\
v/
C
The Role of Distributed Generation and
Combined Heat and Power (CHP) Systems
in Data Centers
U. S. Environmental Protection Agency
Combined Heat and Power Partnership
SEPA COMBINED HEAT AND
POWER PARTNERSHIP
August 2007
-------
Foreword
The U.S. Environmental Protection Agency (EPA) Combined Heat
and Power (CHP) Partnership is a voluntary program that seeks to
reduce the environmental impact of power generation by
promoting the use of CHP. CHP is an efficient, clean, and reliable
approach to generating power and thermal energy from a single
fuel source. CHP can increase operational efficiency and decrease
energy costs, while reducing the emissions of greenhouse gases,
which contribute to global climate change.
The CHP Partnership works closely with energy users, the CHP
industry, state and local governments, and other stakeholders to
support the development of new projects and promote their energy,
environmental, and economic benefits. The partnership provides
resources about CHP technologies, incentives, emission profiles,
and other information on its Web site at: www.epa.gov/chp.
Report prepared by: Energy and Environmental Analysis, Inc., an ICF International Company, and
Eastern Research Group, Inc. (ERG) for the U. S. Environmental Protection Agency, Combined Heat and
Power Partnership, August 2007.
Note: This paper was originally written and submitted as Chapter 6 in the Report to Congress on Server and Data
Center Energy Efficiency, as required by Public Law 109-431.
-------
Contents
1 Overview 1
2 Data Center Energy Use Characteristics 3
2.1 Power Capacity Requirements 3
2.2 Power Quality Requirements 4
2.3 Air Conditioning Needs 5
3 Benefits of Distributed Generation and Combined Heat and Power for Data Centers 8
3.1 Reduced Energy Costs 8
3.2 Increased Reliability 10
3.3 Facility Expansion 11
3.4 Economic Development 12
3.5 Increased Energy Efficiency 12
3.6 Emissions Benefits 14
4 Distributed Generation Applications at Data Centers 17
4.1 Standby/Backup 17
4.2 Continuous Prime Power 17
4.3 Combined Heat and Power 19
4.3.1 Case Studies of Combined Heat and Power Applications at Data Centers . 20
5 Issues Affecting Implementation of Distributed Generation at Data Centers 23
6 References 25
List of Tables
Table 1. Energy Cost Savings Comparison for Combined Heat and Power in Data Centers 9
Table 2. Effect of Distributed Generation/Combined Heat and Power and Multiple Utility Feeds
on System Reliability 11
Table 3. Emission Benefits of Combined Heat and Power 15
Table 4. Emission Benefits of Fuel Cell Backup Power 16
Table 5. Combined Heat and Power Installations in Data Center and Communications Facilities
20
Table A-l. Fuel Cell Installations in Data Centers and Related Premium Power Applications... 26
List of Figures
Figure 1. Average Energy Usage Intensity of Select Data Centers, 2003 4
Figure 2. Power Layout for a 25,000-Square Foot Data Center in San Diego, California 5
Figure 3. Typical Data Center Air Conditioning (Hot Aisle, Cold Aisle) Layout 6
Figure 4. Server Rack and Air Conditioning Layout for a 10,000-Square Foot Data Center (500
watts/square foot) 7
Figure 5. Energy Use in the U.S. Electric Power Sector Shows Energy Conversion Losses 13
Figure 6. Combined Heat and Power Efficiency Advantage Compared to a Central Power Plant
and Onsite Boiler 14
Figure 7. Prime Power Configuration at Hamilton Sundstrand Data Center 18
11
-------
1 Overview
This report reviews how distributed generation (DG) resources such as fuel cells, reciprocating
engines, and gas turbines—particularly when configured in combined heat and power (CHP)
mode—can offer powerful energy efficiency savings in data centers, especially when integrated
with other energy efficiency measures.
The growing need for reliable, cost-effective power is a key issue for the data center industry, as
indicated as follows:
• Electricity consumption for servers (includes servers and cooling and auxiliary
infrastructure) doubled in the United States between 2000 and 2005 and represents about
1.2 percent of total U.S. power use (Koomey, 2007).
• A single data center can house hundreds or thousands of servers. Continued growth in the
server population is expected as companies look to expand data center capabilities.
• As server densities also increase to squeeze more computing power into less space, the
energy consumption estimates of a single server rack can exceed 20 kilowatts (kW).
• According to AFCOM (2006), power failures and limits on power availability will halt
data center operations at more than 90 percent of all companies at some point over the
next five years.
• A survey conducted by Ziff-Davis Media (2006) revealed that more than 70 percent of
operators identify information technology power and cooling as a primary issue in data
center management.
• With rising energy costs and fears of inadequate energy supply and reliability on the
horizon, businesses are looking for efficient solutions to address these trends.
DG resources in CHP systems that use waste heat to provide cooling can offer the greatest
benefits and lowest paybacks throughout the supply chain and are ideally suited to the steady
power and cooling loads of data centers. For instance, in a CHP configuration, fuel cell systems
can have paybacks approaching 10 years when state and utility incentives are included; gas
turbine and microturbine systems can have financial paybacks of less than five years. Clean
DG—whether fuel cells or other clean energy prime movers—can also provide environmental
benefits regionally, in the reduction of criteria pollutants that otherwise would be emitted by
grid-generated electricity, and globally, in the reduction of greenhouse gas emissions. In addition
to these financial and environmental benefits, DG systems can also significantly improve the
reliability of power supply for data centers.
The DG technologies discussed in this report include fuel cells (typically 10 kW to 2 megawatts
[MW] in size), microturbines (30 kW to 250 kW), gas turbines (500 kW to 20 MW), and
reciprocating engines (100 kW to 3 MW). Solar photovoltaic power (PV) could be a
supplementary source of power as well, but due to the intermittent and as-available nature of PV,
it would not be considered a reliable, primary source of power for a data center. The focus of this
report is on DG that can be dispatched on demand to support both the energy and reliability
needs of data centers. It is also important to note that the optimal use of DG/CHP in data centers
-------
requires that all cost-effective efficiency improvements in server and building operations be
implemented before considering a DG/CHP investment.
The report is organized into the following sections:
o Chapter 2 - Data Center Energy Use Characteristics: Describes the power usage,
reliability, and quality requirements and air conditioning requirements that affect the
application of DG and CHP in this market.
o Chapter 3 - Benefits of Clean Distributed Generation and Combined Heat and
Power: Provides a discussion of the benefits of DG/CHP to data center operators and
the rest of the energy supply chain.
o Chapter 4 - Distributed Generation Applications at Data Centers: Describes in what
applications DG/CHP can be used at data centers and includes case study examples of
three CHP applications.
o Chapter 5 - Issues Affecting Implementation of Distributed Generation at Data
Centers: Describes barriers that are limiting the widespread application of DG/CHP in
data centers and areas where the U.S. Environmental Protection Agency (EPA) CHP
Partnership can help.
-------
2 Data Center Energy Use Characteristics
Data centers are characterized by very high energy utilization intensities, and the internal heat
load creates a nearly constant demand for air conditioning to maintain equipment within a
narrow range of temperature and humidity necessary for proper operation. This chapter describes
common features of data centers as they relate to power consumption and power security and
quality requirements.
2.1 Power Capacity Requirements
Data centers have much higher energy utilization intensities (20 to 100 watts per square foot
[W/s.f.]) than typical commercial buildings, which average 2 W/s.f. based on annual
consumption data for all commercial buildings (EIA, 2006). Nationally, data centers represent
approximately 1.2 percent of total U.S. power use—or about 5,000 MW (Koomey, 2007). The
energy consumption estimates of a single-server rack can exceed 20 kW (Hughes, 2005).
As Internet commerce and traffic began exploding in the late 1990s, the industry experienced
general concern that power demand in data centers would become a significant share of power
demand in the United States and other countries. A Lawrence Berkeley National Laboratory
(LBNL) benchmarking study (2003) found considerable variation in power use among data
centers depending on their design and intended use (see Figure 1). The LBNL study found that
energy usage intensity averaged 25 W/s.f. across the 14 examined data centers and projected
increased energy intensity to 39 W/s.f.
In fact, however, predictions of runaway energy consumption in data centers have not come true.
Energy intensities in data centers have been increasing but at a much slower rate than originally
expected. While the energy density of individual rack components that make up data center
equipment has increased greatly, rated loads for server equipment tend to be much higher than
typical usage levels. Additionally, typical facilities contain a mix of high and low power
consumption equipment. Some designers predict a 500-W/s.f. data center in just a few years
(Hughes, 2005), but these claims are not universally accepted within the industry.
-------
Figure 1. Average Energy Usage Intensity of Select Data Centers, 2003
Average Projected Load: 39.3
6 7 8 9 10
Facility Identifier
11 12 13 14
[Current Computer LoadDProjected Computer Load
Source: LBNL, 2003
For new or expanding data center facilities, power requirements can range from 1 MW up to 50
MW. In some circumstances, electric utilities cannot provide this level of power without
considerable advance notice and planning—on the order of one to two years or more.
Compounding the difficulty of receiving needed capacity in a timely manner, data centers have
developed a reputation for requesting much more power than they actually use and are therefore
sometimes charged for all of the upgraded facilities requested (e.g., substations, transformers,
power lines).
2.2 Po wer Quality Requirements
A continuous supply of premium power is essential to all data centers to avoid equipment
downtime. For such highly critical equipment, the cost of being offline, even for a short period,
can run well into the millions of dollars.
Figure 2 shows a schematic of the power supply for a 25,000-s.f. co-location data center in San
Diego. The system is an example of 2N architecture—all required power services are backed up
into two separate and redundant systems that are each capable of meeting the entire facility load.
The facility has two separate 4,000-amp, 480-volt feeds from the utility—each to an individual
master supply bus (MSB). This system provides automatic switching between the two
independent transformers located on the property. In the event of an extended power outage,
diesel generators capable of supplying either of two independent emergency supply buses (ESBs)
provide input power to the facility. Three thousand five-hundred gallons of onsite diesel stored
on the facility are capable of providing fuel for more than 24 hours at maximum power. The
system can also be refueled while operating (American Internet Services, n.d. (a)).
-------
The facility has 1 MW of redundant uninterruptible power supply (UPS) power and a fully
redundant 2,400-amp, 48-volt, positive ground direct current (DC) battery power plant and
distribution system. UPS power is fed into redundant power distribution units (PDUs) and from
there into remote power panels (RPPs). Each RPP is monitored to the circuit breaker level to
ensure early warning overload protection (American Internet Services, n.d., (a)).
Figure 2. Power Layout for a 25,000-Square Foot Data Center in San Diego, California
Tie Control
System
Bus
UPS-X
500 kW
Tie-MSB 1
4000 AMP
Tie-MSB2
4000 AMP
System
Bus
UPS-Y
iSQQ kW
Battery
Bus
UPS Bypass
Panel
Battery
Bus
PPUPS-X-
Battery Cabinets
DPUPS-Y*
PDLI-X1
225 kW
PDU-X2
225 kW
PDU-Y2
I 225 kW
RPP
G
RPP
H
RPP
E
RPP
F
RPP
I
RPP
J
Source: American Internet Services, n.d. (b)
2.3 Air Conditioning Needs1
The primary goal of data center air conditioning systems is to keep the server components at the
board level within the manufacturer's specified temperature/humidity range (Hughes, 2005). Air
Information in this section is from Hughes, 2005.
-------
conditioning is critical because electronic equipment in a confined space generates much excess
heat and tends to malfunction if not adequately cooled. Air conditioning systems also help keep
humidity within acceptable parameters. The presence of too much humidity could cause water to
begin to condense on internal components; with too little humidity, static electricity can damage
components. Generally, temperature should be kept around 68°F to 72°F; humidity should be
kept between 35 and 65 percent relative humidity. To put the cooling load in perspective, an
IBM series Bladecenter server requires 24 kW of power ina2x3.5x6 foot space. All of this
power is converted to heat. Therefore, each of these racks requires 6.8 tons of air conditioning.
The typical configuration of a data center air conditioning system is called a hot aisle/cold aisle
layout (see Figure 3). The computer rooms are on a raised floor that serves as the conditioned air
delivery system.2 Computer room air conditioning units fCRACs) deliver cold air under the floor
in alternating aisles; the hot air is removed overhead.
Figure 3. Typical Data Center Air Conditioning (Hot Aisle, Cold Aisle) Layout
HOT AISLE/COLD AISLE APPROACH
Pndtior \
Conditioning Unit
Precision AH
Conditioning UniH
Source: Pouchet, 2007
Figure 4 illustrates the number of CRAC units required for a 10,000-square foot data center at
500 W/s.f As power densities go up, the space required for air handling and air conditioning
equipment also goes up, reducing the available floor space for the servers. CRAC units typically
use water-cooled condensers that are tied into cooling towers for heat removal. In other
configurations, the CRACs are replaced by computer room air handling units (CRAH) that are
tied into a central water chiller.
2 In fact, it is standard terminology to refer to the actual square footage of a data center that is devoted to computer
equipment as the raised floor area.
-------
Figure 4. Server Rack and Air Conditioning Layout for a 10,000-Square Foot Data Center
(500 watts/square foot)
Source: Hughes, 2005
Integrating the cooling loads with a combined heat, cooling, and power system would require the
use of a central chiller and CRAHs. Alternately, water cooling for the racks could meet cooling
requirements and would be would be more space and energy efficient than traditional systems.
Water cooling design would also be tied into a central chiller system using the heat from a CHP
system.
-------
3 Benefits of Distributed Generation and Combined Heat
and Power for Data Centers
DG and CHP applied in data centers can provide cost savings to the facility operator in the form
of:
• Reduced energy-related costs and enhanced economic competitiveness—from reduced
fuel and electricity purchases, resulting in lower operating costs.
• Increased reliability and decreased risk from outages—due to reliable onsite power
supply.
• Increased ability to meet facility expansion timelines—by avoiding the need for utility
infrastructure upgrades.
In addition to these cost savings, DG/CHP provides the following benefits to the energy supply
chain:
• Increased economic development value—through energy cost savings, businesses can be
more economically competitive in a global market, maintaining local employment and
economic health.
• Increased energy efficiency from generating electricity and useable thermal energy from
a single fuel source.
• Reduced emissions of greenhouse gases—reduced fuel use results in lower levels of fossil
fuel combustion and reduced emissions of carbon dioxide (CC^).
• Reduced emissions of criteria air pollutants—reduced fuel use and cleaner technology
results in lower air emissions of carbon monoxide (CO), nitrogen oxides (NOx), and
sulfur dioxide (802).
• Increased reliability and resource adequacy for the grid—customer-sited generation can
provide support and stability to the distribution grid and reduce or defer the need for
regional power plant and transmission construction.
3.1 Reduced Energy Costs
Due to their very high electricity consumption, data centers have high power costs. Installing
CHP systems with absorption cooling can often reduce energy costs by producing power more
cheaply on site than can be purchased from the utility supplier. In addition, waste heat from the
power generation can drive absorption chillers that displace electric air conditioning load.
Table 1 shows simple annual savings and paybacks for four actual CHP systems installed in
California and the Northeast. Capital costs for the first three DG systems were based on average
capital costs for completed installations under the California Self Generation Incentive Program
(SGIP), plus an assumed capital increase for absorption cooling of $l,200/ton based on the
cooling capacity required for each system. Capital costs for the gas turbine were estimated based
on an estimated price for a complex installation with a double effect absorption chiller
-------
($350/ton), selective catalytic reduction (SCR) and CO control with a continuous emissions
monitoring system (CEMS) and average U.S. construction costs.
Given the performance of these systems and a favorable differential between the price of fuel
and the price of electricity (called the spark spread) that can be found in California or the
Northeast, annual energy cost savings of between $239/kW and $697/kW are available. For
example, one data center in New York recently installed a 1.4 MW fuel cell CHP system that
saves the company $680,000 per year on its energy costs.
Fuel cell DG systems offer many attractive qualities, such as DC power output, for use in data
centers. But fuel cells, as a new-market entrant, attract a price premium over more traditional DG
systems. So while DG systems based on traditional gas turbine or engine technologies can be
considered cost effective without incentives, fuel cells, in some cases, will need financial
incentives to be cost effective. Very generous incentive programs are available in some areas,
such as the California SGIP fuel cell incentive of $2,500/kW, which can be combined with the
federal tax credit for fuel cells of $l,000/kW. Microturbines are eligible for smaller incentives
under both of those programs.
Table 1. Energy Cost Savings Comparison for Combined Heat and Power in Data Centers
CHP System
Capacity, kW
Heat Rate, Btu/kWh
Capital Cost, $kW
Total Capital Cost
O&M Cost*, $/kilowatt hour
Annual O&M Cost
Annual Gas Cost**
Annual Avoided Electricity**
Savings
California SGIP
Federal Fuel Cell Tax Credit
Net Capital Cost
Net Unit Capital Cost, $/kW
Payback without Incentives,
years
Payback with Incentives,
years
Molten
Carbonate
Fuel Cell/
Chiller
1,000
8,060
$7,238
$7,238,000
$0.032
$266,304
$503,065
($1,103,497)
($2,500,000)
($1,000,000)
$3,738,000
$3,738
21.7
11.2
Phosphoric
Acid Fuel Cell/
Chiller
200
9,480
$7,805
$1,560,900
$0.029
$48,268
$118,339
($220,756)
($500,000)
($200,000)
$860,900
$4,305
28.8
15.9
Microturbine/
Chiller
Package
200
14,300
$4,088
$817,600
$0.022
$36,617
$178,507
($354,668)
($160,000)
($40,000)
$617,600
$3,088
5.9
4.4
Gas Turbine/
Chiller
3,364
13,930
$2,312
$7,778,200
$0.022
$615,895
$2,924,767
($5,153,526)
($800,000)
$6,978,200
$2,074
4.8
4.3
*Operations and maintenance (O&M) costs are based on having an annual service contract in place, as is typical; no
facility staff would be required to provide system maintenance or service.
**Based on gas price of $7.50/million British thermal units (MMBtu) and electricity price of $0.13/kWh reflective
of electricity price in California and the Northeast.
-------
3.2 Increased Reliability
As described in Chapter 2, data centers require both high quality and extremely reliable power.
Of all customer types, data centers, telecommunication facilities, and other mission-critical
computer systems have the highest costs associated with power outages or lapses in power
quality, ranging from $41,000 for cellular communications to as high as $30 million per minute
for data center operations during peak periods. (Bryson, et al., 2001; Ziff-Davis Media, 2006);
Digital Realty Trust, 2007).
Data centers almost always have UPS systems to condition power and eliminate momentary
outages, sags, surges, and other deviations from a clean, in-phase sinusoidal power signal. Data
centers often have more than one utility feed and associated seamless switching equipment to
increase the reliability of service. Battery backup is generally used to provide a short term outage
ride-through of a few minutes to an hour. Longer term outages are typically handled with
standby diesel generators.
Onsite power generation, whether it is an engine, fuel cell, microturbine, or other prime mover,
supports the need for reliable power by protecting against long-term outages beyond what the
UPS and battery systems can provide. DG/CHP systems that operate continuously provide
additional reliability compared to emergency backup generators that must be started up during a
utility outage. Backup generators typically take 10 to 30 seconds to pick up load in the case of an
outage. The increased reliability provided by continuously operating DG/CHP can be used to
reduce the amount of battery backup that is typically designed into premium secure power
systems. For example:
• A DG system that is already running during a grid power disturbance does not need to be
started. Therefore, the likelihood of a non-start is eliminated.
• A continuously operating DG system serves the function of a second power feed,
significantly reducing non-available power times and reducing the need for battery
backup.
• A continuously operating DG system can provide voltage support for the facility,
reducing the likelihood of voltage sags and other power quality disturbances from the
grid.
The availability factor3 of DG/CHP systems is an important component in determining the
overall system reliability. The most recent comprehensive report of DG/CHP availability was
conducted for Oak Ridge National Laboratory in 2003 (Energy and Environmental Analysis,
2004). Of the systems studied, reciprocating engines showed availability factors averaging 96 to
98 percent. Gas turbines had availability factors from 93 to 97 percent. Fuel cells, which are a
new market entrant, have demonstrated the potential to achieve comparable availability factors
as the sales and service infrastructure matures in the fuel cell market.
3 The availability factor is the proportion of hours per year that a unit "could run" (based on planned and unplanned
maintenance) divided by the total hours in the year.
10
-------
Reliability of power supply to the facility can be increased by using parallel utility feeds and
onsite DG/CHP generation (see Table 2). A typical onsite DG/CHP system, as described
previously, could have an availability factor of 97 percent; a utility service feed availability is
roughly 99.7 percent. The availability of power with onsite DG/CHP plus one independent utility
feed would therefore be 99.97 percent, resulting in 43 minutes of expected outages per year.
With two independent utility feeds plus CHP, the availabilities would be at a level of 99.99998
percent, with only 7 seconds of expected outages per year. These short-term power supply
outages can be handled with onsite energy storage, typically batteries.
Table 2. Effect of Distributed Generation/Combined Heat and Power and Multiple Utility
Feeds on System Reliability
Power Source
Utility Feed 1 (UF 1)
Utility Feed 2 (UF 2)
DG/CHP
System Availability With
UF 1 + DG/CHP
UF1 +UF2
UF1 + UF2 + DG/CHP
Availability
99.7%
99.7%
97.0%
Multiple Feeds
99.97%
99.999%
99.99998%
Outage Time Per Year
24 hours
24 hours
263 hours
43 minutes
4 minutes
7 seconds
DG/CHP can increase reliability and resource adequacy for the power grid as a whole, not just
for the facility operator. Rapid growth in local power demand can create localized shortages of
power and impact power quality and reliability of the grid. Considerable concern emerged about
the concentration of data centers in the Silicon Valley area of California during the power and
fuel crises of 2001. The problems led to local concerns of pollution from overuse of diesel
generators and to migration of new and some existing data centers out of the region in search of
more reliable power supplies. Based on the ability of utilities to expand supply, transmission, and
substation capacity, it could take several years before such shortages are eliminated. DG/CHP
can reduce or delay infrastructure investments, making the grid more reliable for all customers.
3.3 Facility Expansion
Developing onsite power sources provides data center operators with increased flexibility in both
the expansion and design of new facilities. Upgrading older, smaller data centers with new
equipment can require a large increase in power demand to the facility that might not be able to
be met by the utility in the near term. Incorporating continuous prime power DG/CHP options
can facilitate expansion and facility development on a more rapid schedule than can sometimes
be possible by relying solely on the existing utility grid. Minimizing external power demand also
reduces additional utility infrastructure requirements and associated costs that might be required
for new or expanded facilities.
11
-------
3.4 Economic Development
By reducing operating costs and providing other economic value to a facility, such as reduced
outage costs, the facility becomes more economically competitive. This economic development
value can be important to facilities that are competing on a global basis. Reduced operating costs
translate into greater profitability and more competitive pricing of services.
Increasing the economic competitiveness of a facility's operation benefits not only the facility
operator but also the employees and the surrounding economy. Money generated by the facility
in terms of wages and materials purchased creates a multiplier effect for the local economy.
3.5 Increased Energy Efficiency
Energy efficiency is valued for a number of reasons: reducing dependence on fossil fuels,
decreasing emissions of greenhouse gases and other air pollutants, reducing pressure on energy
prices, and increasing economic viability and sustainability.
In the United States as a whole, nearly 40 quads4 of primary resource energy are consumed each
year to generate electric power. For the most part, this energy is released in the form of heat that
provides the motive force to drive the electric generators. Of the 40-quad energy input that goes
into electric power generation nationally (Figure 5), about 26 quads of heat energy literally goes
up the stack in the form of heat losses. With large central station power plants located far away
from demand centers, there is no way to utilize or economically transport this heat energy—it is
simply wasted. The energy content of this unutilized resource is equal to the U.S. annual imports
of oil. To put this quantity in further perspective, it is more than equal to the entire energy
requirements of Japan, the fourth largest energy user in the world.
As shown in the figure, roughly two-thirds of the energy input is released as heat to the
environment. Even the most efficient thermal electric generation process available today releases
about 40 to 45 percent of its energy as waste heat. In fact, central station power generation
creates even more losses. In addition to the heat losses, about 5 to 10 percent of the electricity
generated is lost and converted back to heat as a result of resistance losses in the transmission
and distribution (T&D) system. The alternative to this approach is to generate electricity at or
near the customer load centers so that the heat energy can be used by industries, commercial
buildings, and other users. In addition, with distributed energy resources, T&D line losses are
eliminated.
4 One quad = one quadrillion, or 1015, British thermal units (Btu) and is roughly equivalent in energy to 1 trillion
cubic feet of natural gas.
12
-------
Figure 5. 2006 Energy Use in the U.S. Electric Power Sector Shows Energy Conversion
Losses
Fo
Fu
2B
t j
sail
els
80
Conv
Lo-s
28
arston
SeS
71
Consumed
To Generate
EJectriciiy
41.27
-ear Electric Power
8,21
*#**~
Renewable Energy 4,28
Gross „
Generation"
of Eiectrickv
14,56
J
t
Generation
of Electricity
13 S3
1
=-SS=
— 1 —
End
Use
13.03
I
Retail _,-.-.,
Sates T~— ^
12.51 c*niJ«i»tS
1 ^=
P;ant Lsee 3.73
iT & D Losses'
i 31
Other6
Net Impons
-w . of Electr-oiq
Unaccounted for Q Q,g
Source: Energy Information Administration, 2007
The average efficiency of fossil-fueled power plants in the United States is 33 percent and has
remained virtually unchanged for four decades. This means that two-thirds of the energy in the
fuel is lost—vented as heat—at most power plants in the United States. In addition to heat losses,
about 5 to 10 percent of the electricity generated by central plant power stations is lost before it
reaches an end user as a result of resistance in the T&D system.
The alternative to this approach is to generate electricity at or near the customer load centers to
avoid line losses and use the heat energy resulting from electric generation. By using waste heat
recovery technology to capture a significant proportion of this wasted heat, CHP systems
typically achieve total system efficiencies of 60 to 80 percent, compared to only 49 percent for
producing electricity and thermal energy separately (see Figure 6). In data centers where the
thermal load is almost entirely cooling rather than heating, CHP can still provide an overall
efficiency advantage. The waste heat from the generator is used in absorption chillers to produce
cooling, which displaces electricity-powered electric chillers rather than displacing direct fuel
purchases for heating. In addition to the electricity produced by the generator, the total electricity
displaced by a combined cooling and power system can be up to 35 percent more than the onsite
generator capacity. Therefore, the total electricity provided and displaced by a combined cooling
and power system can be up to 135 percent of the onsite generator capacity.
13
-------
Figure 6. Combined Heat and Power Efficiency Advantage Compared to a Central Power
Plant and an Onsite Boiler
Conventional
Generation
Power / '' \ 1
Station Fuel ~ • A
98 Units Fuel J2L
f\ EFFICIENCY:
154 units FueiS 31°4
\/ EFFICIENCY:
56 Unite Fuel 80%
**~ j— Heat r*
Boiler 1
yittfi/:- OVERALL
*I5I ./a
Combined
Heat & Power
5 MW Natural Sas
Combustion Turbine
30 ' •:W"" !
Urits " - M i
Electncitw • "*• "*'
: Cornt
i Heat &
: Cr"
"*1 UnFts : "^ Hf;<4* * —
Steam ' ~
Priwer ''100 Units Fuel
P \ I
P \i
TKO/: OVERALL
•f;*i /P^MFPICIEHev^
3.6 Emissions Benefits
Data centers have very low site emissions, but their high energy intensity results in a large
emissions signature from a source perspective (i.e., the utility's emissions to produce electricity
for the data center). CHP systems reduce emissions of criteria air pollutants—CO, NOx, and
SC>2—through increased efficiency and the use of cleaner technologies. Emission reductions can
be particularly significant when state-of-the-art CHP equipment replaces outdated and inefficient
existing equipment (generally used for backup power) at the site. In fact, fuel cells have such low
emissions that they can emit fewer criteria pollutants in a year as the primary power source for a
data center than a diesel generator will emit in 24 hours operating as a backup generator (see
Tables 3 and 4). CHP also reduces emissions that contribute to global climate change; increased
efficiency of fuel use allows facilities to achieve the same levels of output with lower levels of
total fossil fuel combustion, reducing emissions of CC>2.
Table 3 compares annual emissions from four CHP options with central station generation:
1. 1,000-kW molten carbonate fuel cell with a double effect absorption chiller.
2. 200-kW phosphoric acid fuel cell with a single effect absorption chiller utilizing roughly
half of the available thermal energy from the system.
3. 200-kW microturbine system with a double effect absorption chiller.
4. 3,400-kW gas turbine system with a double effect absorption chiller and emissions after
treatment (SCR and CO reduction) with a continuous emissions monitoring system.
The CHP emissions factors are shown on a per unit of power output basis and incorporate a
credit for the displaced emissions from avoided air conditioning load met by the absorption
chillers. The CHP emissions are compared to the average emissions from fossil-based power
14
-------
generation in the United States5, Each of the four systems show reductions in NOx, 862, and
CC>2, compared with the average for central fossil-based power generation.
Table 3. Emission Benefits of Combined Heat and Power
Characteristics
Capacity, kW
Heat Rate, Btu/kWh
Combined Heat and Power
Molten
Carbonate
Fuel Cell/
Chiller
1,000
8,060
Phosphoric
Acid Fuel
Cell/Chiller
200
9,480
Microturbine/
Chiller
Package
200
14,300
Gas
Turbine/
Chiller
3,364
13,930
Central Power
U.S. Fossil
Power
Average*
CHP Emissions Factors (for generated electricity minus avoided air conditioning emissions)
NOX, Ib/MWh
SO2, Ib/MWh
CO2, Ib/MWh
0.0058
0.0003
848
0.0273
0.0003
998
0.2583
0.0003
937
0.0751
0.0376
1056
N/A
N/A
N/A
Annual Emissions (based on 8,760 hours/year)
NOX, Ib/MW-year
SO2, Ib/MW-year
CO2, tons/MW-year
51
2.36
3,716
239
2.77
4,370
2,262
2.60
4,103
658
329
4,626
21,725
44,501
6,899
*Based on 2000 eGRID emissions data.
Table 4 shows a comparison of two backup power options—a proton exchange membrane
(PEM) fuel cell and a standard diesel engine.6 The table shows that emission reductions are
significant from switching to a PEM fuel cell from a diesel engine, even if only in backup power
mode. NOx and 862 emissions from a fuel cell are less than 1 percent of those from a diesel
engine, and CC>2 emissions are 30 percent less with a fuel cell than a diesel generator.
5 Combustion-based power generation is power generated from fossil fuels, biomass, and waste fuels. Nuclear,
hydro, solar, and wind power are not included because these sources would typically not be displaced by DG.
6 Diesel technology emissions can be reduced through the use of low-sulfur diesel fuel and incorporation of engine
modifications and exhaust after-treatment. These technologies are being developed for the transportation market, but
they are not currently being used for standby engines.
15
-------
Table 4. Emission Benefits of Fuel Cell Backup Power
Characteristics
Capacity, kW
Heat Rate, Btu/kWh
PEM Fuel Cell
150
9,750
Diesel Generator
600
10,000
Emission Factors (generated electricity)
NOX, Ib/MWh
S02, Ib/MWh
C02, Ib/MWh
0.100
0.006
1,170
20.282
2.900
1,650
Annual Emissions (based on 24 hours/year)
NOX, Ib/MW-year
S02, Ib/MW-year
CO2, tons/MW-year
2
0.14
14
487
69.60
20
16
-------
4 Distributed Generation Applications at Data Centers7
DG can be applied in a variety of configurations to meet a hierarchy of facility needs, including
standby/backup power, continuous prime power, and CHP. DG has been successfully employed
in data centers using both fuel cells and other types of prime movers, such as reciprocating
engines, gas turbines, and microturbines. Appendix 1 provides a listing of recent fuel cell
installations in data centers throughout the country. It also includes three case studies of
successful CHP system applications in data centers in New York and California.
4.1 Standby/Backup
The traditional emergency or backup generator is a form of DG. In standby mode, the electric
utility is the primary source of power, and onsite power generation is used only as a backup
during a scheduled shutdown or failure of the utility feed(s). A UPS is used to bridge the time
delay while the standby system starts. This mode of operation is used in more than 99 percent of
network rooms and data centers that have local power generators (see Figure 2) (APC, 2003).
The standard generation technology for this mode is a diesel generator. Emergency diesel
generators are relatively inexpensive; they can pick up load rapidly on start-up, and they are
reliable if properly maintained. Lack of maintenance and testing, however, can reduce system
reliability and lead to the engines failing to start when needed. In addition, diesel generators for
emergency use are very high emitters of pollution and can produce visible smoke, noise, and
odor that can lead to local complaints when a facility tests or is forced to use its generators.
Some data centers are considering a switch to cleaner technologies for backup power, including
gas- or propane-fired engines, microturbines, or fuel cells. These technologies take longer to start
and pick up load than a diesel engine, so they might require additional energy storage in the form
of batteries or flywheels. Fuel-cell-based backup power systems are just emerging as commercial
products. Fuel cell use for backup power is being developed by a number of companies with
remote telecommunications facilities as an early target market. In 2005, a fuel cell product was
introduced into the market that provides backup power to data centers using bottled hydrogen as
a fuel. Another fuel cell product on the market fits within a single 42U Rack and provides 30 kW
of backup power. Fuel cell technology is currently aimed at data center applications where
conventional backup power is impractical and where backup needs are longer than can be
provided by conventional diesel generator-based UPS systems.
4.2 Continuous Prime Power
In continuous prime power mode, DG is the primary source of power, and utility-supplied power
is used primarily as a backup during a scheduled shutdown or failure of the onsite generator. Use
of the utility feed in this way is not free, but most utilities have established standard tariffs for
providing standby power to a customer with its own generator. In some states, these rates are
high enough to discourage customer-sited generation; in other states, standby tariffs are more
7 Information in this section was adapted from APC, 2003.
17
-------
favorable to DG/CHP.8 UPS and battery backup are used to maintain system power during
switchover from onsite to utility power and to maintain power quality. Using DG in continuous
prime power mode without capture and use of waste heat can be cost-effective in areas with high
overall electricity costs and/or high demand charges. One example of a prime power installation
is a 200-kW fuel cell system installed at the Hamilton Sundstrand data center in Windsor Locks,
Connecticut (see Figure 7).
Figure 7. Prime Power Configuration at Hamilton Sundstrand Data Center
Data Center Fuel Cell
Hamilton Sundstrand - A United Technologies Corporation
Source: United Technologies Corporation, 2007
One efficiency measure that works particularly well for continuous prime power integrated with
DG systems is the use of DC power as the underlying power backbone (Robertson, 2003). In a
DC-based system, a dual DC ladder bus aggregates all of the outputs of the distributed generators
and provides multiple paths for the power supply to reach the loads. The system can use any
combination of generators—turbines, natural gas reciprocating engines, diesel engines,
microturbines, fuel cells, or even photovoltaics, operating at any voltage or frequency.
8 The EPA CHP Partnership tracks favorable utility rates (including standby rates) in its regularly updated funding
database at: www.epa.gov/chp/funding.
18
-------
Distribution feeders from the utility can be a source of generation, too. A major advantage of this
architecture—demonstrated through research and development and limited commercial
installation—is the elimination of all paralleling and switching required by traditional alternating
current (AC)-based DG and backup power systems.
4.3 Combined Heat and Power
CHP mode can be configured in the same ways as prime power mode. The difference lies with
the utilization of available heat from the onsite generator to meet facility heating and cooling
loads. As previously stated, data centers require so much power—all of it converted to heat as it
is used within the facility—that the most useful CHP thermal configuration is one that provides
thermally activated air conditioning.
Heat recovered from the onsite power generation unit in the form of steam or hot water can be
utilized in an absorption chiller. High-temperature hot water near or above the boiling point
(under pressure) can power a single-effect absorption chiller. A single-effect absorption chiller
needs about 17,000 Btu of high-temperature hot water or low-pressure steam to produce a ton of
cooling (12,000 Btu). Double effect chillers can produce a ton of cooling with 10,000 Btu of
steam. Absorption chillers would be used in a data center with computer room air handlers, or
less commonly, the chilled water could be fed to water cooled racks. Absorption chillers require
larger cooling tower capacity than standard electric chillers and more pumping power.
Gas turbines, reciprocating engines, high-temperature fuel cells like solid oxide and molten
carbonate, and microturbines are capable of producing steam that can be used in either a single
effect or a double effect chiller. The commercial phosphoric acid fuel cell has a high-temperature
heat recovery option that can produce 250°F hot water for powering a single effect absorption
chiller. PEM fuel cells do not produce temperatures high enough to use in an absorption cycle.
While not a widespread practice at this time, Table 5 shows that there are a number of
commercial CHP installations in dedicated data centers or in office buildings, banks, and
communications facilities where data processing is a major activity within the building. As
shown, a variety of technologies have been used successfully, including fuel cells, reciprocating
engines, gas turbines, and microturbines.
19
-------
Table 5. Combined Heat and Power Installations in Data Center and Communications
Facilities
Facility Name
Telecommunications Facility
Chevron Accounting Center
Guaranty Savings Building
Citibank West FSB Building
QUALCOMM, Inc.
WesCorp Federal Credit Union
ChevronTexaco Corporate
Data Center
Network Appliance Data
Center
Flint Energies Service Center
Facility
Zoot Enterprises
First National Bank of Omaha
AT&T
Continental Insurance Data
Center
Verizon Communications
City
Burlingame
Concord
Fresno
La Jolla
San Diego
San Dimas
San Ramon
Sunnyvale
Warner Robins
Bozeman
Omaha
Basking Ridge
Neptune
Garden City
State
CA
CA
CA
CA
CA
CA
CA
CA
GA
MT
NE
NJ
NJ
NY
Prime Mover
Microturbine
Recip. Engine
Fuel Cell
Microturbine
Gas Turbine
Microturbine
Fuel Cell
Recip. Engine
Fuel Cell
Recip. Engine
Fuel Cell
Recip. Engine
Recip. Engine
Fuel Cell
Capacity
(kW)
120
3,000
600
60
11,450
120
200
825
5
500
800
2,400
450
1,400
Operating
Year
2003
1988
2004
2005
1983/2006
2003
2002
2004
2002
2003
1999
1995
1995
2005
Source: Energy and Environmental Analysis, 2006
4.3.1 Case Studies of Combined Heat and Power Applications at Data
Centers
Following are three case studies of CHP systems successfully in use at data centers in New York
and California.
Example Fuel Cell Application
In April 2002, Verizon Communications was awarded a U.S. Department of Energy (DOE) and
New York State Energy Research and Development Authority (NYSERD A) grant through
programs aimed at supporting distributed energy resources in applications for data processing
and telecommunications. As part of its "Central Office of the Future" project, Verizon installed
multiple fuel cells and reciprocating engine generators to power a large central communications
and data facility in New York (the Garden City project). Verizon configured the fuel cells for
CHP, utilizing waste heat from the fuel cells to provide thermal energy to the site as well. The
company designed the project to increase understanding of controls for multiple DG units and to
utilize low-grade heat for CHP benefits (CNET, 2006).
Verizon's Garden City project is unique because it uses fuel cells as its primary source of energy.
Seven fuel cells generate power for the 292,000-square-foot facility that provides telephone and
data services to roughly 35,000 customers on Long Island. It is connected to the commercial
power grid as backup (CNET, 2006).
Verizon's benefits from the system are:
• $680,000 per year in operating cost savings.
20
-------
• Higher facility reliability.
• Displacement of one-third of its electric air conditioning load to thermally activated
cooling.
• Lower emissions than those produced by central station power—11 million pounds per
year less CC>2 than would have been produced by a fossil-fueled central station power
plant.
• Higher overall efficiency.
These benefits are mitigated somewhat by the current high cost of fuel cell power equipment.
Verizon spent $13 million on the facility, making the payback about 20 years without any type of
incentives. Even with the incentives that Verizon received, the overall system costs, including
capital recovery, are higher than for a conventional system (CNET, 2006).
Example Reciprocating Engine Application
Network Appliance, Inc., an enterprise network storage provider, installed a state-of-the-art CHP
for its facility in Sunnyvale, California (Engle, 2005). Three 275-kW internal combustion engine
packages use natural gas to produce electricity, which is fed to a UPS system that uses flywheels
to provide short-term energy instead of batteries.
The waste heat from the engines is used to produce air conditioning for the data center using
three 120-ton adsorption chillers. The company decided to use adsorption chillers instead of the
more common lithium bromide absorption chillers because the silica gel and water system that
adsorption units are based on makes more effective use of the lower temperature heat available
from the engine jacket water.
The $2.4-million system meets 80 percent of the facility's electricity needs. The capital cost to
Network Appliance was reduced by $800,000 as a result of California's SGIP. Network
Appliance estimates its $1.2-million annual electricity bill for its research and development
building will be cut by two-thirds. Company management first considered developing its own
DG system during the rolling blackouts of 2002, as there was a strong concern that the
company's mission critical power needs could not be adequately met without onsite power
generation.
Example Gas Turbine Application
Qualcomm, a manufacturer and supplier of information technology and communications
equipment, has made numerous energy saving investments at its office/data center world
headquarters in San Diego, California. Some of these improvements have included retrofitting
lighting; upgrading HVAC; improving the building envelope; installing a 500-kW solar
photovoltaic system; using hybrid vehicles for corporate shuttle service; and incorporating
efficient CHP to provide power, cooling, and hot water to the facility. These measures reduced
energy demand by 10 million kWh per year and reduced CO2 emissions by 4,000 tons per year
between 1993 and 2002.
Qualcomm installed a 1.6-MW gas turbine CHP system at its facility in the early 1990s. The
system has saved more than $500,000 annually in cooling costs from two 500-ton absorption
21
-------
chillers driven by heat recovered from the gas turbines. The company saves an additional
$100,000 annually through a heat recovery unit that supplies hot water to the facility. Onsite
electricity generation reduces demand for utility energy by more than 14 million kWh per year,
saving another $122,000. Total annual savings achieved by the CHP system is more than
$775,000. Based on its positive experience with the original gas turbine system, Qualcomm is
currently expanding its campus CHP system, installing two high-efficiency 4.8-MW recuperated
gas turbines with heat recovery. One turbine will be dedicated to a new data center at the
headquarters campus, supplying both power and cooling to the facility.
22
-------
5 Issues Affecting Implementation of Distributed
Generation at Data Centers
Predictions made in the late 1990s that power demand for data centers would grow rapidly to
become a significant share of total U.S. electricity demand have not entirely come true. Power
demand for data centers is increasing in terms of power use per square foot, but overall increases
are occurring at a slower rate. Regionally, however power growth for data centers can be an
important part of overall power demands and growth requirements. Reducing the power
infrastructure requirements of these "data center" centers has become an important consideration
particularly in areas such as the Silicon Valley in the Bay Area of California. Power demands are
continuing to grow while the ability of the local grid to meet existing load plus growth is
becoming increasingly tenuous. In addition, the specter of megawatts of diesel engine capacity
all firing up together during capacity related outages or brownouts might prove to be
unacceptable to many communities.
Fuel cells and other forms of DG power and thermally activated cooling can provide the
reliability and power quality benefits that data centers require while also providing
environmental benefits and energy cost savings. Widespread adoption of such systems in data
center applications has been impacted by a number of issues, however:
• Power outage costs are so high that many facility operators are reluctant to deviate from
the standard design of UPS, battery storage, and standby diesel generators. The failure
modes of these systems are well known, and proper design to ensure reliability has
become standard practice.
• Fuel cells in particular, but also other DG systems, do not have much of a track record in
these high power quality, high reliability applications; therefore, not all failure modes are
completely known. (Specifically, failures from the interaction of the fuel cell or
microturbine system power electronics with the UPS and switching systems are relatively
untested.) Demonstration systems are in place throughout the country, which are
providing important opportunities to prove reliability and improve operational practices.
• Fuel cell DG systems have very high costs. Higher production levels combined with
engineering and materials advances are needed to bring costs down. In addition, not
enough fuel cells have run for an extended duration to provide statistically significant
results to show when stack replacement is necessary, which is a major cost.
• Other types of DG systems are more cost-competitive, but these systems could also
benefit from reductions in packaging, site engineering, and installation costs.
• Part of the value of CHP is the integration of thermally activated cooling from central
chillers, typically used only in large facilities. Some work is needed to demonstrate the
use of chillers in smaller facilities.
• Fuel-cell-based backup power systems are emerging as commercial products. These
small fuel cell systems tend to compete more with battery systems than with diesel
generators.
23
-------
• Battery systems represent a costly component of standard systems in terms of dollars and
in floor space. Integrating DG systems with other forms of energy storage, such as
flywheels, could be an attractive feature for facility operators to consider as a means to
reduce required battery capacity.
For these reasons, continued R&D support and incentives are needed to assist fuel cells and other
forms of DG in becoming more common in data centers.
The EPA CHP Partnership can contribute to the accelerated adoption of DG/CHP in data centers
as follows:
• Provide an information resource to potential users of DG/CHP equipment on available
systems, cost, and performance.
• Provide an information resource to system developers and packagers on the market
opportunity within the data center market.
• Coordinate with ENERGY STAR® to define data center configurations, power, and
cooling requirements today and in the future.
• Support selected data center partners in doing preliminary feasibility studies of DG/CHP
installations
• Quantify user and social benefits of increased reliability, environmental emissions
reductions, and operating cost reductions. These analyses can stimulate the rate of
adoption and also provide a basis for determining appropriate incentive payments.
24
-------
6 References
AFCOM. (2006, March 22). AFCOM's Data Center Institute issues five bold predictions for the
future of the data center industry (press release).
American Internet Services, n.d.(a). The network & facilities—power. Retrieved from
http://www.americanis.net/net data center.php#power.
American Internet Services, n.d.(b). Facility power diagram. Retrieved from
http://www.americanis.net/net data center.php?view=power.
APC. (2003). Alternative power generation technologies for data centers and network rooms.
#64, Revision 1. American Power Conversion.
Bryson, T., Darrow, K., Davidson, K., and Major, B. (2001, April). Advancedmicroturbine
system (AMIS) market study. Prepared for the Department of Energy and Capstone
Turbine Corporation. Onsite Energy Corporation.
CNET. (2006, August 7). Verizon heeds call of fuel cells. CNETNews.com. Retrieved from
http://news.com.com/Verizon+heeds+call+of+fuel+cells/2100-1033 3-6102552.html.
Digital Realty Trust. (2007). Comments submitted regarding April 23, 2007 Public Review
Draft—Report to Congress on Server and Data Center Energy Efficiency Public Law
109-431.
Energy and Environmental Analysis. (2004, January). Distributed generation operational
reliability and availability database. Oak Ridge National Laboratory. Retrieved from
http://www.eea-inc.com/dgchp reports/FinalReportORNLDGREL.pdf
Energy and Environmental Analysis. (2006). Combined heat and power database. Maintained
for the U.S. Department of Energy and Oak Ridge National Laboratory. Retrieved from
http://www.eea-inc.com/chpdata/index.html.
Energy Information Administration, (2006, December), Commercial Building Energy
Consumption Survey: 2003.
Energy Information Administration. (2007, June). Annual energy review 2006. DOE/EIA-
0384(2006). Retrieved from http://www.eia.doe.gov/emeu/aer/diagram5.html.
Engle, D. (2005, July/August). Power sufficiency with 'chilling' efficiency. Distributed Energy
Journal.
Hughes, R. (2005, May). Data centers of the future. Data Center Journal Online. California Data
Center Design Group.
Isom, J. and Paul, R. (2006) The PureCell™ Fuel Cell Powerplant - A Superior Cogeneration
Solution from UTC Power.
Koomey, J.G. (2007, February). Estimating total power consumption by servers in the U.S. and
the world. Lawrence Berkeley National Laboratory.
Lawrence Berkeley National Laboratory [LBNL]. (2003). Cited in Koomey, J. (2004, March).
Data center power use: a review of the historical data. IBM Conference on Energy
Efficient Design, Austin, Texas.
Pouchet, J. (2007). Creating energy efficient data centers. Energy & Power Management.
Robertson, C. (2003, November). Rxfor health care power failures. Distributed Energy, Primen.
United Technologies Corporation. (2007). Application ofPC-25 Fuel Cell at Hamilton
SundstrandData Center, Windsor Locks, CT, picture used with permission.
Ziff-Davis Media/Custom Publishing. (2006). Power Consumption and Cooling in the Data
Center. Retrieved from
http://se.sun.com/promotions/provaserver/pdf/ziff power and cooling it-survey.pdf
25
-------
Table A-l. Fuel Cell Installations in Data Centers and Related Premium Power Applications
Site
NYSERDA
headquarters
The Stella
Group Ltd.
Guaranty
Savings
building
Naval
Oceanic
Center
Ramapo
College
U.S.
Merchant
Marine
Academy
Gabreski Air
National
Guard, base
telephone
exchange
Year
2006
2005
2004
1990s
2000
2002
2004
Capacity
KW
2x5
1 x5
3x200
1 x200
2x200
3x5
4x 1
Manufacturer
Plug Power
Plug Power
UTC Power
UTC Power
UTC Power
Plug Power
ReliOn
City
Albany
Arlington
Fresno
Stennis
Space
Center
Mahwah
Kings Point
Westhamp-
ton
State
NY
VA
CA
MS
NJ
NY
NY
DG Type
Prime
Power
Back-up
CHP
CHP?
CHP
Back-up
Back-up
Comments
Two fuel cells and a photovoltaic (PV) awning system
provide power to the headquarters' systems,
including computer, security and phones. The solar
electric awning will power one-half of NYSERDA's
computer-driven power-load while inverters will
convert 3.6 kW of direct current produced by the
solar modules, into alternating current.
The fuel cell is dedicated to certain circuits within the
office building, providing back-up power and power
quality for the circuits serving the lighting, computers
and office machines (telephone system, security
system, fax and copier). It can also be directed to
charge the battery banks in both the office building
and the adjacent solar home of the Stella Group's
founder.
The building is a 12-story, 100,000-square foot, office
tower, which will house the INS Division of the
Homeland Security Department and the Tax Payer
Advocacy Division of the IRS.
The fuel cells running on natural gas operate in grid
parallel configuration. The project includes a Multi
Unit Load Sharing (MULS) system and static switch
that enables the fuel cells to provide 24/7 power
availability to the building's mission critical loads. The
fuel cells include a UPS for the computer server
rooms on each floor, the communications systems,
building security systems, emergency lighting,
elevator motors, and stairwell ventilation fans.
The fuel cells provide two categories of waste heat.
They provide 1 ,400,000 Btu/hour at 250°F high-grade
heat, and 1 ,400,000 Btu/hour at 1 SOT low-grade
heat. The high-grade heat is piped to a 120-ton
adsorption chiller to supply a cooling load to the
bottom three floors of the building. The return side of
the chiller thermal supply loop supplements the
building's domestic hot water supply. The low-grade
heat is piped to the heating coils associated with
water source heat pumps that have been installed
throughout the building to provide space heating for
offices, hallways, and ground-floor common areas.
The fuel cell is located at the NAVOCEANO
Computer Programming Operations Center (building
1 003) which houses a computer center, library, and
laboratory. The fuel cell thermal output heats hot
water used in the air handlers for space heating and
for reheating cooled air to control humidity.
(Decommissioned 2002.)
Grid parallel. Supplies power and thermal energy (hot
water, space heating) to a student dormitory and a
core academic building complex (housing a computer
center, telephone exchange, and cable TV station).
One-year demonstration of new backup/UPS product.
The fuel cells are connected to the 48-V battery string
on a new uninterruptible power supply (UPS) system
installed for this project. One-year demonstration.
26
-------
Site
Patuxent
Naval Air
Station office
building
Fort Gordon
Army
University of
Technology
Resource
Center
Camp
Roberts
Army
National
Guard Base
Chevron
Data Center
Hamilton
Sunstrand
Data Center
First National
Bank
Year
2004
2004
2005
2002
1997
1999
Capacity
KW
1 x5
1 x5
1 x200
1 x200
1 x200
4x200
Manufacturer
Plug Power
Plug Power
UTC Power
UTC Power
UTC Power
UTC Power
City
Patuxent
River
Fort
Gordon
Paso
Robles
San
Ramon
Windsor
Locks
Omaha
State
MD
GA
CA
CA
CT
NE
DG Type
CHP
Back-up
Prime
Power to
CHP
Prime
Power
Prime
Power
Prime
Power
Comments
Powered nine desktop computers, office lighting, oil
furnace, and life support systems for animals on
display in environmental /conservation building. Grid
connected. Excess power transferred to the grid.
Cogenerated heat used to provide heat to the
building during cold months. (One-year DoD
demonstration.)
Provided back-up to the servers that support the
online virtual training center. U.S. DoD Residential
PEM Fuel Cell Demonstration Program FY 2002.
The facility is the main U.S. Army communications
facility on the west coast that provides worldwide
communications between the U.S. National
Command Authority and deployed military units.
The fuel cell running on natural gas operates in grid
parallel configuration to provide power stabilization
and reduce the facility's electric demand from the
grid. If the project receives additional funding from a
submitted proposal to the California Self Generation
Incentive Program (SGIP), the project will be
expanded to include a grid independent back-up
generation component and CHP capabilities. The
CHP aspect, if implemented, will capture the thermal
energy to be used in conjunction with an absorption
chiller to assist with the cooling loads of the data
center. The fuel cell is equipped with the high-grade
heat option which will provide 400,000 Btu/hour of
250°F heat at its high-grade heat exchanger. This will
allow the fuel cell to support the thermal demand of
an absorption chiller having an output of
approximately 20 to 25 tons of cooling.
Supports critical data and retail transaction systems.
During a power outage, special switching equipment
ensures that the fuel cell will continue to provide
electricity to these systems without interruption.
This plant serves as the primary power source for the
Hamilton Sundstrand Data Center and Data Center
UPSs. It is considered an ultra-high reliable power
source in that if an outage occurs it is backed up by
the grid via transfer switch AND if the grid is
unavailable, the load is transferred to a 500-kW
generator.
Provides the main power for a critical data processing
facility. The bank is one of the largest credit card
processors in the nation. Independent verification of
99.9999% system availability using Probabilistic Risk
Analysis (PRA).
27
-------
Site
New York
Power
Authority,
State Office
of General
Services -
Suffolk
Office
Verizon
Year
2005
2005
Capacity
KW
1 x200
7x200
Manufacturer
UTC Power
UTC Power
City
Hauppage
Garden
City
State
NY
NY
DG Type
CHP
CHP
Comments
The fuel cell is to supply power to the New York State
Regional Emergency Management Office, located in
the facility. The Regional Emergency Management
Office coordinates emergency planning and response
for the New York City and Long Island metropolitan
areas.
The fuel cell running on natural gas is intended to
operate in grid parallel and grid independent modes.
In the event of a utility interruption, the fuel cell will
isolate from the grid parallel circuit and automatically
reconnect to a backup circuit within five seconds.
Upon utility startup, the fuel cell will automatically
return to the grid parallel circuit. The thermal energy
from the fuel cell will be captured and used to
supplement the facility's heat and domestic hot water
system. The hot water loop will have a manual switch
to allow for connection to either the boiler return loop
or the domestic hot water loop depending on
seasonal thermal demands.
Seven fuel cells generate power for a 292,000-
square-foot facility that provides telephone and data
services to some 35,000 customers on Long Island.
The facility is connected to the commercial power
grid as backup. Waste heat is used for heating and
cooling the facility.
Source: Energy and Environmental Analysis, 2006
28
------- |