c/EPA
United
Environmental Protection
Agency New England
One Congress Street, Suite 1100
Boston, MA 02203
FACT SHEET
Dominion Energy Brayton Point, LLC
Closed Cycle Cooling Tower and
Unit 3 Dry Scrubber/Fabric Filter Projects
1 Brayton Point Road
Somerset, MA 02726
EPA Draft Permit Number
052-120-MA13
-------
Dominion Energy Brayton Point, LLC.
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Page 2 of 24
BACT
BTU
CAA
CaO
CEM
CFR
CPA
CO
DS
DEP
EPA
ESA
ESP
FF
FWS
GHG
MM
MMBtu
NAAQS
NMCPA
NSR
NO2
NPDES
PAC
PM2.5
ppm
PSD
PTE
SCR
S02
tpy
IDS
Acronyms and Abbreviations
Best Available Control Technology
British thermal unit
Clean Air Act
Lime reagent
Continuous Emission Monitor
Code of Federal Regulations
Comprehensive Plan Approval
Carbon Monoxide
Dry Scrubber
Massachusetts Department of Environmental Protection
Environmental Protection Agency
Endangered Species Act
Electrostatic Precipitators
Fabric Filter
US Fish and Wildlife Service
Greenhouse Gas
million
Million british thermal units
National Ambient Air Quality Standards
Non-Major Comprehensive Plan Approval
New Source Review
Nitrogen Dioxide
National Pollutant Discharge Elimination System
Powder Activated Carbon
Particulate Matter - 2.5 microns
Particulate Matter - 10 microns
Parts per million
Prevention of Significant Deterioration
Potential to emit
Selective Catalytic Reduction
Sulfur Dioxide
tons per year
Total dissolved solids
-------
Dominion Energy Brayton Point, LLC.
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Page 3 of 24
I GENERAL INFORMATION
Name of Source:
Location:
Applicant's Name and Address:
Application Prepared By:
Draft PSD Permit Number:
EPA Contact:
Dominion Energy Brayton Point, LLC
1 Brayton Point Road,
Somerset, MA 02114
Dominion Energy Brayton Point, LLC
1 Brayton Point Road,
Somerset, MA 02114
Epsilon Associates, Inc.
3 Clock Tower Place, Suite 250
Boston, MA 02114
052-120-MA13
Brendan McCahill
Air Permits, Toxics, and Indoor Programs
Unit (CAP)
(617)918-1652
On August 28, 2008, Dominion Energy Brayton Point, LLC (Dominion) filed a
Prevention of Significant Deterioration (PSD) permit application with the Environmental
Protection Agency Region 1 office (EPA), the "Aug. 2008 PSD application." On January
9, 2009, Dominion filed a supplement to that application to address gaps EPA had
identified in the original submission, the "Jan. 2009 supplemental." A copy of the
application is attached, including the supplement which completed the application.
Dominion proposes to install two natural draft cooling towers at its Brayton Point facility
in Somerset, Massachusetts. The cooling towers are intended to comply with the
requirements of a Federal National Pollutant Discharge Elimination System (NPDES)
permit. In addition, Dominion proposes to install a dry scrubber (DS) control system on
its existing unit # 3 boiler. The dry scrubber is intended to meet the requirements of a
Massachusetts Department of Environment Protection (DEP) regulation for the control of
sulfur dioxide (SO2). Finally, Dominion proposes to install additional Powder Activated
Carbon (PAC) injectors on the Unit #3 boiler to further reduce Mercury (Hg) emissions
from the facility.
EPA proposes to approve Dominion's application and to issue a PSD permit for the
proposed changes to the Brayton Point facility. This document serves as the fact sheet as
-------
Dominion Energy Brayton Point, LLC. Page 4 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
required by 40 CFR part 124-Procedures for Decision Making and explains the legal and
factual basis for EPA's draft permit.
Please note that this project is also subject to the Massachusetts DEP's Comprehensive
Plan Approval (CPA) requirements under the state regulations at 310 Code of
Massachusetts Regulations (CMR) 7.02. The DEP intends to issue a CPA that regulates
all pollutants affected by the proposed project including the pollutants regulated under the
PSD permit.
Dominion must comply with the Federal PSD permit and the DEP's CPA requirements.
However, EPA has worked closely with the DEP to ensure this PSD permit does not
conflict with the DEP's CPA requirements.
II. Project Location
Dominion's Brayton Point facility is located in Somerset, MA about 50 miles south of
Boston and 13 miles east of Providence, R.I. The station is situated east of the Taunton
River, west of the Lee River, north of Mount Hope Bay. The station can be seen south of
US-195 when travelling east just before Fall River.
EPA has designated the southeast portion of Massachusetts including Somerset, MA as
attainment/unclassified for the following national ambient air quality standards
(NAAQS): nitrogen dioxide (NC^), sulfur dioxide (862), carbon monoxide (CO),
particulate matter - 10 microns or less in size (PMio), particulate matter - 2.5 microns or
less in size (PM2.5) and lead. EPA has also designated southeastern Massachusetts as a
moderate non-attainment area under the 8-hour ground level ozone NAAQS.
III. Facility Description
Brayton Point is a 1,600 megawatt fossil-fueled power station. The Station has three coal-
fired units (Units 1-3), and one oil- and natural gas-fired unit (Unit 4). In addition, the
station includes an aboveground fuel oil storage tank farm and associated piping transfer
systems, a coal storage pile and coal handling equipment, a marine fuel receiving terminal, a
wastewater treatment system, active and closed landfills for wastewater treatment system
solids, and electric switching and transmission equipment.
-------
Dominion Energy Brayton Point, LLC. Page 5 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
The proposed natural draft cooling towers project will be located in the northwestern portion
of Brayton Point's facility. The Unit # 3 DS project will be located immediately south of
Unit #3.
IV. Proposed Project
Description of boilers
Brayton point has four electric generating units. Each unit includes a boiler that produces
steam and a steam turbine that generates the electricity. During operation, large draft
fans at each unit take in ambient air and direct into the unit's boiler. The ambient air
mixes with the fuel and then the mixture is burned. The combustion gases are ducted
through emission control equipment and discharged into the atmosphere through stacks.
The wall of each boiler is made up of rows of ducts containing boiler water or feedwater.
The combustion of the fuel heats the feedwater in the boiler to produce steam. The
steam, which is now under high pressure and temperature, is directed to the steam
turbine. The steam turbine is divided into a high-pressure section and a low-pressure
section. The steam from the boiler first enters and expands into the high-pressure turbine
section. After the steam exists from the high-pressure turbine, it flows back to the
reheater section of the boiler where the temperature of the steam is raised again. The
reheated steam then enters and expands into the low-pressure turbine section. The
exhaust steam from the low-pressure turbine now enters the condensers. Cooling water
from the bay condenses the exhaust steam back into water. The cooled water is pumped
back to the boilers completing the cycle of powering the turbines.
Brayton Point requires large amounts of cooling water to operate the condensers. The
facility currently draws its cooling water from the Mount Hope Bay. The water is pumped
to the condensers, cools the steam back into water, and returns to Mount Hope Bay.
However, this "once through" cooling system meant that large amounts of now heated
cooling water is returned directly to the Bay with adverse affects to the Bay's ecosystem.
In place of the once through cooling system, Dominion will now install and operate a
"closed loop" cooling system. Dominion will now pump the warm water leaving the
condensers to two new large natural draft cooling towers. The water will be allowed to
cascade down into a water collection system. Cool outside air entering from below the
towers mixes and cools the water as it cascades down. The now cooled water is then
pumped back to the condensers.
-------
Dominion Energy Brayton Point, LLC. Page 6 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Cooling Towers
Dominion plans to build and operate the natural draft cooling tower(s) on an approximately
ten-acre portion of the northwest corner of the facility. The tower(s) will be approximately
500 feet tall, and approximately 220 feet diameter at the exhaust exit. Each tower has a
maximum water circulation rate of approximately 400,000 gallons per minute.
To support the towers, Dominion will install new water storage basins, relocate an existing
wastewater treatment system, and install new piping to convey the cooling water to and
from the new cooling towers.
During the mixing of the air and cooling water, a very small fraction of the water will exit
the towers as drift droplets. Those drift droplets will contain dissolved solids (e.g., salts),
which could become PlVt.s or PMio emissions when the water evaporates.
Dry Scrubber
To comply with state requirements for the control of SC>2 emissions, Dominion proposes to
install a DS/Fabric Filter (FF) control system. The DS/FF systems are widely used in the
coal-fired power plant industry to reduce SC>2 emissions from the combustion of coal.
Dominion will install the DS/FF system on the Unit #3 boiler.
The DS system removes 862 from the flue gas using a lime reagent (CaO). The lime
reagent is injected into the flue gas as a fine mist. The reagent then reacts with the SC>2
following these chemical reactions:
Ca(OH)2 + SO2 => CaSO3 • Y2WO + 1/2H2O (dominant reaction)
CaSO3 • V2H2O + V2O2 + l^ffiO => CaSO4 • 2H2O (minimal CaSO3 available)
The treated flue gas is ducted to the FF where the dry reaction byproducts are captured and
removed from the flue gas. These byproducts include unreacted calcium hydroxide, calcium
sulfite, calcium sulfate, lime grit, and fly ash. Dominion proposes to recycle a portion of the
solids back to the DS system. The recycled solids contain un-reacted CaO that can remove
additional SC>2 from the flue gas. Dominion will then duct the scrubbed flue gas through the
existing Unit No. 3 stack and into the atmosphere.
In addition to the 862 emission control system, Dominion is proposing to increase the
efficiency of its mercury removal systems. Dominion currently uses a powder activated
-------
Dominion Energy Brayton Point, LLC. Page 7 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
carbon (PAC) injection system to reduce Hg emissions from the combustion of coal. The
gas phase mercury in the flue gas contacts and attaches to the surface of the PAC. The PAC
is then collected by an electrostatic precipitator (ESP) which is particulate control device.
Dominion currently injects PAC upstream of the existing ESP on Unit #3. Dominion
proposes to install the additional PAC injection point upstream of the proposed DS/FF.
Once completed, Dominion expects this new PAC injection point to become the primary
injection point for Unit #3.
V. Current Permits
Dominion's Brayton Point facility is currently not subject to any state or Federal PSD or
nonattainment NSR permit for major sources.
VI. PSD Review
As mentioned, EPA has classified eastern Massachusetts a moderate nonattainment area
for ground level ozone and attainment for all other criteria pollutants. The classifications
are located in 40 CFR 81.322.
Before March 2003, EPA delegated the Federal PSD program at 40 CFR 52.21 to the
Massachusetts DEP. Under the terms of the delegation agreement, the DEP issued PSD
permits to sources in Massachusetts. However, in March 2003, Massachusetts returned
the PSD program to EPA. Since this time, EPA has issued PSD permits in
Massachusetts. The DEP continues to administer its state permitting regulations and
issue CPAs to sources in Massachusetts. Typically, sources that are subject to the
Federal PSD program are also subject to the state permitting program.
The PSD regulations require major new stationary sources or major modifications to an
existing major stationary source to undergo a PSD review and to receive a PSD permit
before commencing construction.
40 CFR 52.21 (b) (1) of the Federal PSD regulations defines a major stationary source as
any 28 designated stationary source categories with potential emissions of 100 tons per
year or more of any criteria pollutant, or any other stationary source with potential
emissions of 250 tons per year or more of any criteria pollutant.
40 CFR 52.21 (b)(2) defines a major modification as "any physical change in or change
in method of operation of a major stationary source that would result in: a significant
-------
Dominion Energy Brayton Point, LLC. Page 8 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
emissions increase of a regulated NSR pollutant; and a significant net emissions increase
of that pollutant from the major stationary source."
40 CFR 52.21(b)(23) defines the "significant" emission rate for the each regulated NSR
pollutant.
If the permitting authority determines that a new stationary source or new modification is
subject to the PSD program, the source must apply for and obtain a PSD permit that
meets regulatory requirements including:
• Best Available Control Technology (BACT) that requires sources to minimize
emissions to the greatest extent possible;
• An ambient air quality analysis to ensure that all the emission increases do not cause
or contribute to a violation of any applicable PSD increment or NAAQS;
• An additional impact analysis to determine the direct and indirect effects of the
proposed source on industrial growth in the area, soil, vegetation and visibility; and
• Public comment including an opportunity for a public hearing.
VII. PSD Applicability
Overview
To determine if the proposed projects are subject to PSD review, Dominion first
determined if the existing Brayton Point facility is a major stationary source. Brayton
Point is a fossil fuel power plant with a heat input of over 250 million British Thermal
Units per Hour (MMBtu/hr). Fossil-fuel fired facilities with heat inputs greater than 250
MMBtu/hr are one of the 28 designated source categories listed in the Federal definition
for major stationary source. If Brayton Point's PTE exceeds 100 tpy, it meets the
definition of "major stationary source" under the federal PSD program. Potential
emissions or PTE as defined in 40 CCR 52.21(b)(4) is the maximum capacity of a
stationary source to emit a pollutant under its physical and operational design. Recent
emission estimates for Brayton Point show that its PTE well exceeds the 100 tpy
threshold level for all the criteria pollutants. See e.g. Table 2-2 in sec. 2-4 Jan 2009 supp.
Therefore, the Brayton Point facility is a major stationary source.
The Dominion application contains two concurrent but separate and severable projects:
the natural draft cooling towers and the DS/FF SCh system. Dominion is also installing
additional PAC injectors for the control of Hg emissions upstream of the new FF. If the
combined net emission increase from a project exceeds the PSD program's significance
-------
Dominion Energy Brayton Point, LLC. Page 9 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
levels for any
pollutant, the project is a major modification and subject to the PSD program
requirements.
EPA relied on Dominion's application to determine the net emission increase from each
project. Dominion followed the procedures in 40 CFR 52.21(a)(2)(iv)(/): "Hybrid test
for projects that involve multiple types of emission units." The actual-to-potential test in
40 CFR 52.21(a)(2)(iv)( d) is applied to the cooling tower project, and the actual-to-
projected-actual test in 50 CFR 52.21(a)(2))(iv)( c) is applied to the Unit 3 DS/FF
project.
Projected Emission Increase: Cooling Towers
Dominion followed the applicability procedures in 52.21(a)(2)(iv)(d) "actual-to-potential
test for projects that only involve the construction of a new emission(s) unit" to determine
the emission increase from the cooling towers. Dominion determined the difference
between the potential emissions or potential to emit (PTE) of the cooling towers as
defined in (b)(4) of this section and the baseline actual emissions as defined in (b)(48)(iii)
for the cooling towers. Baseline actual emissions are the actual emissions from an
emission unit before a physical or operational change and means "the average rate, in
tons per year, at which the unit actually emitted the pollutant during any consecutive 24-
month period selected by the owner or operator within the 5-year period immediately
preceding" the operational change. 40 CFR 52.21(b)(48)(i). Since these are new
emission units, the actual emission baseline for the cooling towers is zero. Potential
emissions or PTE is defined as the maximum capacity of a stationary source to emit a
pollutant under its physical and operational design. Dominion used EPA's AP-42
emission factors and emission guidance documents to calculate the PTE for the cooling
towers. Table 1 provides the results of the actual-to-potential emission calculations for
the cooling towers.
-------
Dominion Energy Brayton Point, LLC.
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Page 10 of 24
Table 1
Cooling towers: Actual-to-Potential applicability test
Pollutant
Carbon Monoxide
Nitrogen oxides
Sulfur dioxide
Volatile organic compounds
Filterable PM
Filterable PM10
Filterable PM2.5
Total PM
Total PM10
Total PM2.5
Lead
Fluorides
Sulfuric Acid Mist
Hydrogen sulfide, total reduced
sulfur, Reduced sulfur
compounds
Other NSR Pollutant
Baseline Actual
Emissions
0
0
0
0
0
0
0
0
0
0
0.0
0
0
0
0
Projected Actual
Emissions
None expected
None expected
None expected
None expected*
389
389
389
389
389
389
None expected
None expected
None expected
None expected
None expected
Emissions
Increase
None expectec
None expected
None expectec
None expected*
389
389
389
389
389
389
None expected
None expectec
None expected
None expectec
None expected
* some small amount of VOC could be emitted from stripping naturally-occurring
volatile organics from the circulating water.
In calculating the emission increase from the cooling towers, Dominion is required to
include emission increases from the facility's boilers if the cooling towers would allow
the boilers to increase operations. However, Dominion and staff from EPA Region 1's
NPDES program note that the existing once-through cooling system does not restrict the
facility's current operations. Therefore, the proposal to install the cooling tower as part
of a closed-loop cooling system will not increase operations or increase emissions from
the facility's boilers.
10
-------
Dominion Energy Brayton Point, LLC. Page 11 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Projected emission increase: DS/FF Project
As previously described, the DS/FF project is a physical change to the Unit #3 boiler at
Brayton Point. Dominion applied the 52.21(a)(2)(iv)(c) "actual-to-projected-actual
applicability test for projects that only involve existing emission unit(s)" to determine the
emission increase from the DS/FF project. Dominion calculated the difference between
the "baseline actual emissions" from the Unit 3 boiler before the installation of the DS/FF
and the "projected actual emissions" that the Unit #3 after the DS/FF is installed. 40 CFR
52.21(b)(41)and(48).
As previously described, baseline actual emissions are the actual emissions from an
electric utility steam generating unit before a physical or operational change and meaning
the average rate, in tons per year, at which the unit actually emitted the pollutant during
any consecutive 24-month period selected by the owner or operator within the 5-year
period immediately preceding the operational change. 40 CFR 52.21(b)(48)(i). The
regulations also allow PSD permit applicants to select different 24-month periods for
different pollutants depending on operations from the facility. Dominion used the actual
emissions selected from January 2003 through December 2004 for NOx and 862, and
January 2006 through December 2007 for all other pollutants to determine baseline actual
emissions.
The projected actual emission rate is the maximum annual rate, in tons per year, at which
an existing emissions unit is projected to emit a regulated NSR pollutant in any one of the
10 years (12-month period) following the date the unit resumes regular operation after the
project. In determining the projected actual emissions, the owner or operator of the
source must consider all relevant information, including but not limited to historical
operational data, the company's expected business activity, and the company's highest
projections of business activity. 40 CFR 52.21(b)(41). Dominion stated that its emission
projections rely on historical data, company projections, and compliance plans under the
Massachusetts 7.29 Emission Control Plan Regulations. Dominion noted that reductions
in SC>2, fluorides, and sulfuric acid mist are based on reductions from the installation of
the DS. Reductions in NOx are based on projections for operation using the previously
permitted and installed selective catalytic reduction system. In addition, Dominion does
not believe that the DS/FF project will create any incentives or remove any barriers that
would cause an increase in the utilization rate on unit #3. Therefore, in accordance to 40
CFR 52.21(b)(41)(ii)(c), Dominion excluded from its projections the increased utilization
due to product (electricity) demand growth. Table 2 contains the results of the projected
actual emissions calculations for the DS/FF project.
11
-------
Dominion Energy Brayton Point, LLC.
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Page 12 of 24
Table 2
DS/FF Projected Actual Emissions Calculation Results
Pollutant
Carbon Monoxide
Nitrogen oxides
Sulfur dioxide
Volatile organic compounds
Filterable PM
Filterable PM 10
Filterable PM2.5
Total PM
Total PM 10
Total PM2.5
Lead
Fluorides
Sulfuric Acid Mist
Hydrogen sulfide, total
reduced sulfur, Reduced
sulfur compounds
Other NSR Pollutant
Baseline Actual
Emissions
1,268
6,167
16,294
50.4
134
134
134
670
670
670
0.0
111
78
none expected
none expected
Projected Actual
Emissions
1,268
1,300
1,485
50.9
186
186
186
464
464
464
0.0
78
55
none expected
none expected
Emissions Increase
0
-4,867
-14,809
0.5
52
52
52
-206
-206
-206
0.0
-33
-23
None expected
None expected
12
-------
Dominion Energy Brayton Point, LLC.
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Page 13 of 24
Table 3 provides the total emission increase for the two projects
Table 3.
Total Emissions Increase for the Cooling Tower and DS/FF Projects
Pollutant
Carbon Monoxide
Nitrogen oxides
Sulfur dioxide
Volatile organic compounds
Filterable PM
Filterable PM 10
Filterable PM2.5
Total PM
Total PM 10
Total PM2.5
Lead
Fluorides
Sulfuric Acid Mist
Hydrogen sulfide, total
reduced sulfur, Reduced
sulfur compounds
Other NSR Pollutant
Baseline Actual
Emissions
1,268
6,167
16,294
50
134
134
134
670
670
670
0.0
111
78
None expected
None expected
Projected Actual
Emissions
1,268
1,300
1,485
50.5
575
575
575
853
853
853
0.0
78
55
None expected
None expected
Emissions Increase
0
-4,867
-14,809
0.5
441
441
441
183
183
183
0.0
-33
-23
None expected
None expected
The table shows that the two projects result in a significant emission increase for total and
filterable-only PMio and PM 2.5 emissions and are subject to PSD program review for those
pollutants. EPA has reviewed Dominion's emissions information and concurs with
Dominion's findings.
VIII. PSD Program Requirements
The PSD program requires the applicant to demonstrate that the natural draft cooling
towers and DS and PAC systems will incorporate air pollution control technologies
representative of BACT, and that the resulting emissions will not cause or contribute to a
violation of applicable ambient air quality standards or PSD allowable increments. The
applicant is also required to assess the project's impacts on soils, visibility and secondary
growth.
13
-------
Dominion Energy Bray ton Point, LLC. Page 14 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
The complete list of applicable Federal PSD program regulations is shown below:
1. 40 CFR 52.21(j) Control Technology Review (Best Available Control Technology)
2. 40 CFR 52.2l(k) Source Impact Analysis (Air Quality Impact Assessment)
3. 40 CFR 52.21(1) Air Quality Models
4. 40 CFR 52.2l(m) Air Quality Analysis
5. 40 CFR 52.2l(n) Source information
6. 40 CFR 52.2l(o) Additional Impact Analysis
7. 40 CFR 52.21(p) Federal Class I Area Impacts (Air Quality Impact Assessment)
IX. BACT
As required by the Federal PSD program at 40 CFR 52.21(j)(2) and (3), Dominion is
required to apply BACT to the PMio and PM2.5 emission increase from the cooling towers
and DS and PAC systems. BACT is defined as, an emissions limitation... based on the
maximum degree of reduction for each pollutant subject to regulation under [the Clean
Air] Act which would be emitted from any proposed major stationary source or major
modification which the Administrator, on a case-by-case basis, taking into account
energy, environmental, and economic impacts and other costs, determines is achievable
for such source or modification through application of production processes or available
methods, systems and techniques... for control of such pollutant. 40 CFR 52.21(b)(12);
Clean Air Act (CAA) 169(3).
In making its BACT determination, EPA follows the five step "top-down" methodology
for determining BACT:
i. Identify all control technologies. Identify all potentially available control options,
including inherently lower emitting processes and practices, add-on control
equipment, or combination of inherently lower emitting processes and practices and
add-on control equipment.
2. Eliminate technically infeasible options. Eliminate technically infeasible options
based on physical, chemical, or engineering principles.
3. Rank remaining control technologies by control effectiveness. Rank the remaining
control options by control effectiveness (i.e., expected emission reduction).
4. Evaluate most effective controls and document results. Determine the economic,
energy, and environmental impacts of each option on a case-by-case basis. Eliminate
options that are not achievable considering these impacts.
14
-------
Dominion Energy Bray ton Point, LLC. Page 15 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
5. Select the BACT. Select the highest-ranked (most effective) option not eliminated as
BACT and develop an emissions limitation based on the selected option.
Dominion BACT Analysis
Dominion provided a BACT analysis in Section 4 of the August 2008 PSD application
which was enhanced in the January 2009 supplemental. Dominion conducted a separate
BACT analysis for PM emission emitted from the cooling tower and the DS system. The
two analyses concluded that:
• BACT for the cooling towers is drift eliminators with a 0.0005% drift rate; and
• BACT for the Unit #3 boiler is the use of fabric filter with felted bags achieving a
total PMio/PM2.5 emission rate of 0.025 Ibs/MMBtu and a filterable-only
PMio/PM2.5 emission rate of 0.010 Ibs/MMBtu.
The following provides a summary of the BACT analyses.
Cooling Tower
As mentioned previously, the PM emissions emitted from the cooling towers result from
a portion of the cooling water becoming entrained in the air stream and carried out of the
tower as "drift" droplets. The paniculate matter in the drift droplets are then classified as
PM emissions.
In its analysis, Dominion reviewed the following control options:
• Air Cooled Condensers
• Once-Through Cooling (existing configuration)
• Fresh Water
• Mechanical Draft Cooling Towers.
• Reduction in Cycles of Concentration.
• Reduction in Air Velocity
• Drift Eliminators
15
-------
Dominion Energy Bray ton Point, LLC. Page 16 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Dominion determined that the following options are technically infeasible:
* Once-Through Cooling. Brayton Point Station currently uses once-through cooling
to reject the heat into the waters of Mount Hope Bay. The Station is under EPA and
DEP Orders to discontinue once-through cooling. The use of once-through cooling is
technically infeasible because it would violate the Orders.
* Fresh Water. The use of water with lower solids content would reduce particulate
emissions from the cooling towers. There is, however, no adequate supply of fresh
water available. Historically, Brayton Point used some fresh water obtained from the
Town of Somerset. However, this was discontinued to allow more fresh water use
for Somerset residents. The quantities of fresh water needed to provide cooling to the
station (up to 70 million gallons per day) exceed the volume that could be legally
withdrawn from any nearby freshwater source. This technical difficulty precludes
the successful use of fresh water as a control option.
* Reduction in Cycles of Concentration. Dominion intends to maintain
approximately 1.5 cycles of concentration in the cooling tower circulating water.
Reducing the cycles of concentration would reduce the salinity in the circulating
water, which would in turn reduce particulate emissions. However, Dominion
maintains that decreasing the cycles of concentration would increase the total water
discharge into from Mount Hope Bay. The increase water discharge would increase
the thermal discharge to Mount Hope Bay above what is allowed in Brayton Point
Station's NPDES permit.
Dominion then rated and evaluated the remaining control options.
Air-cooled condensers: As the name suggests, air-cooled condensers use air to cool the
steam in the boiler. The technology would essentially replace the current water-cooled
condensers. The technology would replace the need for any water from Mount Hope Bay.
The technology would also eliminate any drift that results in PM emissions. However,
Dominion eliminated the option based on its higher installation cost and energy usage
and the likelihood that the additional land area needed for air-cooled condensers would
simply not be available or would lead to unacceptable wetlands impacts.
Mechanical-draft cooling towers: Mechanical-draft cooling towers use large rotating
blades to draw air into the cooling towers versus a natural draft set up by the size and
configuration of towers. The towers would also use drift eliminators similar to the
proposed towers. Dominion excluded the option based on its higher installation and
operational cost with no significant difference in total PM emissions.
16
-------
Dominion Energy Bray ton Point, LLC. Page 17 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Reduction in air velocity: Reducing the velocity of the air mixing with the cooling water
would reduce droplet formation and PM emissions. However, the method to reduce air
velocity while maintaining proper water cooling is the construction of larger cooling
towers. Dominion excluded the larger towers based on higher cost and greater visibility
impacts, while only providing marginal reductions in PM emissions.
Drift Eliminators: Drift eliminators are installed above the area where the air mixes with
the cooling water. They create a long "tortuous" path for the air to pass through. This
longer path allows the water droplets to lose velocity and to fall back into the tower. In
general, efficiency increases with greater depth of the eliminators resulting in a longer
tortuous path. However, increasing the depth of the eliminators produces increased "back
pressure," that is, the pressure required to push the air through the eliminators. After a
certain depth, the towers would not produce enough upward draft to overcome the back
pressure. Dominion's analysis concluded that a drift rate lower than 0.0005% is not
practical.
In summary, Dominion's proposed BACT for the natural draft cooling towers is drift
eliminators achieving a drift rate of 0.0005%. The drift rate is based on vendor
guarantees and recent BACT determinations made on mechanical draft cooling towers
controlled using drift eliminators.
The drift eliminator's drift rate and emission limits will apply at all times while the
cooling towers are in operation.
EPA reviewed Dominion's analysis and agrees with its results. Therefore, EPA's
proposed BACT for the natural draft cooling towers is drift eliminators achieving a drift
rate of 0.0005%. In addition, EPA will limit the total PM2.5 and PMio emissions from
each cooling tower to the following:
• 24-hour average - 1066 pounds
Finally, to ensure compliance with the daily and yearly cooling tower emission rates,
EPA proposes to limit the total dissolved solids in the circulating water flow and
blowdown to 52,250 parts per million by weight.
17
-------
Dominion Energy Bray ton Point, LLC. Page 18 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
EPA's BACT decisions for the cooling towers are based on section 4 of Dominion's
August 2008 PSD application, the BACT analysis contained in January 2009
supplemental, and EPA's expertise.
Unit #3 Dry Scrubber/Fabric Filter
As previously described, Dominion is proposing to install two control systems, the DS
and additional PAC injectors, onto the existing Unit #3 boiler itself. Both control
systems inject materials into the flue gas that could increase the total PM emissions from
the unit #3 boiler.
Dominion's analysis reviewed the following particulate matter control options:
• Fabric filter, specifically two varieties:
o with felted bags
o with coated bags
• Electrostatic precipitator, specifically three varieties:
o Wet electrostatic precipitator
o Dry electrostatic precipitator
o Membrane wet electrostatic precipitator
• Fabric filter with wet electrostatic precipitator in series
• Electrostatic fabric filter
• Electro-catalytic oxidation
• Wet scrubber
• Cyclone or multiclone collector
• Side stream separator
18
-------
Dominion Energy Bray ton Point, LLC. Page 19 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
Dominion's analysis did not consider options to reduce PM emissions through the use of
combustion control. The analysis concluded that the PM emission increase resulted from
the operation of the DS system and PAC injectors and not due to any physical or
operational change to the unit #3 boiler itself. EPA proposes that a BACT decision that
requires the installation of state-of-the-art add-on controls represents BACT for the Unit
#3 boiler.
The analysis found that the following options were technically infeasible:
* Membrane wet electrostatic precipitator. This is an emerging technology that is
not demonstrated-in-practice for this application. Ohio University researchers have
performed industrial-scale tests of a wet electrostatic precipitator that uses
polypropylene membranes instead of metal to reduce corrosion and improve long-
term performance. No utility-scale demonstrations have been performed and the
performance for PM2.5 control has not been evaluated.
* Electrostatic fabric filter. This is an emerging technology that is not demonstrated-
in-practice for this application. The use of a combination of electrostatic
precipitation and fabric filtration has been tested on a cyclone boiler firing
subbituminous coal1, and similar technology is being marketed by GE Energy2. The
lack of operating experience would add significant uncertainty to the air pollution
retrofit project, as would the need to coordinate its installation and operation with the
dry scrubber. Also, it is not clear that this technology would provide any emissions
reduction beyond the proposed case.
* Electro-catalytic oxidation. This is an emerging technology that is not
demonstrated-in-practice for this application. Powerspan Corporation describes the
Electro-Catalytic Oxidation (ECO) process as a multi-pollutant control system
consisting of an oxidation reactor followed by an absorber and wet electrostatic
precipitator. A demonstration project was conducted on a slipstream of an Ohio coal
boiler, funded in part by the Ohio Coal Development Office and the Ohio Air Quality
Development Authority. Dominion does not consider this emerging technology an
acceptable alternative to the proposed dry scrubber for SO2 control, and it offers no
apparent advantages over traditional wet ESPs for particulate control. The technical
challenges associated with scale-up of this emerging technology are significant.
1 "Demonstration of a Full-Scale Retrofit of the Advanced Hybrid Particulate Collector Technology"
(DOE/NETL-2007/1255, February 2007).
2 http://www.gepower.com/prod serv/products/particulatematter/en/max9/index.htm
19
-------
Dominion Energy Brayton Point, LLC. Page 20 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
The analysis then ranked the remaining technologies according to their control efficiency.
The two options with the highest efficiencies were FF using felted bags in series with wet
ESP and FF using felted bags operating alone. Dominion excluded FF installed with a
wet ESP system from further review based on the significantly higher incremental costs
associated with the installation of a wet ESP.
In summary, Dominion's proposed BACT for the Unit #3 boiler installed with a DS and
additional PAC injectors is a FF using felted bags achieving the following emission rates:
Total PM 10 emissions: 0.025 Ibs/MMBtu (141.4 Ibs/Hr)
Total PM 2.5emissions: 0.025 Ibs/MMBtu (141.4 Ibs/Hr)
Filterable PM 10 emissions: 0.010 Ibs/MMBtu (56.6 Lbs/Hr)
Filterable PM 2.5emissions: 0.010 Ibs/MMBtu (56.6 Lbs/Hr)
The BACT emission limits apply at all times while the unit #3 boiler is operating.
EPA has reviewed Dominion's analysis and agrees with its results. Therefore, EPA's
proposed BACT for the Unit #3 boiler installed with a DS and additional PAC injectors is
a FF using felted bags achieving the following emission rates:
Total PM 10 emissions: 0.025 Ibs/MMBtu (141.4 Ibs/Hr)
Total PM 2.5emissions: 0.025 Ibs/MMBtu (141.4 Ibs/Hr)
Filterable PM 10 emissions: 0.010 Ibs/MMBtu (56.6 Lbs/Hr)
Filterable PM 2.5emissions: 0.010 Ibs/MMBtu (56.6 Lbs/Hr)
EPA required Dominion to express BACT in terms of filterable-only PM emission limits
and total PM (i.e., filterable and condensable) emission limits. The filterable-only PM
emission limits provide a more accurate estimate on the performance of the FF. The total
PM emission limits ensure that the ambient air quality impacts from the boiler are
evaluated and meet all federal air quality standards. Both the total and filterable PM
BACT emission rates are based on vender guarantees and recent BACT determinations
for similar sources.
EPA's BACT decision for Unit #3 is based on a review of the information provided in
section 4 of Dominion's August 2008 PSD application, the BACT analysis contained in
January 2009 supplemental, and EPA's expertise.
20
-------
Dominion Energy Brayton Point, LLC. Page 21 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
X. Monitoring
Cooling Towers:
The proposed B ACT drift rate for the drift eliminators was determined by the drift
eliminator vendor using a small scale laboratory testing method that is the testing
standard for the industry. EPA does not know of a large scale test method that can be
used to accurately measure the efficiency of drift eliminators installed in large structures
like the control towers proposed by Dominion.
As an alternative, EPA is proposing to require Dominion to calculate the drift eliminator
dimensions needed to meet the 0.0005% drift rate using the industry standard testing
methodology and to provide this information to EPA before commencing construction.
In addition, to show compliance with the cooling tower's 24-hour PM emission rate, EPA
is proposing that Dominion continuously monitor the following parameters:
• gallons per minute circulating water flow;
• drift rate; and
• solids concentration in the circulating water flow or blowdown.
EPA proposes to monitor the gallons per minute of circulating water through the use of
pump output curves. Dominion will establish these curves using curves supplied by the
pump manufacturer or by determining the amount of water flow for a given pump output
rate. Once the curves are established, pump output rates can directly correlated to gallons
of water circulating. This is a widely accepted methodology used in EPA's NPDES
permits.
The drift rate will be based on the BACT drift rate selected for the drift eliminators and
will be monitored using bench testing information provided by the vendor.
EPA proposes to quantify the total dissolved solids (TDS) using a conductivity monitor.
Conductivity is a measure of water's ability to conduct an electric current. Electrical
conductivity of water is based on the concentration of dissolved salts in the water. Since
electrical conductivity is directly proportional to the concentration of dissolved salts,
monitoring electrical conductivity can monitor the salt concentration or the total
dissolved salts circulating in the cooling towers.
21
-------
Dominion Energy Brayton Point, LLC. Page 22 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
To ensure the drift eliminators and cooling towers are properly maintained, EPA is also
proposing to require Dominion to inspect the equipment on a quarterly and yearly
schedule.
DS/FF System:
EPA proposes to determine initial compliance of the BACT emission limits using EPA
test methods 40 CFR Part 51, Appendix M, Method 201 or 201A and Method 202. The
date for completing the initial compliance date is longer in this PSD permit than what 40
CFR Part 60, Subpart Da requires for a coal-fired electric generating unit under EPA's
New Source Performance Standards (NSPS). (Note that the addition of this pollution
control equipment does not trigger the modification provisions of the NSPS.) Under the
NSPS, new, modified, or reconstructed emission units, including electric generating
units, must perform the initial compliance test no later than 180 days from achieving
maximum production rate. This PSD permit allows Dominion a longer time to complete
the initial compliance test. The longer time, allows Dominion to work through new
equipment issues, is triggered when Dominion accepts ownership of the new pollution
control equipment pursuant to the contract(s) with its vendor(s). However, in the event of
a long contractual dispute, Dominion must complete the initial compliance test no later
than 12 months from commencing startup of the DS/FF (since unit #3 is an existing unit,
it is capable of maximum production regardless of whether the DS/FF can meet its
maximum capacity).
The basis for the longer time is due to the several factors unique to the DS/FF project for
unit #3. The DS/FF is a retrofit project at an existing emission unit which sometimes can
cause unexpected delays during the shakedown period. With similar retrofits at other
coal-fired electric generating emission units, Dominion has experienced significant
delays with its vendors in meeting their contractual obligations, especially being able to
meet the emission limits required by the contract. Similar issues with other new pollution
control equipment have caused delays of almost 6 months before Dominion can take
ownership of the pollution control equipment from its vendors. If similar issues arise
during the installation process of the DS/FF on unit #3, a compliance test conducted
within 180 days from initial startup may not be representative of future PMio and PM2.5
emissions. Therefore, EPA is allowing Dominion for a longer time to conduct the initial
compliance test than Agency has had in other PSD permits issued to sources within
Massachusetts.
22
-------
Dominion Energy Brayton Point, LLC. Page 23 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
In addition, to determine on-going compliance with the BACT emission limits, EPA shall
require Dominion to continuously monitor the following parameters:
• daily usage of lime reagent injected by the DS;
• daily usage of PAC used in the PAC injectors; and
• pressure drop across the FF.
In addition, EPA shall require Dominion to monitor the hourly heat input rate for unit #3
using 40 CFRPart 75 compliance requirements.
XI. Source Impact Analysis
Please refer to Attachment I, memo from Brian Hennessey to Brendan McCahill dated
January 22, 2009. For modeling impacts due to this permitting action, the emissions
from the two projects were combined.
XII. Additional Impact Analysis
Please refer to Attachment I, memo from Brian Hennessey to Brendan McCahill dated
January 22, 2009. For modeling impacts due to this permitting action, the emissions
from the two projects were combined.
XIII. Endangered Species Act (ESA)
Section 7 of the ESA requires that certain federal actions such as federal PSD permits
address the protection of endangered species in accordance with the ESA.
Please refer to Attachment II, Draft Memo from Donald Dahl to the Record, which
explains EPA's analysis to date concerning the Agency's compliance with the ESA.
XIV. Environmental Justice
EPA also considered whether the facility's emissions would have disproportionately high
and adverse human health or environmental effects on minority or low-income
populations. See Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations, Executive Order 12,898, 59 Fed. Reg. 7,629
(Feb. 16, 1994). Because the facility's emissions will not result in exceedance of either
the NAAQS or a PSD increment, EPA concludes that the facility will not have
23
-------
Dominion Energy Brayton Point, LLC. Page 24 of 24
Prevention of Significant Deterioration Permit
Draft PSD Permit number 052-120-MA13
disproportionately high and adverse human health or environmental effects on minority
or low-income populations.
XV. Comment Period, Hearing and Procedures for Final Decisions
All persons, including applicants, who believe any condition of the Draft Permit is
inappropriate must raise all issues and submit all available arguments and all supporting
material for their arguments in full by the close of the public comment period, to Brendan
McCahill, U.S. Environmental Protection Agency, Office of Ecosystem Protection, Air
Permits, Toxics and Indoor Air Programs, 1 Congress Street, Suite 1100, Attn. CAP,
Boston, MA 02114-2023.
A public hearing will be held on the date stated in the public notice. In reaching a final
decision of the Draft Permit, EPA will respond to all significant comments and make
these responses available to the public at EPA's Boston office.
Following the close of the public comment period, and after the public hearing, the EPA
will issue a Final Permit decision and forward a copy of the final decision to the applicant
and each person who has submitted written comments or requested notice. Within 30
days following the notice of the permit decision, any interested parties may submit a
petition for review of the permit to EPA's Environmental Appeals Board consistent with
40C.F.R. § 124.19.
XVI. EPA Contacts
Additional information concerning the draft permit may be obtained between the hours of 9:00
a.m. and 5:00 p.m., Monday through Friday, excluding holidays from:
Brendan McCahill
Office of Ecosystem Protection
U.S. Environmental Protection Agency
1 Congress Street, Suite 1100 (CAP)
Boston MA 02114-2023
Telephone: (617) 918-1652
Mccahill.brendan(@,epa.gov
24
------- |