe*	24 hr
1.8 Percent Decrease
This calculated load factor decrease is an overall average
for the entire Northwest Power Pool. It is recognized that
some individual utility components of the Pool that have
primarily residential base loads will experience greater
localized load factor decreases. It is also recognized that
daily peak heating demand during December or January will
exceed the "average decreased demand" used in the calculation.
Finally/ it should be remembered that the above calculations
are intended as "order of magnitude" illustrations based on
rough assumptions (such as 50 percent conversion to solar
water heating).** Nonetheless, it seems reasonable to infer
from this calculation that the load factor decrease likely
to result from "widespread solar development" is relatively
* Peak demand for December, 1975 (taken from Table IV-2).
December was selected because it is a month which repre-
sents a "worst case" situation: it has the least available
solar energy and is also one of the coldest winter heating
months i
** A more sophisticated analysis of solar impacts on electric
supply utilities is currently being conducted by the
Electric Power Research Institute. Their report is expected
to be available by summer of 1978.
IV-23
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small when compared to the 68% annual load factor or the 5%
maximum variation between monthly load factors shown in
Table IV-2.
From the above calculation, it is apparent that a widespread
conversion to solar space and water heating would reduce
overall consumption of electricity (save energy) and, there-
fore, reduce utility revenues in the Northwest. It also
appears that such a shift to solar (with electricity as
backup) would not substantially reduce electric supply
utilities' overall load factors or their ability to provide
adequate service to the public.
Rate Structures
An energy supply utility rate structure in the Northwest that
would both encourage solar development and provide the
utility with a fair return on invested capital appears
difficult to devise. Several factors contribute to the
price that a utility charges its customers for delivered
energy. Among these are both fixed costs for such things as
generating equipment (or gas wells), distribution systems,
and meters, as well as the variable cost of fuel. The
IV-24
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installation of a solar heating system (with conventional
utility-supplied energy backup) helps the utility reduce its
variable fuel cost 	 but does nothing to reduce fixed
capital equipment costs of providing service to the customer.
In the event of widespread solar development, energy supply
utilities may attempt to amend their rate structures with
the intention of ameliorating the added economic burden
perceived to be caused by solar energy use (with conventional
energy supply as backup). One way to do this is to utilize
a rate structure which would more accurately reflect the
actual fixed charges of providing service. At present, most
rates are structured so that the charge for providing service
covers only part of the true cost, with the remainder of
that cost averaged into the energy charge. If the charge
for providing service were increased to reflect true cost,
the economic impact on the utility due to widespread solar
development would probably be significantly lessened.
The only residential utility rate structure known to the
author that was designed to compensate the supply utility
for loss of revenue because of solar heating development was
approved by Colorado State Utilities Commission and became
effective February 9, 1976. An electricity supply utility,
the Public Service Company of Colorado (PSCo), obtained
IV-2 5
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approval to charge residential customers who use electricity
as their primary source of backup heating for solar equipment
a "demand/energy" rate. To understand the effect of this
"demand/energy" rate, we should compare it to more conventional
rate structures. In the Northwest, typical conventional
rate structures involve a small fixed service charge of one
to three dollars to cover such things as metering and utility
administrative costs. In addition, an energy charge is
levied for the amount of electricity or gas used. When such
relatively low fixed charges prevail, the homeowner's
monthly bill is roughly proportional to the amount of energy
consumed. The "demand/energy" rate adopted in Colorado
bases the charge for electrical service on both the total
kilowatt-hours used (energy), and the maximum electrical
load (demand) during any 15 minute period during the billing
period. This charge serves to recover the utility's fixed
cost of providing basic service to the customer separately
from the cost of the actual energy consumed.
The cost effect that the "demand/energy" rate structure has
on a homeowner with a solar space heating system can be
shown by performing parallel utility charge calculations for
identical family residences, with and without solar heating
systems. Table IV-3 is such a comparison for two electrically
IV-26
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TABLE IV-3
Comparison of Electrical Energy Cost For
"All-Electric" and "7 0 Percent Solar" Homes
in Denver, Colorado
Heating Costs
All Electric	70% Solar
Month
Typical
Rate
Demand/Energy
Rate
Typical
Rate
Demand/Energy
Rate
January
$110
$ 82
$ 76
$ 69
February
82
63
46
51
March
72
60
35
46
April
62
51
32
40
May
39
42
29
38
June
34
40
29
38
July
29
38
29
38
August
30
38
29
38
September
43
43
29
38
October
54
47
29
38
November
80
63
47
51
December
95
69
63
56
ANNUAL
$730
$636
$473
$541
SOURCE: "Demand Electric Rates: A New Problem and Challenge
for Solar Heating," ASHRAE Journal, Vol. 19, No. 1,
January 1977. All costs rounded to the nearest dollar.
IV-27
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heated homes (with and without solar) that each lose 10,000
Btu/degree day.5 This approximates a well-insulated 2000
square foot house. Denver, Colorado weather data and utility
rates were used.
An examination of Table IV-3 indicates that an "all-electric"
heating system in the prototypical home costs less to operate
under the "demand/energy" rate structure than under the
conventional rate structure. In the case of the solar home,
however, the "demand/energy" rate resulted in much higher
annual utility charges. The solar heated home obtained
7 0 percent of its energy needs from the sun—but only saved
15 percent of its energy costs.
While the magnitude of the results will vary depending on
geography, climate, housing type, fuel type, utility, etc.,
the overall effect of this type of rate structure may well
be the same whenever it is in use 	 potential residential
solar development may will be seriously deterred.
Conclusions
1. The widespread development of residential solar space
and water heating would tend to lower overall consumption
IV-28
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of conventional energy sources (oil, gas, and electricity)
and, thus, save energy. It appears that such a conversion
to solar heating would not substantially reduce overall
utility load factors or the utilities' ability to
provide adequate service to the public.
2. "Demand/energy" utility rate structures, similar to
that adopted in Colorado, may act to discourage solar
development because large reductions in energy consumption
do not result in proportional reductions in energy
costs. Hence, savings may not be sufficiently attractive
economically to justify the often large capital investment
required for solar systems.
IV-2 9
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References
1. "Analysis of the Demand for Natural Gas," FEA Region X,
March 1977.
2. "Residential Conservation Choices," Portland Energy
Conservation Project, Skidmore, Owings and Merrill,
June 1977.
3. Per data provided by Department of Housing and Urban
Development, Region X, Regional Economist.
4. "Northwest Energy Policy Project, Conventional Energy
Resources," Study Module III-A, Northwest Regional
Commission, May 1977.
5. "Demand Electric Rates: A New Problem and Challenge
for Solar Heating," ASHRAE Journal, Vol. 19, No. 1,
January 1977.
IV-30
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CHAPTER V
LEGAL ISSUES AFFECTING SOLAR ENERGY DEVELOPMENT
Prepared By
Steven W. Anderson and Michael Monroe
U.S. Department of Energy
Region X
Seattle, Washington
-------
Introduction
The purpose of the following analysis is to examine various
private and public law doctrines which may affect a solar
user's access to sunlight, to point out obstacles to the
widespread use of solar energy, and to suggest changes which
will accomodate and encourage solar energy use.
Right to Light
To the solar energy user, the uninterrupted access to both
overhead sunlight and to sunlight from across adjoining
property is vital. After having made a substantial invest-
ment, the solar energy user cannot afford to run the risk
that his neighbor may build a structure or allow the growth
of vegetation that would cast a significant shadow upon his
solar collectors. The availability of legal protection for
adequate access to sunlight is the major prerequisite to
widespread solar use.
English Common Law protects a landowner's access to light
from directly overhead under a theory of trespass."'" But
this theory affords no protection to the landowner's interest
in access to sunlight travelling diagonally across a neighbor's
land. in order to insure uninterrupted access to lateral
light, other private law doctrines must be considered.
V-l
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Easement
An easement is a property right in which one person has the
right to a limited use or enjoyment of another person's
3
land. The owner of a negative easement can prevent any
activity on the other person's property which would violate
4
the easement. For example, a proposed building that would
violate an easement for light and air could be prevented
from being built.
Depending upon how it arises, an easement may be charac-
terized as either express or implied. Express easements are
explicit mutual promises made between landowners. Implied
easements are created by operation of law, either as a
matter of necessity or, in the case of prescriptive ease-
5
ments, through long usage.
The concept of an implied easement for light and air created
by long usage has not been recognized by American courts,
although a form of this easement has long been recognized in
English law as the Doctrine of Ancient Lights.6 Under the
doctrine, if a person has had uninterrupted use of light for
a number of years, an adjoining landowner can not cause that
7
light to be blocked. The right protects only the amount of
light reasonably necessary for interior lighting, but it
V-2
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gives the homeowner some degree of protection from a neighbor
building a new structure that would block sunlight from his
8
property generally. Early in American history, the courts
rejected the Ancient Lights Doctrine because of the belief
that it would tend to impede the rapid urban growth then
being experienced.^ A Florida case recently affirmed that
the Doctrine of Ancient Lights is not part of the common law
in America.-'-0 Thus, despite his long-term reliance on
lateral sunlight, a landowner has no legal protection
against the construction of a neighboring structure that
blocks that light."*"1
Unlike implied precriptive easements for light and air,
1 7
implied easements of necessity^ are recognized in American
common law. Typically, easements of necessity are created
when an owner conveys part of his property without providing
any means of access. The courts may grant the new owner of
the landlocked property an easement to travel across the
seller's property. The degree of necessity needed to create
this easement varies. In Washington, Oregon, and Idaho the
trend has been to require a reasonable degree of necessity
13
and a past unity of ownership.
The solar energy user would ordinarily be unable to benefit
from the theory of easement by necessity, since he would
V-3
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have to demonstrate some degree of necessity as well as a
past unity of ownership with the adjoining parcels of
14
property. Furthermore, even if an easement by necessity
becomes readily available to solar energy users, the need to
establish the easement through litigation on a case by case
basis would deter most potential solar energy users.
Express easements for light and air are recognized at common
law.^ Mutual agreements can be written to grant an ease-
ment for sunlight to a user of solar energy. However, there
are significant problems associated with using express
easements. The amount of airspace needed to protect access
to lateral sunlight is difficult to define. An overly broad
description of the airspace would place excessive and
unnecessary restrictions on the adjacent property, while
under-inclusive descriptions inadequately protect the solar
energy user. Another problem may be the general reluctance
of some courts to enforce negative easements, because ease-
ments are viewed as preventing a landowner from utilizing
his land fully and have been generally disfavored in American
law. The cost of acquiring a solar easement from a neighbor
may be prohibitive. Neighbors may be reluctant to grant
such easements because of the uncertainty over what potential
land uses they will be giving up. Furthermore, in densely
V-4
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populated urban areas, the potential solar energy user would
have to negotiate with a large number of neighbors where the
value of potential land uses rises sharply. While express
easements offer some assistance in protecting a solar energy
user's access to sunlight, the practical difficulties
suggest that other forms of legal protection are necessary
to supplement the protection afforded to solar energy users
by express easements.
Solar skyspace easements defined by legislation offer
certain advantages over easements that are based entirely on
private negotiations. Easements of this type are discussed
on pages V-21 and V-22.
Restrictive Covenants
Restrictive covenants are mutual promises regarding land use
made between adjoining landowners or made by a developer as
16
part of his development scheme. A deed conveying property
often contains restrictions concerning the character, location,
and minimum cost of any structure to be built on the property.
A developer might include within his deeds to purchasers
mutual promises to refrain from taking various actions
because he believes that this will make his development more
V-5
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attractive to buyers. By accepting the deed a new owner
accepts the mutual promises or covenants. If the new owner
violates some of these covenants, his neighbors can enforce
17
them against him.
It is possible that restrictive covenants could be drafted
to encourage solar energy use, for example, by prohibiting
the construction of neighboring structures that would block
sunlight traveling to a solar collector.
On the other hand, the development of solar power as an
energy source is relatively recent, and the language of
existing covenants may unintentionally bar solar energy use.
Under a restrictive covenant prohibiting "all rooftop air
conditioners and similar structures," a rooftop solar
collector could be viewed as a "similar structure" and may
be barred.
Some developers, in placing a high priority on esthetic
factors, may expressly restrict or bar solar energy systems
because they believe rooftop solar collectors are unat-
tractive. If a potential solar energy user desires to
change a restrictive covenant that bars solar energy systems,
he must obtain the unanimous agreement of all the other
.	18
covenantees who own property withxn the development.
V-6
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Restrictive covenants, then, can encourage or impede the use
of solar energy. At present it appears that many restric-
19
tive covenants are neutral concerning solar energy systems.
Restrictive covenants will be widely used to encourage solar
energy use only if developers come to believe that encouraging
the use of solar energy will make their developments more
marketable. Public interest in solar energy will shape the
developers' attitudes. However, restrictive covenants that
are drafted to specifically encourage use of solar energy
will obviously apply only prospectively and will work best
in new developments.
Nuisance
The nuisance doctrine restricts a property owner's right to
use his property in ways that would unreasonably invade the
rights of his neighbors.^
A private nuisance is a substantial and recurring invasion
21
of another landowner's interests. Whether a particular
invasion is sufficient to constitute nuisance depends upon
2
its effect upon persons of ordinary habits and sensibilities.
A neighbor complaining that a rooftop solar collector is a
nuisance would likely have esthetic considerations as his
V-7
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main basis for complaint. Usually, things that are merely
unsightly or offend a neighbor's esthetic sense do not
23
constitute a nuisance. Glare reflecting from a solar
collector may provide another basis for complaint, but the
inconvenience and annoyance caused by glare would have to be
at a level that is unreasonable for an ordinary person.
Mere inconvenience or the personal idiosyncrasy of a neighbor
will not substantiate an action to abate a nuisance.
On the other hand, it is uncertain whether a solar user
would be able to use a nuisance theory to prevent his
neighbor's structure from casting a shadow across his solar
collector. In order to do so, the solar energy user must
clearly show irreparable injury that cannot be compensated
by money damages. The court must determine, in light of the
hardships suffered by both parties, that the solar energy
user warrants an injunction rather than money damages. The
cost of litigating this uncertain area may, as a practical
matter, limit the use of nuisance theory to encourage solar
development.
Public nuisances are usually defined by ordinances enacted
24
for the protection of the public health, safety, and morals.
A public nuisance is an interference with this public interest.
In order to invoke the protection of public nuisance doctrine,
solar energy must be shown to be such an important energy
V-8
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alternative that interference with private solar collectors
seriously affects the rest of the public. It appears that
there would usually not be sufficient damage, inconvenience,
or annoyance to the general public to constitute a public
nuisance under these circumstances. An attempt in Colorado
Springs to declare trees shading solar collectors to be
25
public nuisances was recently abandoned.
In summary, whether characterized as private or public,
nuisance concepts appear to be neither an impediment nor an
• „ ,	26
aid to solar energy users.
Building Codes and Zoning
Present building codes could delay the widespread use of
residential and commercial solar energy systems.
The authority to promulgate building codes to protect the
public health and safety has traditionally been delegated to
units of local government. Obstacles to the use of solar
energy systems arise in two ways: (1) the content of the
code may impede solar utilization since most codes predate
widespread interest in solar development; and (2) the fact
that legal and political authority for promulgating the
codes lies with local governments may lead to local varia-
tions which inhibit development of a national solar market.
V-9
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There are two basic approaches used to formulate building
27
codes. The first approach is to set up prescriptive
standards which operate by requiring the use of specific
building materials in a certain way. The other approach
establishes performance standards under which any building
technique or material is allowed if it produces the specified
result. While performance criteria allow more flexibility
and readier acceptance of innovative materials and designs,
prescriptive standards are believed to be easier to administer
and have been traditionally used in most municipalities.
Solar builders may encounter problems because their designs
or materials are innovative and do not fall within the
existing prescriptive code. Even though many prescriptive
building codes have provisions allowing equivalent designs
or materials, these provisions have historically been used
sparingly. Very often the cost of special design and
testing requirements is prohibitive. When coupled with the
uncertainty of the permit process, builders are likely to
2 8
become wary of using innovative designs or materials.
Most municipalities have adapted their codes to local needs
with the result that variations in building codes are wide-
29
spread. Variations in the codes and variations in their
enforcement have tended to make building construction a
local industry. Administration of the codes may often be
31
overly cautious and err in favor of conventional wisdom.
V-10
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In attempting to standardize building codes, the
emphasis has been on promoting the work of model code groups
such as the Uniform Building Code, the Basic Building Code,
the National Building Code, and the Southern Building Code.
These codes were drafted primarily by professional groups of
building inspectors, utilizing technical committees of
experts who reflect the views of labor and material suppliers,
3 2
as well as building professionals. Each code is period-
ically updated, usually with an annual supplement. In 1971,
33
the code writing groups combined to publish a joint code.
The Federal government has recently taken the initiative to
formulate building standards that aim to increase energy
34
efficiency in new commercial and residential buildings.
Various demonstration programs are being undertaken in order
to encourage energy conservation, and programs have been
designed to train local building officials so that they will
understand the goals of the new building code standards.
Many states, including Oregon and Washington, have adopted
statewide minimum building codes. Idaho has a minimum
building code which is optional for county and city govern-
ments. These codes were adopted prior to the development
of solar energy as a feasible energy alternative. Local
36
municipalities are allowed to modify these codes. Thus,
V-ll
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building codes still vary between localities, and the
adoption of a national or state model usually does not
prevent a municipality from making modifications to meet
what are perceived to be local needs.
At the present time, the model codes, federal standards, and
statewide minimum codes do not insure that solar energy
systems will not encounter impediments such as unnecessary
and expensive design and testing requirements. However,
efforts in certain communities to develop a building code
that stresses energy conservation and the use of solar
energy have met with success. Davis, California, recently
adopted a building code that sets certain thermal perfor-
mance guidelines that must be met in any new structure.
Incentives for the use of solar energy are created by
allowing solar heat contributions to be excluded in cal-
37
culating the building's thermal demands. Seattle, Wash-
ington has proposed changes to its building code which
3 8
provide for energy conservation standards in new buildings.
As in the Davis, California, ordinance, ceilings are placed
on thermal energy consumption for buildings, and solar
energy contributions are excluded from calculating the
amount of thermal energy used by the building.
One possible approach to the problems created by variations
in building codes is to have a state agency examine state
V-12
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and local building codes within its jurisdiction and identify
any provisions which may be impediments to solar energy use.
Another approach would have the state develop model regu-
lations for structures in which it is cost effective to
utilize solar energy systems.
Zoning
Zoning is the preeminent device for the public ordering of
land uses. Nearly all communities have adopted some form of
zoning, with the broad purpose of promoting the health,
safety, and general welfare of the community.
The state delegates zoning authority to local governments.
Zoning codes legislatively divide the community into areas
in which only certain designated land uses are permitted.
The general intent is to allow a community to develop in an
orderly manner and in accordance with a comprehensive plan.
Zoning can control height, density, location of structures
on the lot, the particular use to be made of the property,
building styles, materials, and other esthetic considerations.
Zoning may either impede solar development or encourage it.
Impediments may be in the form of use limitations, which are
limitations on how land may be utilized, or may be physical
limitations, such as building height or architectural style.
V-13
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Almost all zoning codes have setback and sideyard require-
ments, some of which may interfere with the optimal place-
ment of solar collectors. Height limitations may prevent a
solar rooftop collector from being placed on a structure
that has already been built to the maximum height allowed in
the zone, and esthetic restrictions may prevent an inno-
vatively designed solar building from being built in an area
of traditionally styled buildings.
In contrast, a community could amend its zoning ordinances
to offer protection for solar users. Solar districts could
be created to ensure unobstructed access to sunlight. The
power to create such districts is analogous to the power of
39
local governments to regulate historic districts. The
community would be divided into districts where various
levels of solar energy use would be protected. Limitations
on height would protect both existing and future solar
collectors. Through such solar districting and height
limitations the risk of losing access to lateral sunlight
would be minimized, thereby removing a major impediment to
solar energy use.
Zoning and Eminent Domain
Care must be taken in drafting a zoning ordinance that
protects access to sunlight because in certain instances the
V-14
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resulting reduction in the property rights of adjacent
landowners may be so great as to constitute a taking. For
example, in a high density downtown area of a large city, a
landowner would expect to use his valuable airspace. If the
zoning ordinance restricted use of a landowner's airspace in
order to protect a neighbor's use of solar energy this could
constitute a taking of a valuable property interest that
40
would require compensation. The boundary between what is
a proper use of the police power in zoning and what is a
compensable taking is one that is constantly undergoing
judicial reexamination.
A municipality may actually prefer in certain cases to
obtain rights to develop airspace by eminent domain rather
than through the zoning power. By using the eminent domain
power and compensating a landowner for the loss of use of
his airspace the municipality will prevent financial hard-
ship for the landowner who has his land use restricted.
In order for a municipality to exercise the right of eminent
domain, the private property must be taken for public purposes
The issue of whether or not a proposed acquisition is really
for a public use or purpose is usually a judicial determi-
nation. There are two views as to what constitutes a
public use. Under the narrow view the public must be
V-15
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entitled, as of right, to use or enjoy the property taken.
It is doubtful whether using eminent domain for protecting
private access to lateral sunlight would be a proper public
purpose under the narrow view, since the direct benefit
would only be for a single individual or a small group. The
broader view of public purpose includes anything that yields
a public advantage. The community need not benefit directly
from eminent domain under the broader view, so long as some
42
benefit mnures to the community.
Case law in Washington, Oregon, and Idaho does not appear to
adopt the broader view as to what constitutes a public
purpose. A "public purpose" in the Pacific Northwest states
seems to require a direct relationship between the public
and the condemned property.^ Because the airspace taken by
the municipality would be for the private use of individual
solar energy users, the courts may perceive the purpose not
to be public, in which case the municipality's exercise of
eminent domain would be considered an unconstitutional
taking. One possible method to encourage the courts to
adopt a broader view of public purpose is to enact specific
enabling legislation.
Although the direct effect of using eminent domain to obtain
airspace would benefit only a few individuals, the overall
V-16
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community would benefit from reduced air pollution, con-
served finite energy resources, and reduced reliance on
limited land and water resources now used for conventional
energy facilities. However, present case law in Washington,
Oregon, and Idaho does not appear to comport with this
broader view. Until such time as the judiciary views the
acquisition of solar airspace easements as a public purpose
or use, the eminent domain power will be of limited useful-
ness to solar energy users.
Transferable Development Rights
Transferable development rights offer a greater degree of
flexibility for solar district planning than does eminent
44
domain. The transferable development rights concept
divides ownership of property into two categories 	 the
land itself and the land's potential for development.
Severance may be possible under proper circumstances, so
that the development potential of a site where continued low
density is desired may be transfered to a site where greater
density is permissible. Under this concept, solar districts
could be maintained in designated low density areas of a
city, and the economic loss due to restrictions in these
areas could be mitigated by transfering development rights
to other areas. The restricted owner would receive the
V-17
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dollar equivalent of his development potential by soiling
his development rights to property owners in higher density
districts unsuitable for solar development. Unlike eminent
domain, the use of public funds is eliminated by permitting
the sale of transferable development rights in the private
marketplace.
The concept of transferable development rights has not been
embraced in many jurisdictions at the present time, including
the Pacific Northwest states. It has, however, been utilized
45
in some historic landmark preservation cases.
Developments in Zoning Law
Currently no municipalities in the Pacific Northwest states
have amended their zoning ordinances to include protection
46
for solar energy use. Certain communities such as Ashland,
Oregon and Soap Lake, Washington, have indicated that solar
47
provisions are being seriously considered. The present
zoning ordinance of Seattle, Washington utilizes standard
height limitations and sideyard setbacks that could offer
some protection to solar access for a homeowner utilizing
solar energy collectors. Similar limitations, as discussed
below, are found generally within the zoning codes of most
4 ft
municipalities.
V-18
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Height and setback requirements may prevent new structures
from being built where they will cast shadows on solar
energy collectors. But in areas of a community in which
buildings are not all uniformly near the zoning height
limitation, or in areas where building lots are narrow,
existing zoning codes will provide substantially less
protection for solar energy users. In addition, neighboring
trees as they grow taller may cast shadows on solar collectors,
and usually cannot be removed under present zoning ordinances.
A substantial threat to use of solar collectors occurs in
the variance process. A neighboring land owner may request
a variance to construct a useful structure that would shade
nearby solar collectors. Without a specific ordinance
protecting solar uses, the solar homeowner may be unable to
establish that his use is more valuable than his neighbor's
structure. A specific recognition of solar interests in the
zoning ordinance would add weight to the argument against
such variances.
Zoning ordinances that protect access to light must not be
so inflexible as to prevent other uses of the land. One
proposed method of amending zoning ordinances would de-
49
lineate three types of solar districts in the municipality.
V-19
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In mandatory solar use districts, all new construction and
major alterations of existing structures would require solar
energy systems whenever economically feasible. In affirm-
ative solar use districts, established in areas where con-
ditions are suitable for solar use in some but not all
structures, the municipality would regulate construction and
other development in order to maintain access to the sun for
those structures which will use solar energy. In other
solar use districts, where conditions would not generally be
suitable for solar energy systems, limited protection of sun
rights would be granted to only the few property owners who
may seek to install solar energy systems.
Solar Skyspace Easements
Another means of facilitating the protection of solar users'
access to sunlight would be to authorize the use of a standard
50
format for voluntary privately negotiated solar easements.
The American Bar Foundation has drafted legislation that
defines a "solar skyspace easement" and provides a standard
method for recording the easement.
The draft model legislation defines a solar skyspace ease-
ment as:
The maximum three dimensional space extending from
a collector to the location of the sun: where a
solar energy system is utilized for heating, to
V-20
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all locations of the sun between 9:00 a.m. and 3:00
p.m. Local Apparent Time (LAT) between September 22
and March 22; where a solar energy system is utilized
for cooling to all locations of the sun between 8:00
a.m. and 4:00 p.m. LAT between March 22 and September 22;
and where a solar energy system is used for heating and
cooling or for hot water uses, to all locations of the
sun throughout the year.
Such legislation would offer a method of protecting access
to sunlight from across neighboring property. Solar sky-
space easements could be purchased, granted, or reserved.
Invasion of the solar easement would be a compensable
property right and possibly subject to injunctive relief.
One advantage of solar skyspace easements is that the access
to sunlight would be uniformly and clearly defined. The use
of solar skyspace easements would require only minor modi-
fications in present legal and regulatory systems.
Other Developments
A method of protecting sun rights currently being considered
in some areas is to develop an allocation system that would
parallel the water allocation system now used in many of the
51
Western states. Sunlight would be allocated in the same
V-21
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manner as water, under a doctrine of prior appropriation.
The prior appropriation doctrine requires generally that the
person claiming a right to water give notice of the appro-
priation in compliance with state laws, divert the water
from a natural stream, and apply the water within a reason-
able time to a beneficial use. Under a prior appropriation
system, sunlight would be allocated to only those owners who
can show a serious intent to make beneficial use of solar
energy. However, introduction of the prior appropriation
doctrine into the fields of solar access and land use law
would cause a major change in the current balance of rights
between adjacent landowners. Poorly drafted or overly broad
legislation could severely restrict development of property
adjacent to land on which a solar collector has been put
into operation, or could lead to too rapid development by
landowners who fear the potential of such restrictions and
who therefore race to develop their property to the maximum
extent possible before any of their neighbors install solar
collectors.^
A variation on the prior appropriation system would include
a permit procedure, by which a state or local agency could
oversee the acquisition of solar rights on a case by case
basis under standards set by legislation. The right of
access to sunlight would vest upon issuance of a final
V-22
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permit. The use of preliminary permits or of permits issued
subject to conditions would assure that permit applicants
develop their solar rights in accordance with desired
standards. This approach would require a substantially
larger administrative machinery than a more self-executing
system, but would allow a correspondingly larger scope for
53
the exercise of administrative control.
The Washington State legislature considered allocating
sunlight under the prior appropriation concept, but the
proposal did not pass in the 1977 legislative session. New
Mexico did pass such legislation in 1977, becoming the first
54
state to protect and allocate sunlight in this manner.
Comprehensive Land Use Planning
Through comprehensive land use planning, local land use
controls such as subdivision regulations, building permits,
and zoning ordinances are prevented from conflicting with
overall state planning goals.
Comprehensive land use plans can be used effectively to
encourage widespread use of solar energy. A comprehensive
planning law would describe the type of uses in structures
V-23
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where solar energy should be encouraged and the manner in
which solar rights and acessibility to sunlight would be
protected. The plan would protect areas suitable for solar
energy systems, and all local plans and ordinances concerning
construction would be required to comply with it. The state
would provide assistance and guidance to local governments
in developing and implementing a comprehensive plan either
by direct participation or by developing model guidelines.
In 197 5 Oregon passed a comprehensive land use planning act
55
that included a provision for solar energy. Under the act
city and county planning commissions are encouraged to
consider solar energy potential in regulating buildings and
open spaces. The act stops short of requiring local govern-
ments to adopt solar energy provisions in their ordinances,
but authorizes local governments to do so. At present,
municipal governments in Oregon have not modified their
zoning ordinances to include solar protection, and neither
Washington nor Idaho have such a statewide comprehensive
plan.
Conclusions and Recommendations
In general, present law does not adequately protect access
to sunlight for users of solar energy.
V-24
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Restrictive covenants can be a primary method for protecting
access to sunlight for new real estate developments.
Anticipating a widespread demand for solar energy systems,
land developers can protect access to sunlight by their
choice of conditions and restrictions to be included in the
deeds to their purchasers. However, restrictive covenants
do not usually provide adequate protection for solar energy
users in areas that are already developed.
The current law of easements and nuisance does not provide
significant protection for users of solar energy.
The adoption of a solar skyspace easement law, under which
easements negotiated between private parties can be recorded
in a standard format, should offer improved legal protection
for many solar energy users.
Revising building codes to emphasize energy conservation
could encourage builders to utilize non-depletable energy
sources such as solar energy.
The above recommendations offer increased legal protection
for users of solar energy while minimizing the need for
major modifications of the present legal system. However,
in order for solar energy use to become increasingly wide-
spread, further modifications may become necessary.
V-25
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The efficient and equitable allocation of sunlight may
demand substantial changes in the approach to zoning laws,
e.g., solar use districts or transferable development
rights.
Similarly, comprehensive land use planning offers a method
of encouraging and protecting solar energy use.
Major modifications in the legal system, such as allocation
of sunlight under the prior appropriation doctrine or some
form of permit procedure, must be carefully considered to
determine if the resulting increase in regulation can
effectively solve the problems presented without creating
serious negative effects, such as over restriction of
adjacent property. The rights of users of solar energy and
of non-users will have to be carefully balanced so that both
receive equitable treatment while protecting the public
welfare generally.
V-26
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References
1.	See U.S. v Causby, 66 S.Ct. 1062, 328 U.S. 256, 90
L.Ed. 1206 (1946).
2.	In Bury v Pope, 1 Cro. Eliz. 118, 78 Eng. Rep. 375
(1586), the court denied relief to a homeowner whose
long term reliance for interior light from sunlight
originating from across his neighbor's land was inter-
rupted when his neighbor built a new house close to the
property line. The court said that the first homeowner
had been foolish to build his house so close to the
property line that his neighbor could build a structure
which shaded it.
3.	See Powell, On Real Property, (Abridged) 11405 (1968
ed.), herein cited as Powell.
4.	See Powell, If405
5.	See Powell, 1(410, 413.
6.	See Powell, 1(413.
7.	In England, the term of years necessary to establish
this protection varied from 20 years to the present day
requirement of 27 years, established in the Right to
Light Act of 1959, 7 and 8 Elizabeth 2, Chapter 56.
8.	The right assures that a reasonable amount of light
flowing through a window would not be interrupted by a
neighbor's structure.
9.	See Parker v Foote, 19 Wendell 309 (N.Y. 1838) for a
case in which an American court rejected the Ancient
Lights Doctrine.
10.	Fountainbleau Hotel Corp. v Forty-Five Twenty-Five,
Inc., 114 So.2d. 357 (Fla. App. 1959).
11.	It is doubtful whether American acceptance of the
Doctrine of Ancient Lights could be helpful to the
solar energy user anyway, because the amount of light
necessary for interior lighting would not normally be
sufficient to operate solar energy collectors. Further-
more, the term of years necessary to establish this
prescriptive easement would presumably begin with the
installation of the solar energy collectors. A neighbor
could thus block lateral light at any time before
installation as well as at any time before the end of
the term needed to establish the easement.
V-27
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12. Powell, 11410.
13.	For examples, see Rose v Denn, 213 P.2d. 810, 188 Or.
1 (1950); Close v Rensick, 501 P.2d. 1383, 95 Id. 72
(1972); Hellberg V Coffin Sheep Co., 404 P.2d. 770, 66
Wash. 2d. 664 (1965).
14.	These two factors would seemingly not coincide often
enough to significantly protect solar energy users.
15.	Powell, 11405, et seq.
16.	Powell, 11670, et seq.
17.	Powell, 1(680-82 .
18.	A solar user may also try to argue that circumstances
have changed since the covenant was originally made.
Historically, the courts have applied this theory only
when drastic changes in the neighborhood have occurred.
Furthermore, the expense of litigating this issue would
deter most homeowners. See Powell, 116 84.
19.	A number of real estate developers were contacted.
Their restrictive covenants were examined and the
overall language appeared to be neutral towards solar
energy.
20.	See Park v Stolzheise, 167 P.2d. 412, 24 Wn. 2d. 781
(1946). For further case support and information, see
58 Am. Jur. 2d., Nuisance, §20.
21.	See 58 Am. Jur. 2d. Nuisance, §9.
22.	See Aldridge v Saxey, 409 P.2d 184, 242 Or. 238 (1965).
23.	See Mathewson v Primeau, 395 P.2d. 183, 64 Wash. 2d.
929 (19 64); also, see 58 Am. Jur. 2d., Nuisance, §44.
Solar energy collectors do not give off any dirt,
noise, dust, odor, etc. that would fall within the
usual examples of nuisance.
24.	See 58 Am. Jur. 2d., Nuisance, §7-8.
25.	In 197 5, the Colorado Springs City Council considered
amending its zoning code to include a declaration that
trees shading solar collectors are public nuisances.
The attempt was abandoned because of the difficulty of
showing that trees were a public nuisance. For further
information, see John Phillips, Assessment of a Single
Family Residence Solar Heating System In A Suburban Setting,
NFS Grant No. GI-4 4210, City of Colorado Springs,
Colorado, (1976).
V-28
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26.	For a different analysis of the potential for protecting
access to solar energy through use of public nuisance
theory, see Goble, "Solar Rights: Guaranteeing a Place
in the Sun," 57 Oregon Law Review 94 (1977).
27.	For more information, see Rivkin, "Courting Change:
Using Litigation to Reform Local Building Codes," 26
Rutgers Law Review, 773, (1973); herein cited as
Rivkin.
28.	See report by the American Bar Foundation, Proceedings
of the Workshop on Solar Energy and the Law (Interim
Report), Rann Serial No. NSF-RA-S75-004, Chicago,
Illinois (1975), p. 2-4; herein cited as the American
Bar Foundation Report.
29.	In 1968, the National Commission on Urban Problems (the
Douglas Commission), conducted a survey and found
building regulations in more than 4,500 jurisdictions.
Eighty percent of the municipalities with populations
over 5,000 had building codes, and nearly one-half of
the 3,000 largest cities had developed their own codes.
Many communities use statewide building codes, but
local governments are generally allowed to modify the
codes to their own needs. Building the American City,
H.R. Doc. 34, 91st Congress^ 1st Session 266 (1968).
30.	Rivkin, p. 781.
31.	Rivkiri, p. 780.
32.	Note, "Building Codes: Reducing Diversity and Facili-
tating the Amending Process," 5 Harvard Journal of
Leg., p. 25, (1968).
33.	Rivkin, p. 776.
34.	See Housing and Urban Development (HUD), Model Code
in New Building Construction (Preliminary Draft),
Washington, D.C., (1977).
35.	R.C.W. 19.27 adopts various model codes as the statewide
building code, such as the Uniform Building Code (197 3
ed.), the Uniform Mechanical Code (1973 ed.), the
Uniform Fire Code (1973 ed.) and the Uniform Plumbing
Code (1973 ed.). Local governments can modify these
codes as long as the modifications do not fall below
the model code's performance standards.
V-29
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ORS §456.730, et seq., authorizes the state to establish
a state building code. Local governments may not make
modifications that conflict with the standards within
the state code.
Idaho Code Chapter 159 (S.B. 1318, 1977) amended the
Uniform Building Code Advisory Act (Section 39-4101, et
seq.) to make the state code optional for county and
city governments.
36.	Ibid
37.	See Ordinance 784 and 787 (1975) , and Resolution No.
1833 (1975) of the City of Davis, California.
38.	Preliminary Draft of City Building Code (1977) presented
by the Seattle Building Code Department, Seattle,
Washington.
39.	The regulation and protection of historical districts
is achieving a growing recognition in many jurisdictions.
See 82 Am. Jur. 2d., Zoning §40.
For example, a federal court has held that a New
Orleans Ordinance regulating the preservation and
maintenance of buildings in the historic French Quarter
is a valid zoning provision and does not violate any
constitutionally protected rights. Maher v. New Orleans
516 F.2d 1051 (1975).
40.	"When a restriction upon the use of property causes it
to depreciate in value...(and) is intentionally placed
upon certain land for the benefit of a specific public
improvement, the courts are still more ready to require
compensation." See Sackman, Nichols, the Law of Eminent
Domain (Rev. 3rd ed., 1976), Section 1.42(9); herein
cited as Nichols.
41.	Nichols, §7.1.
42.	See Nichols, §7.2(1) and (2); Berman v Parker, 348 U.S.
26 (1954); National Solar Heating and Cooling Information
Center, A Forum On Solar Access, Testimony of Mr.
Kenneth Rubin, pp. 54-56 (1977).
43.	For example, case law has required that the public's
use and occupation be direct. The fact that the
public will share in the benefits of private owners is
not usually sufficient. See Umatilla v Richmond, 321
P.2d 338, 212 Or. 596 (1958); Hogue v Port of Seattle,
341 P.2d 171, 54 Wash. 2d. 799 (1959).
V-30
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44.	Transferable development rights (TDR) have not been
recognized yet in most jurisdictions. TDR's are con-
ceptually appealing, and they are proving useful to
certain historical preservation areas. See the American
Bar Foundation Report, "Proceedings of the Workshop on
Solar Energy and the Law" pp. 19-21.
45.	See Brenneman, "Techniques for Controlling the Sur-
roundings of Historic Sites," 36 Law and Constitutional
Problems, (1971); National Solar Heating and Cooling
Information Center, A Forum on Solar Access, Testimony
of Mr. Kenneth Rubin"i pp. 47-49 (1977) .
46.	This is based on conversations with the State Energy
Offices in Washington, Oregon, and Idaho in July, 1977.
47.	Conversations with the City Zoning and Planning Committee
of Ashland, Oregon and Soap Lake, Washington, during
June and July, 1977.
48.	Generally, the height limitation for areas zoned for
single family dwellings is two stories or thirty-five
feet. Sideyard restrictions vary from five to fifteen
feet.
49.	Center for Science in Public Interest, "Solar Energy:
One Way to Citizen Control" pp. 112-114 (1976).
50.	See American Bar Foundation, "Solar Energy and the Law:
The Legal Framework Required to Encourage Greater
Utilization of Solar Energy Systems" §240.10(a)
(1975).
51.	For a general discussion of possible models to follow
in developing solar rights legislation, see Goble,
"Solar Rights: Guaranteeing a Place in the Sun," 57
Oregon Law Review 94 at 130-134 (1977).
52.	National Solar Heating and Cooling Information Center,
A Forum On Solar Access, pp. 24-25, 30 and 34-35
(1977).
53.	For a discussion of proposed legislation, see National
Solar Heating and Cooling Information Center, A Forum
On Solar Access, Testimony of Mr. Gerald Mara, pp. 29-
30 (1977).
54.	The New Mexico legislation is Chapter 169 Laws of 1977.
55.	Or. Rev. Stat. §§215.055, 215.110, 227.230.
V-31
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CHAPTER VI
ENVIRONMENTAL CONSIDERATIONS
Prepared by
Carolyn B. Wilson
Gene Mesher
Rob Wilson
U. S. Environmental Protection Agency
Region X
Seattle, Washington
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Introduction
This chapter examines the principal air, water, solid waste,
and health and safety impacts of solar development for residen-
tial heating in the Pacific Northwest. The interested reader
may find additional details in references cited at the conclu-
sion of this chapter. Because of numerous uncertainties in the
future development of solar energy, the quantitative assessments
presented in this chapter should be viewed as illustrative
examples rather than predictions of what will occur during the
next few years.' Although changes in market incentives and/or
technological developments could alter the quantitative basis
of this analysis, this seems unlikely to seriously affect the
general conclusion.
Potential environmental impacts of residential solar space
heating and hot water heating systems in the Pacific Northwest
depend on the types of solar systems employed, the number of
systems, and the conventional energy systems they displace. In
view of the rapidly-evolving state of solar technology, no
attempt is made in this chapter to characterize a specific
system design type as representative of the configurations of
the future. Instead, during discussion of the potential air,
water and other impacts, the characteristics of various system
types which might result in some impacts are identified.
VI-1
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Quantitative Analysis of Fuel Use and Air Emissions
The major air impacts of residential solar energy use for space
and water heating in the Pacific Northwest and the total energy
savings in the year 1990 were estimated from existing and future
3 4
housing information supplied by the Department of Energy, '
using a method described elsewhere.1
Because heating requirements and insolation rates in the
Pacific Northwest vary significantly depending on whether a
site is east or west of the Cascade Range, two subregions were
considered: western Oregon and Washington, and eastern Oregon
and Washington plus Idaho. Housing stock was assumed to be
distributed according to population: i.e., 88% of Oregon's
housing stock and 75% of Washington's are west of the Cascades.
Annual heating requirements west of the Cascades were repre-
2
sented by those of Portland (4600 degree-days ); east of the
Cascades 6000 degree days (30% more than for Portland) was
assumed. Annual water heating demand was assumed to vary
between single-family homes and apartments but to be indepen-
dent of climate, and unchanged between now and 1990.^
NUMBER OF SOLAR SYSTEMS INSTALLED
The annual construction rate, annual loss rate, number of
housing units in 1977 and 1990 and the assumed solar installa-
4
tion rate determined the number of solar installations m
VI-2
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1990. For single-family homes, 10% were projected as having
solar space heating installed, and 12% as having solar hot
water systems. Financial factors were assumed to limit solar
installations in multi-family units to large apartment complexes
4
with owner-paid utilities. Thus, the rate of solar system
installation for all new multi-family housing was assumed to be
5% for space heating and 6% for water heating applications.
Some solar systems will be installed (retrofitted) in housing
existing in 1977. For solar heating systems and hot water
systems, the assumed retrofit rates are: 200/year from 1980 to
1990 in both Washington and Oregon, and 150/year in Idaho.
Between 1977 and 1980, a total of 500 retrofits of each kind in
the three states was projected. Because of the small number of
projected solar retrofits (only 6% of the total number of
systems forecasted), retrofitted solar heating systems were not
distinguished from systems installed in new housing for the
purposes of this analysis.
Table VI-1 shows the total number of solar energy heating
systems projected to be installed by 1990.
ENERGY SAVINGS FROM SOLAR SYSTEMS
The energy displaced by a building's solar energy system was
estimated for two kinds of solar heating systems (space and
water), in two climatic subregions (east and west of the
VI-3
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TABLE VI-I
Solar Heating Systems Projected for 1990
Space Heating
Water Heating
West of Cascades
Single-Family
Multi-Family
37,000
31,000
43,000
38,000
East of Cascades
S ingle-Family
Multi-Family
16,000
15,000
20,000
17,000
Total
99,000
118,000
Cascades), and for two types of housing units (single-family
and multi-family units). For each case, the energy displaced
per housing unit by a solar energy system was computed by mul-
tiplying the annual energy demand by the fraction of that demand
supplied by the solar energy system.* The average residential
solar space heating system in the Pacific Northwest was esti-
mated to supply 50% of the dwelling unit's annual energy demand
5
and the average solar water heating system, 70%.
The end use demand for space heating for each of the four
housing categories was determined from the energy content and
conversion efficiencies** of the fuels used.
* The calculation procedure is described in Ref. 1, p. 62.
** Assumed conversion efficiencies in residential housing were
40%, 47% and 95% for oil, gas, and electricity, respectively.
These are from Reference 3 which was based on "Residential
Conservation Choices", Portland Energy Conservation Project,
June 1977, prepared by Skidmore, Owings and Merrill.
VI-4
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The hot water energy requirements were estimated by multiplying the
required volume of hot water by the difference between domestic and
supply water temperatures and by the specific heat of water. As-
sumed hot water requirements were 60 gal/day for a single-family
home and 40 gal/day for an apartment, with sufficient heat supplied
to raise the water temperature from 55°F to 140°F.
Total regional energy provided by residential solar heating systems
in 1990 (Table VI-2) was estimated by multiplying the energy
TABLE VI-2
Annual Energy Demand Displaced By Solar Systems Existing in 1990
A. SOLAR SPACE HEATING SYSTEMS
Annual Energy Total Annual
Savings Per Unit Number of Units Energy Savings*
(MBtu's)	(MBtu's)
West of Cascades




Single-Family 24
Multi-Family 9
East of Cascades
X
X
37,000
31,000
=
890,000
280,000
1,170,600
Single-Family 31
Multi-Family 12
X
X
16,000
15,000
=
500,000
180,000
5SM00
B.
SOLAR
HOT WATER
SYSTEMS

Pacific Northwest




Single-Family 10
Multi-Family 7
X
X
63,000
55,000
s
630,000
390,000
1,026,000
* These values are the actual heating requirements and do not
consider the efficiency of combustion of the fuels displaced
by the solar system.
VI-5
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provided by the sun for each building by the projected number
of systems. Residential solar space and water heating systems
are estimated to supply about 2.9 x 10^ million Btu's/year in
1990, thereby displacing an equivalent amount of conventional
energy supplies.
QUANTITIES OF FUEL DISPLACED BY SOLAR ENERGY SYSTEMS
The projected fuel mix for 1990 (from reference 3) is given in
Table VI-3. Only the implications for the most common fuels,
electricity, natural gas and oil, are discussed in this chapter
because these constitute the vast majority of the conventional
heating systems. For purposes of this chapter, solar systems
were assumed to displace these fuels in the same proportion as
they were projected to be installed in new construction.
TABLE VI-3
Projected Residential Fuel Mix
for New Construction - 1977 through 1990'
Space Heating
Water
Oil	Gas	Electricity
Single-Family	5%	20%	75%
Multi-Family	0%	5%	95%
Single-Family	0%	9%	91%
Multi-Family	0%	2%	98%
VI-6
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Multiplying the number of housing units heated with each type of
auxiliary fuel by the corresponding consumption rates (Table VI-4)
TABLE VI-4
Fuel Displaced Annually (Per Housing Unit)
By A Typical Solar Heating System
A. SPACE HEATING Electricity	Natural Gas	Oil
(KWH)	(therms)	(gallons)
West of Cascades
Single-Family 7,300	460	430
Multi-Family 2,900	160	170
East of Cascades
Single-Family	9,600	600	560
Multi-Family	3,770	210	220
B. WATER HEATING
Single Family	3,500	150	130
Multi-Family	2,400	110	90
gives the amount of fuel displaced by solar development. The
total amount of each fuel displaced was calculated as:
Oil
1,300,000 gallons
= 1.8
X
1011
Gas
7,900,000 therms*
= 7.9
X
1011
Electr ici ty
710,000,000 KWH
= 7.6
X
1012
* one therm = 100 ft of natural gas
** assuming coal-fired electric power generation (33%
conversion efficiency ).
VI-7
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EMISSIONS DISPLACED
Where a solar space or water heating system is used with a
natural gas or oil-fueled auliliary heating system (or wood,
coal, or propane, for that matter), the solar heating system
will substitute for some onsite fuel combustion and its
by-product pollutants. The displaced emissions are those pol-
lutants which would have been emitted if a conventional backup
heating system had been used instead of the solar system. The
amount of pollutant emissions displaced equals the volume of
displaced fuel multiplied by the emission factor for that type
of fuel. The emission factors for natural gas and residential
fuel oil combustion are shown in Table VI-5.
TABLE VI-5
6 7
Emission Factors for Common Residential Fuels '
Fuel TSP SO	NO	HC	CO	Units
x	x
Distillate Oil 2.5 72 *	18	1	5	lb/103 gal
Natural Gas 10** 0.6	80	8	20	lb/106 ft3
7
Note: * For 0.5 percent sulfur content
TSP - total suspended particulates
SO^ - sulfur oxides
NO^ - nitrogen oxides
HC - hydrocarbons
CO - carbon monoxide
6 3
** Range is given as 5 to 15 lb/10 ft in Reference 6
Most of the energy displaced by solar systems is electrical and
so will not have environmental consequences due to onsite air
VI-8
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emissions. Emission factors for oil and gas consumption (Table
VI-5) multiplied by the total displaced volumes for these fuels
give the total onsite emissions displaced (0.5% sulfur content
7
for northwest distillate heating oil was assumed ). Tnblo
VI-6 lists total displaced onsite emissions in the Pacific
Northwest.
TABLE VI-6
Total Onsite Air Emissions Displaced by	Solar Heating Systems
in the Pacific Northwest	- 1990
(lbs/year)
TSP SOx N0x	HC CO
Oil 3,200 94,000 23,000	1,300 6,500
Natural Gas 7,900 500 63,000	6,300 16,000
Although electricity has few environmental effects at the point
of use, it does have important environmental effects at the
generation site. Because the hydroelectric potential of the
8
Pacific Northwest has been extensively developed ' additional
demand will have to be met by thermal generation (either coal
or nuclear). Solar energy systems installed in new housing
will then be displacing electricity which would be generated
thermally. Therefore, to evaluate the environmental consequen-
ces of solar energy systems which have electric heat for backup,
the environmental impacts of thermal power generation must be
VI-9
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examined.*
The majority of the gases emitted from conventional coal-firtni
power plants will be combustion by-products of coal burning.
There are few air emissions normally released from nuclear
power plants. For purposes of this chapter, we will assume
that residential solar heating will only displace coal-fired
generation.** Coal-fired electrical generation, because of
clean air requirements, will control the large quantities of
particulates and sulfur compounds otherwise emitted. Thus, the
gaseous emissions displaced will be much smaller than in the
uncontrolled case. The assumed emission factors for controlled
emissions from burning Western coal are tabulated in Table VI-7.
The electrical energy displaced by solar systems in 1990 would
be equivalent to that from combustion of 7,600,000 MBtu's of
* Many other indirect impacts are recognized as relevant to
evaluation of solar and conventional energy sources (e.g.,
extraction of minerals such as Al, Pe, Cu, and fuels -
petroleum, coal, uranium; transportation of materials, pro-
ducts, and wastes; refining and manufacture; disposition of
waste products; and energy use for each activity). However,
a quantitative analysis of such impacts is beyond the scope
of this chapter.
** Note that Puget Power and PGE are building five coal plants
in Oregon and Montana. PGE, Puget Power and WPPSS are
planning/building nuclear plants. However, for 1990,
nuclear generating capacity is projected to greatly exceed
coal generating capacity. Thus, to the extent that solar
units replace base loads, they would replace base load
nuclear power. Similarly, to the extent that electrical
back-up systems operate in a mode that increases electrical
demand during normal peak demand periods, they could
increase utilization of fossil-fired (and hydro) peaking
capability. (See Chapter IV).
VI-10
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TABLE VI-7
Emission Factors* for Coal-Fired Power Plant - 1990
NO
SO
x
TSP
X
2	lbs/MBtu* s
03	lbs/MBtu's
6 lbs/MBtu's
coal (assuming an efficiency of 1/3 for the power plant). Thus,
the displaced offsite emissions for that year would be:
Due to the small number of residential solar systems installed
compared to total electrical energy demand, these displaced
total emissions would amount to only 22% of the controlled
emissions from a 500 MW coal-fired power plant.** A greater
number of solar systems installed would result in a greater
relative decrease in air emissions.
HEAT REJECTION
Thermal discharges are roughly equivalent for both coal-fired
and nuclear power generation, since the conversion efficiency
Q
* Based upon EPA draft proposed regulations for new sources
** at a 75% capacity factor
NO
SOx
TSP
x
1,510,000 lbs
227,000 lbs
4,540,000 lbs
VI-11
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is about the same, roughly 1/3, in both cases.* Therefore, for
every kilowatt-hour generated, two kilowatt-hours of thermal
energy are rejected to the environment as waste heat. However,
even widespread use of solar energy seems unlikely to effect a
significant change in water quality impacts from heated
discharges of coal or nuclear power plants, because the energy
from all of the solar energy systems projected to be in place
by 1990 will be small compared to the output of a typical
baseload power plant.
Outgassing
Onsite air emissions are created by some solar heating systems
due to outgassing** of solar collector materials. Some insu-
lating materials, many of which are composed of complex organic
materials, will, when heated above certain temperatures, release
volatile compounds. The compounds are released either because
chemical compounds in the insulation materials degrade thermally
above certain temperatures into volatile compounds, or because
volatile compounds trapped in the insulation material during
the fabrication process rediffuse out due to the effects of
high temperature during the operation of the solar system."^
* Actual efficiencies are somewhat less for nuclear than for
coal power generation.
** Outgassing is the release of gases, usually at elevated
temperatures, from solid materials.
VI-12
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These processes could occur under stagnation conditions** in
which the solar collector is experiencing a solar heat gain but
other conditions make the operation of the solar heating system
undesirable. Hence, no working fluid is flowing across the
collector surface to remove the absorbed energy, and tempera-
tures increase to much higher than those of normal operation.
The impacts of outgassing depend on whether the gases are
released and inhaled (health impact) or simply deposit a coat-
ing on the glazing surface, lowering the transmissivity of the
glazing material and impairing collector efficiency (system
impact). However, the quantities emitted are so small that
there can only be a potentially significant health impact if
the gases are released in a relatively confined space, as
discussed later in this chapter.
Disposal of Heat Transfer Fluids
The deficiencies of water as a working fluid can be minimized
by dissolving certain compounds in it. In areas where a solar
heating system using water as the working fluid is not drained
in winter, but the climate is cold enough to warrant it,
anti-freeze may be added to depress the freezing point of the
working fluid. Since the water may eventually begin to corrode
** Stagnation conditions occur when there is no flow of heat
transfer fluid across the absorbing surface of the solar
collector. To reduce outgassing, the stagnation temperature
should not exceed the upper temperature limit of the selected
insulation material.
VI-13
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some system components, corrosion inhibitors are sometimes
added. Bactericides may be added to prevent slime formation.
The actual compounds involved and their toxicities are dis-
cussed in the Health and Safety section of this chapter.
Periodically, this working fluid solution must be flushed and
may become a source of water pollution. Precautions are neces-
sary to prevent discharge of solar system working fluids into
water systems in which the additives could have harmful
effects. In this regard, the U.S. Department of Housing and
Urban Development's supplement on Intermediate Minimum Property
Standards for Solar Heating and Domestic Hot Water Systems^,
which sets guidelines for the disposal of toxic heat transfer
fluids, should be referred to (section S-615-9). For systems
not using merely air or potable water as heat transfer fluids,
the standards require that a catch basin be provided to contain
the heat transfer fluids prior to dilution to lower toxicity
levels and/or discharge into the sanitary sewer system (not the
storm sewer system)."^
Solid Waste
Solar energy systems will both displace solid waste impacts
that would otherwise result from substitute energy sources and
create new impacts. The displaced impacts include land dis-
turbances related to fuel extraction (e.g. coal and uranium
VI-14
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mining) and solid waste residuals from power generation (e.g.
collected flyash and nuclear wastes). Impacts created by solar
energy development include land disturbances due to mining and
solid wastes from processing of the component materials (e.g.,
aluminum, copper, glass, steel) as well as from disposal or
salvage of systems. It should be noted that the impacts
created by solar systems could be minimized by recycling the
materials into new solar systems or other products.
Where solar installations displace energy that would have been
delivered by thermal power plants, they may reduce potential
solid waste impacts associated with coal or uranium. Coal use
involves disposal of both the mining overburden and the large
quantities of coal ash produced in combustion (ash content of
coal is typically about 10% of the coal weight). Uranium
mining and milling is a major source of solid wastes and radio-
active tailings have posed some serious health problems.
Further, the spent fuel rods or reprocessing wastes from nuclear
reactors are another source of solid waste. Although smaller
in quantity than other solid waste sources, no satisfactory
long-term disposal method for radioactive wastes has been
decided upon. However, the Administration has announced that
it intends to decide upon a national nuclear waste management
policy by the end of 1978.
Solid wastes also may be created by the disposal of solar
systems. The amount of solid wastes created in this way depend
VI-15
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on the recycling potential of the constituent materials. Flat
plate solar energy technology has a high recycle potential
since the existing technologies associated with recycling of
most of the major materials components - aluminum, copper,
steel and glass - are among the best developed. All have
energy-intensive production processes which make recycling
favorable due to the relatively small energy investment which
has to be made when the materials are reprocessed rather than
being produced from ore. In the western U.S., nearly all steel
production is accounted for by reprocessing of scrap steel.
Because of increasing demand for and price of electricity,
aluminum manufacturers are putting a much greater emphasis on
recycling. As high-grade copper ore has become scarce, copper
recycling has become more widely practiced. In 1969, well
before the drastic change in energy prices which accompanied
the 1973 oil embargo, roughly 1/2 of the available aluminum and
12
5/8 of the available copper were already being recycled.
Complex organic materials used in some solar systems components,
such as insulation and plastic glazing materials such as Tedlar,
have a much poorer recycling potential since those materials
are much more difficult to reprocess than to produce from raw
materials (i.e., petroleum).
Health and Safety
With solar heating technology, there are potential impacts on
the health and safety of workers who construct, install and
VI-16
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maintain solar systems and those people who live in close
proximity to solar systems. Pour types of such impacts will be
discussed below. They are: materials toxicity, glass breakage,
noise, and glare.
MATERIALS TOXICITY
Two phenomena, the outgassing of collector insulation materials
and potable water contamination with solar system working
fluids, have potentially important health effects.
Outgassing, as discussed earlier in this chapter, results from
overheating those materials which, at elevated temperatures,
may release gases. Temperatures may be elevated due to stagna-
tion conditions (no circulating heat transfer fluid in liquid
or air collectors) or fire from outside sources.
However, the quantities of gas emitted will be small and a
potential hazard is only likely under certain circumstances.
If the emitted gas is toxic and is confined to a small space
which is inhabited then there is a potential danger from
inhalation. However, this is unlikely except in certain cir-
cumstances such as where the collector is integrated into the
roof structure but poorly sealed from the living quarters, thus
allowing the outgassed gases a pathway to the interior. In
this case, proper sealing of the collector insulation and/or
the roof would eliminate the pathway. In a fire, very toxic
fumes of such gases as cyanide, toluene disocyanate (TDI),
VI-17
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hydrogen chloride, ammonia, nitrogen oxide and others may be
emitted as breakdown products of some of the plastic or synthe-
tic components used in insulation.1^ However, under normal
conditions, the health hazard due to outgassing should be
minimal.
As mentioned under the section on disposal of heat transfer
fluids, potable water contamination is another potential problem
which could also be the result of a faulty design. If a leak
develops in a solar water heating system, then those chemicals
which were added to the water in the solar system as corrosion
inhibitors, freezing point depressants, or bactericides could
enter the potable water system. The toxicity of these differ-
ent compounds is examined in Table VI-8. It should be noted
that the probable pathways for accidental human ingestion imply
considerable dilution of the additives. Even taking this into
consideration, however, some of the diluted compounds could be
highly toxic. Use of such compounds should be avoided if a
very high confidence in the isolation of the working fluid
12
cannot be achieved. One method that has been recommended
to prevent fluid from entering the potable water system from a
leak in the heat transfer coils is use of a double-walled heat
exchanger.* Addition of a non-toxic dye to the heat transfer
A double-walled heat exchanger design should keep a minimum
of two walls or interfaces between the toxic liquid and the
potable water supply.
VI-18
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fluid to provide an indicator of a leak is another recommended
14
precaution. Above all, it should be stressed that working
fluid solutions must be isolated from potable water systems and
aquatic ecosystems.
GLASS BREAKAGE
Some collectors use glass cover plates which, if broken and
deposited in yards or other play areas, may be a potential
hazard to children. Breakage may occur in several ways: e.g.,
thermal cycling, vandalism and hail. For example, the daytime
temperature of the glass may reach roughly 150-200 °F, but
drop at night to ambient temperature (or below).* Under stag-
nation conditions (no flow of heat transfer fluid), this tem-
perature difference can become even greater. Ultimately the
thermal stress on the glass may be great enough to cause
breakage1^ if the glass is not properly mounted to allow for
heat expansion.
Glass breakage by vandals can be a problem as with any glass
structures (windows, for example). Hail damage will probably
not be a serious problem since there are few locations in the
Pacific Northwest which have hail frequently or in large enough
sizes to be potentially damaging.
* Radiative cooling to the clear night sky could reduce surface
temperatures to below ambient air temperatures.
VI-19
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Type of Compound
Corrosion Inhibitors
Chromate Salts
Barate
N1trl te
Nitrate
Sulfite
Sulfate
Arsenate
Triazoles
Benzoate Salts
Silicates
Phosphates, and
Organophosphates
Antl-Freezes
Ethylene Glycol
Propylene Glycol
Dipropylene Glycol
^ Bactericides
m	Chlorine
I	O-phenylphenol
Trlchlorophenols
2,3,4,6-Tetrach1oropheno1
TABLE VI-8
Working Fluid Additives and Their Toxicities1
Use
Typical or Estimated Concentration
in water (ppm unless specif jedj^
protect against corrosion of:
Iron, Z1nc, Copper & Brass
Iron and Iron Alloys
Iron and Aluminum
similar to nitrites
all metals
similar to sulfites
general, best for Aluminum
Cuprous metals
Iron
Copper, Aluminum and Iron
Iron and Aluminum
20 - 30
20 - 30
up to 2000
similar to nitrites
. about 1000
similar to sulfites
50 (Illustrative)'
20 - 30
30
50 (illustrative)
1 - 3
Oral Toxic Dose^ (_for_ a chijd^)
10 l (10.5 gal)= Lofo at 25ppm
171 1 (45 gal)= L0L0 at
.04 1 (1.4oz)= LDi0 at 1500ppm
2.67 1 (.7 gal)= LDLo at 1500ppm
.14 1 (4.7 oz)- TD§o at lOOOppin
not available
12 1 (3.2 gal)- TDLo at 50 ppm(over 3 weeks)
400 1 (106 ga1 )= LOLo at 25ppm
relatively non-toxic
10-100 1 (3-30 gal) = LDlo at 50ppm
6000 1 (1600 gal )= LDLo at lOppm
depresses freezing point
10 - 20% solutions
.15 1 (.04 gal )= LDLo In a 20% solution
2.0 1 (.55 gal )= LD50 in a 201 solution
.5-.1.5 1 (.13 - 40 gal) in a 20* solution
is a probable lethal dose
control microbiological growths
0.3 - 1.0
150 - 200
7 - 20
50 1 (13 gal)= LDLo at 200ppm
500-5000 1(130 - 1300 gal) at 20pr™ is
probable lethal dose
20 - 400
.25-2.5 1 (.07-1.3 gal) at 400ppni is a
probable lethal dose
pentachlorophenol
(fungicide, mollusciclde)
20 (illustrative)
2.9 1 (0.77 gal )= LDLo at 200ppm
-------
(footnotes for table)
Prom Appendix XI of Reference 10, ERDA Solar Program Assessment (Draft).
Oral toxic dose assuming ingestion of solar system working fluid at the given concentration. Further dilution as a
result of leaks into potable hot water systems would imply ingestion of larger quantities.
Toxicity is based on lethal concentration expressed in mg of toxic compound per Kg of body weight, which was then used
to estimate the lethal dosage for a 20 Kg (44 lb) child. Adult dosages will be different due to changes in sensitivity
with weight and age.
LD. (lethal dose low) - the lowest total dose of a substance ingested over any given period of time in one or several
portions which was reported to have caused death in humans or animals.
TDj- (toxic dose low) - the lowest dose of a substance introduced over any given period of time which was reported to
produce any toxic effect in humans or to produce carcinogenic, teratogenic, mutagenic, or neoplastic effects in humans
or animals.
LDcq (lethal dose fifty) - a calculated dose which is expected to cause the death of 50 percent of any experimental
animal population following ingestion of the substance.
Value given was for comparative purposes and is not necessarily a typical or probable concentration.
-------
If glass breakage occurs frequently at a site, a parapet around
the system could prevent broken glass from falling to the ground
and becoming a hazard. Use of heat-tempered glass would alle-
viate the problem (because, when broken, it "beads" into small
16
bits instead of long jagged pieces), as would use of poly-
meric and other non-glass glazing materials which are not as
sensitive to stress.
NOISE AND SOLAR HEATING SYSTEMS
Solar heating systems require small pumps or fans for the
circulation of the working fluid. These do not represent a
noise impact problem. Solar-assisted heat pumps may have
significant noise related impacts. However, we have assumed
that there would be very few such systems installed in the
Pacific Northwest through 1990, implying that their potential
noise impact will not materialize.
GLARE
One possible source of objection to solar energy systems is
that some designs might create an inordinate amount of glare,
resulting in a potentially annoying and hazardous situation.
Glare can be due either to reflection off the glazing or off
the collector framework. In the case of a solar heating system
that has no shading structures to interfere with its perform-
ance, reflected sunlight will be sent back into the atmosphere.
In cases where there are intervening structures, reflections
VI-22
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may be cast on those structures. In such cases, a sun-shield
may have to be constructed to prevent this if the structures
are inhabited. However, reflections from flat plate solar
17
collectors are expected to be of low intensity. Lastly,
glare from sunlight reflected off metallic surfaces of the
collector frame could be alleviated by painting the framework
with a nonreflective paint.
Land Use
Land use considerations vis a vis solar energy development
relate to factors such as: shading of the solar collector by
other structures, the geographic location of the site, system
size and land availability, orientation and sizes of any struc-
tures on the site, planning and development considerations, and
aesthetic implications of the visual characteristics of the
solar system.
Shadows created by a neighboring structure which fall on a
solar collector would obviously decrease the collection effi-
ciency of that system. This legal issue is discussed in
Chapter V. Because shading in late afternoon or early morning
may be tolerated*, removal of all shading structures would not
*Some shading during hot summer months may be tolerated if the
heating demand is significantly reduced during that time.
(This is not likely to be the case for hot water heating
demand.) For example, in some areas, selected deciduous trees
may provide summer shade for passively heated solar buildings
yet avoid serious interference with solar system performance
during most of the principal heating season.
VI-23
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necessarily be demanded.
Because solar collector areas are projected to be on the order
of about 100 square feet for solar water heaters and about
300-600 square feet for solar space heaters for single-family
housing, it is doubtful that the land needed for solar systems
will exceed available roof areas. Walls may also be used for
collection. Reflectors would assist in either case. Thus, no
substantial new land commitments should be necessary to utilize
solar energy for residential space and water heating. However,
collectors installed adjacent to the dwelling may be desirable
for some situations (e.g., some multi-family units of more than
one story). Attention to collector orientation and integration
of the solar system in the planning stage should minimize the
number of new structures where detached collectors are used.
However, the additional land area for a detached collector need
not serve only this purpose. Land beneath an elevated collector
could be used for other purposes.
Solar energy development may affect the visual environment.
Because the optimal orientation for a flat plate solar collector
18
is generally within a few degrees of south, buildings de-
signed to have such solar collectors aligned with conventional
walls or roofs may be oriented accordingly. However, variations
of up to 25° from true south cause relatively small reductions
18
in collector efficiencies. An east-west orientation of the
VI-24
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long axis of solar-heated buildings is also often desirable to
achieve passive solar heat gains in winter through south-facing
windows.
Street and building layouts of housing developments may thus be
affected by an increased demand for heating with solar energy
systems. New housing could be planned to provide wall or roof
areas oriented favorably for solar collectors. Conversely,
real estate planning which fails to consider solar energy con-
straints could hinder the installation of solar heating systems.
Finally, the visual aesthetics of a solar energy system may
serve to enhance or suppress solar energy development at a
given location. For example, if the visual characteristics of
solar heating systems are considered to be inappropriate to an
existing neighborhood housing style, there might be resistance
to the installation of solar systems there on the basis that
the structure does not conform to housing style. However,
carefully designed solar systems could be successfully inte-
grated into building styles in many instances and overcome such
objections. Suggested design considerations for incorporation
19
of solar systems have been discussed.
Air Pollution Effects on Insolation in the Pacific Northwest
Air pollution can reduce the amount of insolation received at a
solar collector surface in several ways. First, the radiation
VI-25
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may be absorbed by the pollutants. Second, the radiation may be
scattered* (although almost all of the radiation which has
undergone primary scattering still reaches the ground). Third,
particulate matter (e.g. dust) may deposit on the solar collector
surface, thereby reducing its efficiency. Finally, pollutants
may serve as condensation nuclei and increase the incidence of
clouds or fog. Since man-caused weather modification is an
extremely difficult situation to evaluate, it is not known
whether this last problem is significant in the Pacific Northwest.
There are many factors which together determine the effect that
air pollutants have on insolation. They include the following:
AEROSOLS
-	Vertical and horizontal distribution
-	Size distribution
-	Shape and orientation
-	Refractive characteristics (real and imaginary parts)
to determine absorption
GASES
-	Vertical and horizontal concentration distribution
-	Conversion rate for gaseous precursors of particles
INSOLATION
-	Wavelength
-	Solar elevation (dependent on latitude, time of day,
time of year)
-	Ground albedo
WEATHER
-	Cloudiness
-	Temperature
-	Pressure
-	Humidity
-	Wind (dispersion, dust storms)
* A direct or focused-beam type of solar collector would be
affected more by pollutants which scatter insolation than a
flat-plate solar collector which collects both direct and
diffuse sunlight.
VI-26
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The number and interdependency of these variables make the problem
of modeling the effect very complex. Uncertainty about any one
variable adds to the uncertainty of the answer that one might
obtain from modeling. Most of the factors concerning aerosols and
gases are not known for even a few locations in the Pacific
Northwest. Therefore, quantifying the effect of air pollution on
insolation in the Pacific Northwest is not possible due to the
lack of information.
However, a qualitative estimate of the effect can be made based on
a comparison of cities in the Pacific Northwest with other cities
for which measurements of urban-rural differences in solar flux
20
have been made. Peterson and Flowers have found that an urban
site in St. Louis received an average of 2-3% less total solar
energy than a nearby non-urban ("non-polluted") location. For Los
Angeles, which probably has the greatest optical depth (greatest
attenuation of solar energy) of any major U.S. city, the decreased
solar energy intensity at ground level averaged 11% less than in
the nearby rural areas. It is reasonable to assume that cities in
the Pacific Northwest would have much less of a problem than Los
Angeles and probably less than St. Louis.
Although on the worst days in the worst areas, insolation may be
reduced by air pollution by as much as 15 or 20%, this would not
be typical. Significant effects are likely to be very localized,
relatively infrequent, and of short duration. On the average in
VI-27
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the Pacific Northwest, the insolation received at the ground is
probably reduced by air pollution by less than 2-3% in the cities
and not even that much in non-urban areas. Thus, the reduction of
insolation received at the ground by air pollution does not seem
to be a significant problem in the Pacfic Northwest.
Conclus ions
The environmental considerations of the projected increase in the
number of residential solar systems for space heating and hot
water by 1990 are as follows:
1. At the postulated level of development and for the projected
fuel mix, the nearly 99,000 residences served by solar space
heating systems and the nearly 118,000 residences served by
solar hot water systems in the Pacific Northwest would annually
replace a total of approximately 1.3 mil- lions gallons of oil,
7.9 million therms of natural gas, and 712 million
kilowatt-hours of electricity.* The annual air emissions that
would have been created by combustion of this oil and gas
comprise approximately 11,000 pounds of total suspended
particulate; 94,000 pounds of sulfur oxides; 86,000 pounds of
* Expressed in terms of a single fuel, this annual energy savings
is equivalent to 51 million gallons of oil or 61 million therms
of gas or 840 million KWH of electricity - enough to heat the
homes of 190,000 people for one year (59,000 residences with
space heating demands similar to those for west of the
Cascades).
VI-28
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nitrogen oxides; 7,600 pounds of hydocarbons; and 22,000 pounds
of carbon monoxide. If the electricity would have been
generated by a coal-fired power plant, the coal combustion
would have created additional annual emissions of approximately
230,000 lbs of total suspended particulate, 1,500,000 lbs of
SO , and 4,500,000 lbs of NO (assuming that emissions
X	X
would be controlled). These emission savings are a relatively
small fraction of the total emissions in the Pacific Northwest.
If the electricity had been generated by a nuclear power plant,
few air emissions would have occurred at the power plant site.
(For either coal or nuclear power production, additional
environmental impacts from fuel production and residuals
management would have occurred away from the power plant site.)
2.	The effects on land use of widespread adoption of residential
solar energy systems may be the most visible environmental
change but are not expected to cause serious adverse impacts.
Proper planning by social institutions and private individuals
for solar installations should consider potential visual
impacts of the systems, possible alterations in street, lot,
and-building layout; and adjacent land uses in relation to the
need for access to sunlight.
3.	Some of the heat transfer fluids may contain toxic materials.
Proper disposal of toxic heat transfer fluids and isolation
from potable water systems is necessary to prevent dangers to
health.
VI-29
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4.	Solid wastes from disposal are not likely to pose problems.
The principal materials of solar systems - aluminum, copper,
glass, and steel - have good potential for recycling, although
other components (plastics, styrofoam insulation) do not.
5.	On the whole, it appears that increased use of solar energy for
residential space heating and hot water would have small,
positive environmental effects. Impacts created during
manufacture of the systems from recycled materials
could be less than from primary materials. In either case, the
operation of the system over its lifetime would displace
effects that would otherwise accrue from operation of
conventional power sources to provide the energy.
6.	The reduction of insolation received at the ground by air
pollution does not seem to be a significant problem in the
Pacific Northwest.
VI-30
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References
1.	U.S. Environmental Protection Agency. {EPA-600/7-76-014)
Potential Environmental Impacts of Solar Heating and
Cooling Systems, October 1976.
2.	FEA/G-76/154, Buying Solar, Federal Energy Administration,
June 1976, p. 24.
3.	Dolan, Terry. Definition of Housing Stock (unpublished
report), Department of Energy, Region X, Seattle,
Washington, November 1977.
4.	Dolan, Terry. Rate of Solar Heating Equipment Installation
Forecast (unpublished report), Department of Energy, Region
X, Seattle, Washington, November 1977.
5.	Dolan, Terry; Department of Energy, Region X, Seattle,
Washington. Written communication to Carolyn Wilson, EPA,
Region X, Seattle, Washington.
6.	AP-42, Compilation of Air Pollutant Emission Factors,
U.S.E.P.A., Office of Air and Waste Management/Office of
Air Quality Planning and Standards,	August 1977, pp. 1.3-2
and 1.4-2.
VI-31
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7. Brown, Prank; Department of Energy, Region X, Seattle,
Washington. Oral communication to Carolyn Wilson, EPA,
Region X, January 6, 1978.
8• Review of Power Planning in the Pacific Northwest-Calendar
Year 1976 by Power Planning Committee of the Pacific
Northwest River Basins Commission, May 1977, p. 22
9.	U.S. Environmental Protection Agency, Draft Proposed
Regulations: 40 CFR Part 60, Standards of Performance for
New Stationary Sources,-Electric Utility Steam Generating
Units, November 29, 1977, (unpublished), pp. 2-4.
10.	ERDA. Environmental Impact Assessment of the National
Solar Heating and Cooling Program (Draft), April 18, 1977.
11.	HUD, Intermediate Minimum Property Standards Supplement for
Solar Heating and Domestic Hot Water Systems, Volume 5,
U.S. Department of Housing and Urban Development,
Washington, D. C. 1977, pp. 6-46.
12.	F. R. Jackson. Recycling and Reclaiming of Municipal Solid
Wastes, Noyes Data Corporation. 1975.
13.	Ibid, pp. 5-42
VI-32
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14.	ERDA, op. cit., p. 87.
15.	ERDA, op. cit., p. 98.
16.	ERDA, op. cit., p. 99.
17.	ERDA 77-47/1, Solar Program Assessment; Environmental
Factors - Solar Heating and Cooling of Buildings, ERDA (new
Department of Engergy), Washington, D.C. March 1977.
18.	Anderson, Bruce. The Solar Home Book, Chesire Books,
Harrisville, N.H., 1976, p. 175.
19.	Szokolay S.V. Solar Energy and Buildings, Halsted Press
Division, John Wiley and Sons, New York, New York, 1975.
20.	Peterson, James T. and Edwin C. Flowers. "Interactions
Between Air Pollution and Solar Radiation," Solar Energy,
Vol. 19, 1977, pp. 23-32.
VI-33
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APPENDIX A
CURRENT SOLAR HEATING AND COOLING
RESEARCH IN THE PACIFIC NORTHWEST
Prepared by
G. L. Liffick
U.S. Department of Energy
Richland, Washington
-------
PROJECT TITLE
SPONSOR
Solar Program
Seattle City Light
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
In-house and contractors
Al Yamagiwa
Seattle City Light
1015 Third Ave.
Seattle, WA 98104
625-3553
FUNDING
PERIOD OF PERFORMANCE
Not available
Continuing
Technical Summary
Seattle City Light's solar program currently consists
of three major projects:
A home called "Project Weathervane," has been constructed
which features a 6 kW windpower generator in addition to solar
energy collectors and a heat pump. The purpose of this pro-
ject is to determine how effective the sun and wind can be in
supplying energy to homes in Seattle. During the nearly two
years of operation, the solar heating system has supplied
4 7% of the energy required for heating the home in the winter
while windpower has supplied less than 10%. The solar system
also provides a large portion of the home's hot water needs.
A technical report on the experimental result of the project
was presented at the 12th Intersociety Energy Conversion and
Engineering Conference, Washington, DC, August 19 77.
A-l
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An experimental solar-panel/heat-pump system has been
delivered to Seattle City Light and will undergo experi-
mental testing to supply hot water at the city's Beacon Hill
Fire Station No. 13. Designed and built in Richland by
Sigma Research Corp., the experimental solar panels have an
overall efficiency of 65% collecting about 85% of the system's
heat from direct solar radiation and about 15% from surround-
ing air. The panels operate slightly below air temperature,
enabling the uncovered panels to collect, rather than lose,
heat in the air. Because of low installation costs and high
efficiency, Sigma's solar heat system is expected to pay
for itself in 1/3 the time of conventional solar heat systems.
If the initial testing of the system proves successful a
scaled-up version will be tested on a home or City facility.
To further research into passive solar heating system
technology, City Light is pursuing a new research effort to
explore the utilization of passive solar heating systems
(requiring low electrical energy consumption) in combination
with super-insulation for energy conservation in residential
heating applications. Five sites have been identified, and
the solar potential for each structure has been analyzed for
its suitability to solar exposure based on surrounding,
terrain, shading and location, etc. If the site identifi-
cation and preliminary site surveys show promise, a second
A-2
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phase will be negotiated with the contractor, ECOTOPE, to
incorporate a specific design or sets of design for con-
sideration on a remodel of a residence or public facility.
If Phase II is successful, future follow-on contracts may
consider development of solar energy handbooks, solar
workshops, educational curriculum for schools, etc.
A-3
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PROJECT TITLE
SPONSOR
Solar Program
Various organizations
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
University of Oregon
Solar Energy Center
Prof. J. Reynolds
Dept. of Architecture
University of Oregon
Eugene, OR 97403
FUNDING
PERIOD OF PERFORMANCE
Total not available
Continuing
Technical Summary
The Pacific Northwest Regional Commission has provided
$67,000 to the University of Oregon. These funds will be
used to study three basic areas of concern for solar energy
development in the Pacific Northwest. The first aspect is
a program to involve community and state colleges in solar
energy collection with flat-plate collectors and in solar
radiation data collection. This program, under the guidance
of the University of Oregon solar group takes advantage of
the experience obtained in the past several years to help
generate enthusiasm and local expertise to further solar
work at the local level. The second aspect of this project
is a continuation of the work on reflector-collector combi-
nations which is already in progress at the University of
Oregon through an experimental program. This study is backed
A-4
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up by further analysis of the ongoing Mathew House in
Coos Bay, Oregon. The third aspect of the project involves
the development of a passive solar energy workbook for the
Northwest for architects, homebuilders, contractors and
owner-builders. A publication on passive solar is planned
for early 1978.
The University of Oregon has designed and built the
Noti greenhouse 25 miles northwest of Eugene, OR. This
greenhouse has operated successfully through its first
winter with the sun as its only heating source. A report
on the Noti greenhouse is available for $2.00 (No. CFR 121)
from:
The Center for Environmental Research
School of Architecture and Allied Arts
University of Oregon
Eugene, OR 97403
A-5
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PROJECT TITLE
SPONSOR
Solar Hot Water Heater
Oregon State Community
Services Program
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Eastern Oregon Community
Development Council
Rich Huggins
Eastern Oregon Cummunity
Development Council
P.O. Box 1006
LaGrande, OR 97850
FUNDING
PERIOD OF PERFORMANCE
Approximately $12,000
1976-1977
Technical Summary
An inexpensive solar hot water heater system has been
developed which is suitable for low income families. The
system incorporates freeze protection and is designed to
act as a preheater for an existing hot water tank. All
materials for the system are available from local hardware
and builder supply stores, and the system can be assembled
with hand tools. A booklet titled "Solar Hot Water Heater"
which describes the system is available from:
National Center for Appropriate Technology
P.O. Box 3838
Butte, MN 59701
A-6
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PROJECT TITLE
SPONSOR
Solar Greenhouse
Feasibility
U.S. Community Servicos
Administration Hunger
Action Center
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Ecotope Group
Tim Magee/David Baylon
Ecotope Group
2332 East Madison
Seattle, WA 98112
FUNDING
PERIOD OF PERFORMANCE
$19,000
10/77 - 1/78
Technical Summary
The objective of this is to develop a prototype green-
house which can be produced and marketed in an urban area.
This involves a marketing survey, prototype development
and demonstration, and public education on the use and feasi-
bility of solar greenhouses for heat and food production.
A-7
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PROJECT TITLE
SPONSOR
Solar Aquaculture/
Greenhouse
U.S.D.A. Agricultural
Research Service
Rural Housing Research
Unit
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Ecotope Group
Davis Straub/David Baylon
Ecotope Group
2332 East Madison
Seattle, WA 98112
FUNDING
PERIOD OF PERFORMANCE
$40,000
6/77 - 6/78
Technical Summary
Research activities center on a passive solar/aquaculture
greenhouse which includes a parabolic interior concentrator
to enhance heat collection and storage in a 5000 gal aqua-
culture tank. The greenhouse is located on Pragtree Farm in
Arlington, WA, a commercial organic farm. The greenhouse has
384 ft2, 1/2 of which is plant growing area and the balance
of which is the aquaculture/heat storage tank. A full instru-
mentation station monitored by a Motorola MC 6 800 minicom-
puter is being installed, including 3 solarimeters,
2 psychrometers and temperature probes.
The focus of this research will be to demonstrate the
feasibility of passive solar heating in greenhouse performance
and the potential feasibility of aquaculture ecologies inte-
grated into a greenhouse environment.
A-8
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PROJECT TITLE
SPONSOR
Solar Heating
Demonstration and
Testing Project
Portland General Electric
Company
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Various Contractors
Doug Boleyn
Portland General Electric
121 SW Salmon St.
Portland, OR 97204
FUNDING
PERIOD OF PERFORMANCE
19 77 Approximately
$100,000
1978 Tentatively $108,000
Continuing
Technical Summary
The objectives of PGE1s Solar Project are:
1.	to obtain "hands on" working knowledge of solar heat-
ing and cooling systems in actual buildings in the PGE
service area,
2.	to determine the effect of various solar heating systems
on Portland General Electric Company,
3.	to determine the possible future opportunities for PGE
in the solar energy field, and
4.	to make a "regional" contribution to the field of solar
heating in the Northwest. This recognizes that problems
and solutions are regional in nature.
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Specific tasks for this project include preparation of
public education material; economic analysis of various solar
heating and cooling systems; installation of solar instrumen-
tation systems at Chemeketa Community College Learning
Center, the Carroll House, the Boleyn House and the
Bishoprick House; and analysis of the data from these instru-
mented solar systems.
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PROJECT TITLE
SPONSOR
Solar Collector
Performance
Measurements
U.S. Department of Energy
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Pacific Northwest
Laboratory
Operated by Battelle
Memorial Institute
H. L. Parry
Pacific Northwest
Laboratory
P.O. Box 999
Richland, WA 99352
FUNDING
PERIOD OF PERFORMANCE
$13,000
1977 - 78
Technical Summary
The study will provide data to determine on an instan-
taneous basis the parameters (e.g. , ambient temperature,
spectral insolation, and wind) needed to choose the optimum
collector type (flat plate, concentration, hybrid, etc.) for
a given location. In addition, experience will be gained in
areas of insolation, climate effects, and solar collector
performance, and thus an educational tool will be available
for demonstrating solar principles to persons in the
Pacific Northwest.
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PROJECT TITLE
SPONSOR
Energy Efficiency and
the Food System
Washington State Office of
Environmental Education
PERFORMING ORGANIZATION
Canyon Park Junior
High School
King County Work
Training Program
Ecotope
Washington State Office
of Environmental
Education
CONTACT FOR ADDITIONAL
INFORMATION
Tony Angell, Supervisor
Washington State Office of
Environmental Education
Energy, Food, and You
Program
c/o Shoreline District
Offices
NE 15 8th and 20th Avenue NE
Seattle, WA 98155
FUNDING
$2,000
PERIOD OF PERFORMANCE
1977 -- ?
Technical Summary
King County students in junior and senior high schools
have been working on a unique heat storage experiment. They
have salvaged three old greenhouses and, using a passive
system of a 20-ton North wall and clear plastic water con-
tainers on the South side, have taken advantage of the sun's
heat. The object is to teach the students how to save energy
by growing their own food, to recycle materials to save
energy resources for the future, and to increase the North-
west growing season by using simple solar methods. This
program is part of a year long training session for Seattle
teachers (K-12) in the efficient use of energy resources.
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PROJECT TITLE
SPONSOR
Project Sunburst
U.S. Department of Energy
(solar system only)
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Olympic Engineering
Corporation
Charles Ripley, P.E.
Olympic Engineering
Corporation
30 70 George Washington Way
Richland, WA 99352
FUNDING
PERIOD OF PERFORMANCE
$633,000
Construction complete
Spring 1978
Technical Summary
A current Olympic Engineering Corporation project for
the Department of Energy is the design and installation of
a solar space heating, space cooling, and domestic water
heating system in a 14,400 square feet Project Sunburst
office building at Richland, Washington. The system is
designed to provide 71% of the space heating, 97% of the
space cooling, and most of the domestic water heating required
for year-round operation of the building. An array of 6,000
2
ft of roof-mounted General Electric flat plate collectors
supply energy through a heat exchanger to an underground
insulated 9,000-gal thermal energy storage tank. Hot water
to drive a 25-ton Arkla absorption chiller in the summer,
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and to supply hot water directly to 8 water-to-air coils
in the forced air duct work in the winter, is pumped from
storage on demand from 8 zone thermostats. The chiller
cools water in a 2,000-gal storage tank to supply cold
water to the same water-to-air coils in the summer. An
identical non-solar building on the same site offers the
advantage of determining the solar energy contribution by
comparing the electrical energy consumption of the solar
building with that of the control building. Final accep-
tance testing of the solar system is expected in early 1978.
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PROJECT TITLE
SPONSOR
Wind Energy Research
Project
Puget Sound Power Light
Snohomish County PUD
John Strickler, Jr.
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Various contractors
Bob Bannister
Puget Sound Power & Light
P.O. Box 353
Bellevue, WA 9 8009
FUNDING
PERIOD OF PERFORMANCE
Not available
1978 - 1981
Technical Summary
Puget Power in a joint venture with the Snohomish
County PUD and a private consultant, John Strickler Jr.,
is studying the practicality of wind generated electric
energy as a viable source of supplemental energy. Puget
Power is acting as project manager for the five-year pilot
project, Strickler, a retired aeronautical engineer,
designed the windmills. Each windmill is designed for an
electrical capacity of three kW.
The two primary objectives of this project are to
1) analyze the feasibility of wind energy as a supplemental
energy source, and 2) analyze the feasibility of supple-
mental wind energy applied to thermal storage—concrete
slab heating—for residential applications. If wind energy
is to ever become a major energy source, its costs must be
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kept at a minimum as compared to other energy sources.
For this reason one of the constraints on this project is
to develop the total system at the lowest reasonable price
by utilizing commercially available products where possible.
Monitoring equipment will be installed by Puget Power
to record data on the performance of the windmills at
Strickler's house and on the two heating systems in the
concrete floor. Data will be obtained over the next several
years to determine the practicality of wind-generated
electrical energy as a viable supplemental source of power.
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PROJECT TITLE
SPONSOR
Energy Conservation by
Solar Heating in a
Residence
Chevron Research Company
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Washington State
University
James S. Englund
Dept. of Mechanical
Engineering
Washington State University
Pullman, WA 99164
FUNDING
PERIOD OF PERFORMANCE
Not available
September 1977 to June 1979
Technical Summary
A residence which has been previously treated to
conserve energy in conventional ways is being fitted with
a space and water heating solar system. Instruments will
monitor the performance. The program is intended to demon-
strate further savings of fossil energy.
A complete report of the work, including system per-
formance, will be issued for widespread distribution at
the completion of the project.
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PROJECT TITLE
SPONSOR
Solar Collector
Comparison
City of Eugene, OR
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Eugene Water &
Electric Board
H. D. Artell
Eugene Water & Electric
Board
500 East 4th
Eugene, OR 97401
FUNDING
PERIOD OF PERFORMANCE
Not available
February 19 75 - July 19 76
Technical Summary
A total of eleven liquid flat plate collectors of
various designs were operated at constant discharge tem-
perature and the delivered energy compared to the solar
energy available on a daily basis. Results are expressed
as curves of solar energy versus energy output.
Contact H. D. Artell, Project Engineer, Eugene Water &
Electric Board for additional details and possibility of
obtaining copy of report.
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PROJECT TITLE
SPONSOR
Farmstead Utilization
of Solar Energy
Portland General Electric
Company
Pacific Power and Light
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Engineering Experiment
Station, Oregon State
University
Corvallis, OR 97331
Martin Hellickson
Department of Agricultural
Engineering
Oregon State University
Corvallis, OR 97331
FUNDING
PERIOD OF PERFORMANCE
$20,000
1978
Technical Summary
This project is an investigation of the use of a
solar collector in conjunction with a refrigeration com-
pressor heat recovery system to produce 110°F and 140°F
water for dairy farm operation. Results will be available
in January 19 79.
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PROJECT TITLE
SPONSOR
Solar Energy
Meteorological Research
and Training Program
U.S. Department of Energy
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Oregon State University
Corvallis, OR
University of Oregon,
Eugene, OR
Sciences
Oregon State University
Corvallis, OR 97331
E. W. Hewson
Department of Atmospheric
FUNDING
PERIOD OF PERFORMANCE
$1,000,000
1978 - 1983
Technical Summary
The U.S. Department of Energy has provided a 5-year
grant to the consortium of the Atmospheric Sciences Depart-
ment of Oregon State University (OSU) and the University of
Oregon Solar Energy Center (UO). This program will result in
a primary facility (OSU) with high quality radiation instru-
ments, meteorological tower, a mobile unit, and related
equipment; an academic year training program at OSU; a
series of public seminars and summer workshops (OSU and UO);
and an expansion of the University of Oregon's existing
radiation monitoring stations to include the other four
states in the region (Washington, Idaho, Montana, and
Wyoming).
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PROJECT TITLE
SPONSOR
The Incorporation of
Energy Conservation
Principles into the
Design of State
Buildings
State of Washington,
Department of Social and
Health Services
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
The Built Environment
Study Teaching and
Research Group
Institute for Environ-
mental Studies
University of Washington
Gordon B. Varey, AIA
Department of Architecture
University of Washington
Seattle, WA 98105
FUNDING
PERIOD OF PERFORMANCE
July 1977 to June 1978
$253,435.00
1976 - 1981
Technical Summary
Conservation Design is an interdisciplinary project
including faculty and students from Engineering, Archi-
tecture, and the Atmospheric Sciences. A computer program
(UWENSOL) has been developed that accurately reflects the
dynamic external influences on proposed building alternatives
such as insolation, air temperature and psychometric pro-
perties as well as the schedules of use in terms of internal
loads and selected or causally resulting temperatures and
humidity. It is capable of dealing with interactions between
several thermally interconnected spaces in the moderating
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effect of air movement in any spatial configuration and varied
illuination condition. The UWENSOL program is being tailored
to meet the needs of easy applications by practicing
architects in designing multi-room and multi-use structures.
A user handbook and set of guidelines is being prepared
oriented toward passive conservation in the Pacific Northwest.
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PROJECT TITLE
SPONSOR
Solectric House
Idaho Power Company
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Idaho Power Company
B. N. Schmidt
Idaho Power Company
P.O. Box 70
Boise, ID 83707
FUNDING
PERIOD OF PERFORMANCE
Not available
19 77 for a period up to
5 years
Technical Summary
This program is designed to obtain information for
evaluation and demonstration of solar space and water
heating for residential customers in Southern Idaho.
Commercially available solar collection equipment has been
installed. Metering equipment includes watt-hour and water
meters.
Data is analyzed each month comparing theoretical energy
requirements for space and water heating with metered energy
input. The balance is credited to solar input. Significant
information will be released as it becomes available.
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PROJECT TITLE
SPONSOR
Solar Heated Pre-Built
Home
U.S. Department of Energy
Boise Cascade Corp.
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Boise Cascade Corp.
R. A. Wilde
U.S. DOE
550 2nd St.
Idaho Falls, ID 83401
FUNDING
PERIOD OF PERFORMANCE
Approximately $350,000
1978 - 1980
Technical Summary
The objective of this project is to design, construct
and evaluate a solar heated factory-built home. The solar
collectors and distribution system will be designed to be
an integral part of the home.
Two prototypes will be built with one located in Boise,
Idaho and the other in Idaho Falls, Idaho. The different
climates of these two locations will provide a comparison of
the solar heating system performance under widely varying
conditions. System performance will be monitored for two
years.
This project is designed to produce a solar heated home
at a price within reach of a large segment of the home-buying
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public. Information about the project will be distributed by
U.S. Department of Energy Technical Information Center, Box 62,
Oak Ridge, Tennessee 37830.
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PROJECT TITLE
SPONSOR
Solar Water Heating
Demonstration Program
Pacific Power & Light
Company
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Pacific Power & Light
Company
W. R. Goldbach
Pacific Power & Light
Company
920 SW 6th Ave.
Portland, OR 97204
FUNDING
PERIOD OF PERFORMANCE
$25,100
1974 - 1978
Technical Summary
A domestic solar water heating program is currently
under way within the service territory of the Pacific
Power & Light Company. The program is designed to obtain
information for the evaluation of the suitability of using
solar assisted heating systems in the Pacific Northwest.
Commercially available collection equipment has been installed
in homes at Grants Pass, Pleasant Hill, and Tigard, Oregon;
Yakima, Washington; and Casper, Wyoming.
Instrumentation is providing magnetic tape records
of weather, solar insolation, and temperature. Because
of some delays in equipment ordering, the program will
most likely go beyond the original four-year schedule.
A progress report which summarized results through June
1977 is available.
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PROJECT TITLE
SPONSOR
Solar Research Project
Washington Water Power
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
University of Idaho
Moscow, ID
Washington State
Donald L. Olson
University
Pullman, WA
Washington Water Power
P.O. Box 3727
Spokane, WA 9 9 220
FUNDING
PERIOD OF PERFORMANCE
$100,000
1977 - 1978
Technical Summary
At the University of Idaho, several graduate students
have developed a solar collector which generates electricity
and heats water for domestic use. The tracking solar collec-
tor makes electricity to supply its own operating requirements
and has a surplus for other small electrical loads. Another
project developed at Idaho is a microprocessor computer
unit used to collect and anlyze solar data and statistics
from throughout the Pacific Northwest. Also being tested
on the Idaho campus are ways of installing solar panels to
achieve maximum results.
Nine miles away at Washington State University, archi-
tecture students are studying the "passive mode" of solar
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energy use. WSU will be developing recommendations for the
architectural community, emphasizing solar technology not
widely known today.
The Department of Mechanical Engineering at WSU has
installed several solar water heating units in Pullman.
These units will be used to relate the performance of solar
water heaters to energy saving, customer savings and utility
impact.
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PROJECT TITLE
SPONSOR
Solar Program
Energy Alternatives, Inc.
Moscow, ID
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
Advance Bldg. Technology
Group
Dept. of Architecture
University of Idaho
Prof. A. Eder
Dept. of Architecture
University of Idaho
Moscow, ID 83843
FUNDING
PERIOD OF PERFORMANCE
Not available
Continuing
Technical Summary
The heat transfer dynamics of rock-filled channels
cut in the earth will be tested. The ultimate goal is to
develop low cost earth/rock storage systems for solar energy
use. The system has promise when used for long term, annual
cycle, solar storage.
A "V" fin air type (patent applied for) solar collector
is being tested, using NBS performance standards. The test
equipment will be available for testing of other air type
solar collectors.
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PROJECT TITLE
SPONSOR
TERA ONE
Pacific Power &
Light Company
PERFORMING ORGANIZATION
CONTACT FOR ADDITIONAL
INFORMATION
Pacific Power &
Light Company
W. R. Goldbach
Pacific Power & Light Co.
9 20 SW 6th Avenue
Portland, OR 97204
FUNDING
PERIOD OF PERFORMANCE
$350,000
1977 - Continuing
Technical Summary
TERA ONE is an energy conservation laboratory, designed
to promote and research energy conservation.
Objectives
1.	Promote public education and awareness of energy con-
servation with the cooperation of OMSI.
2.	To objectively test and evaluate energy conservation
systems, products and principles in a residential
structure.
Systems
1.	An aesthetically pleasing appearance
2.	Energy conservation landscaping
3.	Maximum space utilization
4.	Double glazing and minimum window area
5.	Use of natural light where possible
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6.	Minimum air infiltration
7.	Use of energy efficient appliances
8.	Minimize use of water
9.	Reclamation of waste heat from appliances where
possible
10.	Use of various insulation materials
11.	Partial earth roof
12.	Use of passive solar wherever possible
13.	Greenhouses for aesthetics and heating/cooling
14.	Natural heating and cooling
15.	An energy efficient fireplace
16.	A solar collection system with storage
17.	a water-to-water staged heat pump
18.	Maximum use of natural ventilation
19.	An energy efficient heating/cooling system
20.	A control system to (optimize and) minimize the
energy usage
All parameters affecting this project will be recorded
with a data logger. Data will be reduced, and available
quarterly starting December 19 77.
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PROJECT TITLE
Study of a Regionally
Adapted Residential
Solar Heating and Heat
Pump System
SPONSOR
Department of Energy
PERFORMING ORGANIZATION
Mathematical Sciences
Northwest, Inc.
CONTACT FOR ADDITIONAL
INFORMATION
Robert Taussig
MSNW
P.O. Box 1887
Bellevue, Washington
(206)827-0460
98009
FUNDING
$30,000
PERIOD OF PERFORMANCE
November 1977 - April 1978
Technical Summary
Mathematical Sciences Northwest, Inc. (MSNW) is carry-
ing out an analysis and assessment of performance data from
the Seattle City Light Project Weathervane with the object
of providing a data base for regional solar heating and heat
pump systems. Project Weathervane is a house which has been
retrofitted with solar collectors, a water energy storage
tank, and a heat pump which takes heat from the storage tank.
Initial analysis has already been performed by Seattle City
Light using selected portions of the data. MSNW has devel-
oped a more complete computer data base for a full heating
season. This same data will be used to test the accuracy
of one or more solar heating computer simulation models.
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The results of the computer simulation will be analyzed
to determine the code which does the best job of repro-
ducing the actual data and to understand the code charac-
teristics which predict operations differing from actual
performance.
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APPENDIX B
Glossary of Terms
and Abbreviations
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ASHRAE
Acronym for the American Society of Heating, Refrigerating,
and Air Conditioning Engineers.
British Thermal Unit (Btu)
A unit of measurement (English system) equivalent to the
heat (energy) necessary to raise the temperature of one
pound of water one degree fahrenheit. In terms of a popular
reference, the amount of heat produced by the complete
burning of a wooden kitchen match is about equal to 1 Btu.
Calorie
A unit of measurement (metric system) equivalent to the
amount of heat (energy) necessary to raise the temperature
of one gram of water one degree centigrade. One Btu equals
252 calories.
Degree day-heating
A measure of temperature as it affects energy demand for
space heating. For any one day, it is equivalent to the
difference in degrees between the mean temperature for the
day and 65°F. The greater this difference, the colder the
day, and the greater the heating demand.
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Demand
In energy analysis, the rate at which energy is delivered to
a consumer. A high demand period, for a utility is one in
which a relatively large amount of energy must be supplied
during a relatively short time.
Insolation
The rate of delivery of solar energy on a flat surface.
Load
The amount of power delivered. For electrical utilities,
the load is numerically equal to the' demand.
Load Factor
The ratio of average load to peak load during a given time
period.
Greek letter used in scientific literature to indicate one-
one millionth of a quantity (10 ^). Used in Chapter II as a
measure of light wave length to indicate "microns" which are
10~^ meters.
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Power
The rate of energy use.
Watt
A unit of power. Equals 3.4 Btu's per hour.
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