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Date: September 9, 2011

Subject: Confirmation of Operation of Air Pollution Control Devices (APCDs) for the Top 10 

Sources in the Coal-fired Mercury (Hg), Hydrogen Chloride (HCl), and Particulate Matter 

(PM) Floors 

From: Jeffrey Cole (RTI International)

To: Bill Maxwell

OAQPS/SPPD/ESG (D243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Introduction

The EPA WAM requested that RTI confirm what air pollution control devices (APCDs) were actually in 

operation on the top 10 sources during performance tests used in the coal-fired MACT floor analysis for the 

Hg, HCl, and PM floors.

Background

Through a review of early public comments, the WAM received indications that some APCDs that were

listed as being installed on a given unit may not have been operating during the ICR performance stack

testing. The commenter asserted that the EPA should review these control configurations for accuracy, and 

then instead of choosing the lowest reported emission rate for the new source MACT standard, the EPA 

should choose the controlled source near the lowest emitting source that was actually controlled with the 

control configuration most likely to be placed on a newly built EGU. The commenter believed this approach 

makes the new MACT floor more realistic and achievable. To aide in this evaluation, RTI was requested to 

confirm the APCDs operating during the Hg, HCl, and PM ICR performance testing for the top 10 units in 

Hg, HCl and PM floors and make recommendations as to which top performer reflects the air pollution 

controls configuration most likely required to permit a new EGU.

Technical Approach for Coal-Fired Units

RTI contacted the operators of the top 9 of the 131 units in the PM floor. The 10th unit’s (San Juan, Unit 3) 

APCDs that were in operation during Part III ICR testing were confirmed based on the configuration listed in 

Part I of the ICR and the controls used during Part III testing were noted in the ERT files. For units in the top 

10 of the 131 units in the HCl floor and in the top 10 of the 40 units in the Hg floor, RTI determined the 

APCDs that were in operation during ICR testing by comparing the APCD configurations listed in Part I of 

the ICR with the controls used during Part III testing as noted in the ERT files.

There was a change to unit-ranking within PM floor datasets examined based on information submitted by

operators since proposal. In the PM floor, the previous best unit tested, Bonanza Unit 1, dropped out of the 

top 10 units in the floor upon incorporation of a corrected submittal. This had the effect of shifting each unit 

in the list up one ranking and moving San Juan Unit 3 into the top ten for lowest PM emissions.
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Note that there was one unit in the top ten of the Hg floor units and two units in the top ten HCl floor units 

that were ranked based solely on Part II data. The controls that were in operation during the MACT floor 

performance tests were consistent with the controls listed in their Part I submissions. The Part I controls for 

those units are listed in Tables 2 and 3. 

In order to determine the range of control technologies that would be expected on a new EGU to comply with 

existing major source permitting requirements and to evaluate the impacts of these required control 

technologies on achievability of the MACT emission standards, a review of the RACT/BACT/LAER 

Clearinghouse was conducted for EGU’s permitted since January 1, 2006. This review indicated the 

following predominant technologies:

 Fabric filters were the predominant BACT for PM; twenty-seven of the twenty-nine sources were for 

permitted fabric filters, and two were permitted for ESPs.

 Fifty percent of the listed sources were permitted for dry scrubbers and fifty percent were permitted 

for wet scrubbers as BACT for SO2. 

 For sulfuric acid mist (a primary constituent in condensable PM), the predominant BACT was dry 

sorbent injection either integral to the spray dryer absorber or upstream of a wet scrubber.

 SCRs were the predominant BACT for NOx control.

 Sorbent injection or activated carbon injection was predominant for control of mercury.

Based on this review of the RACT/BACT/LAER Clearinghouse, the air pollution control configuration that 

would be expected on a new EGU permitted under the NSR program would be expected to have the 

following four major components:

1. Either a fabric filter or a high efficiency ESP;

2. Either a wet or dry FGD system;

3. Activated carbon or other sorbent injection;

4. Selective Catalytic Reduction (SCR).

Summary of Findings

 Table 1 shows the confirmed APCDs in operation during MACT floor total PM performance tests 

for the revised top 10 coal-fired units. 

 Table 2 the confirmed APCDs in operation during MACT floor HCl performance tests for the top 10 

coal-fired units. 

 Table 3 shows the confirmed APCDs in operation during MACT floor Hg performance tests for the 

top 10 coal-fired units.
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Particulate Matter (PM)

In the proposed rule, the EPA chose to use Dunkirk Unit 1 (ORIS Code 2554) for the new source total PM 

input-based floor (lb/MMBtu) and Bonanza Unit 1 (ORIS Code 7790) for the new source total PM 

output-based floor (lb/MWh). As stated above the Bonanza Unit 1’s original ranking was based on an 

erroneous submittal and, once corrected, it dropped out of the top 10 units in the total PM floor. Based on the 

comments received it is clear that Dunkirk Unit 1’s control configuration (see highlighted row in Table 1) 

was different during the MACT floor performance tests than the control configuration reported in Part I of 

the ICR because no SNCR or dry sorbent injection system was operating during the ICR stack tests.

Therefore, RTI does not recommend that either of these units continue to be considered for the new floors. In 

addition, we also believe that setting a new MACT based on a unit with only a fabric filter would not be 

reflective of either the best available control technology (BACT) or 112(g) case-by-case MACT that would 

be required under existing major source preconstruction permitting programs:

There are only two units within the top ten with the air pollution control configurations that are typical of the 

predominant BACT technologies:

1. Springerville Unit 4 deploys a dry FGD system. This source is equipped with an SCR, spray dryer 

absorber, and a fabric filter. 

2. Havana Boiler 9 deploys a dry FGD system. This source is equipped with an ESP, SCR, ACI, dry 

scrubber, and a fabric filter.

Because wet scrubbers are effective in removing PM larger than five microns from flue gas, ESPs followed 

by wet scrubbers can also approach the PM emission rates achievable by dry scrubbers with fabric filters as 

reflected by the presence of Roxboro Unit 2 in the top 10. These air pollution control strategies are driven by

state mercury control emissions standards and national fine particulate ambient standards. Requirements to 

deploy these technologies can directly impact a source’s ability to meet the surrogate total PM limit due to 

the significant dust loading added to the flue gas by the controls. The layout of dust from these systems can 

be problematic during startups and shutdowns when the particulate control device may be bypassed (e.g., 

fabric filters) or when the PM control device may be below design temperatures (e.g., ESPs). Additionally, 

these control technologies can pose challenges during malfunctions (e.g., punctured bags) as dust loads 

remain high while operators determine the location of the problem. For these reasons, RTI recommends 

selection of Havana Boiler 9 as the source within the top 10 for PM that reflects the air pollution controls 

typical for new EGUs because this source deploys both ACI and dry sorbent.

Acid Gases

The EPA chose to utilize Logan Unit 1’s (ORIS Code 10043) emission averages in the proposed rule for the 

new HCl floor. This still seems like a good choice, as it is equipped with an SCR, spray dryer absorber and a

fabric filter, which are consistent with the predominant controls found in the RACT/BACT/LAER 

Clearinghouse.

Mercury

Finally, the EPA chose Nucla Unit 1 (ORIS Code 527) in the proposed rule for the Hg floor because the two

Spruance Genco Units (Gen 2 and 3, ORIS Code 54081) are an unusual furnace design that is likely atypical 
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of future new EGU’s. Nucla Unit 1 still appears to be an appropriate choice, as it is equipped with an SCR, 

spray dryer absorber and a fabric filter. These controls are consistent with the predominant controls found in 

the RACT/BACT/LAER Clearinghouse. However, in our review of comments, we have seen concerns that

Nucla Unit 1 is not a good choice for a new floor unit because, in the commenter’s opinion, this unit has a 

“unique” fuel that cannot be reproduced and that yields emission rates that are unachievable by other sources. 

It is worth noting that Logan Unit 1 (ORIS Code 10043) achieved virtually the same Hg emission rate as 

Nucla Unit 1 during MACT floor performance testing. Logan Unit 1 is a conventional, wall-fired unit (as 

compared to Nucla’s FBC), and it is controlled with an SCR, spray dryer absorber and a fabric filter. This 

unit would also be a good choice as a representative unit for newly constructed EGUs.
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Table 1. The Top 10 Units in the Total PM MACT Floor for Coal-fired EGUs

ORIS 

code Plant Name Unit Number Unit Type Boiler Type Boiler Count

Total 

Capacity

MWe

Total max heat 

input

(MMBtu/hr)

Unit heat rate

(MMBtu/MWh)

Fuel type(s)

APCD Controls 

listed at Proposal

Confirmed APCD 

Controls

2554 Dunkirk Generating 

Plant 1

Conventional 

Boiler Tangential firing 1 85 922.2 10.85 subbituminous SNCR, DSI, FF FF

492 Martin Drake Unit 5 -

Coal

Conventional 

Boiler

Wall firing - front 

firing 1 55 570 10.36 subbituminous FF, WFGD FF, WFGD

568 Bridgeport Station

BHSEM

U3OS3-

#2

Conventional 

Boiler Tangential firing 1 403 4100 10.17 subbituminous ESP, ACI, FF ESP, ACI, FF

2712 Roxboro Steam Electric 

Plant

Rox_Cfg

_2c

Conventional 

Boiler Tangential firing 1 703 6893 9.81 bituminous SCR, ESP, WFGD SCR, ESP, WFGD

8223 Springerville 4

Conventional 

Boiler

Wall firing -

opposed firing 1 450 4200 9.33 bituminous SCR, DFGD, FF SCR, DFGD, FF

891 Havana Boiler 9 Conventional 

Boiler

Wall firing -

unspecified 1 481 5030 10.46 bituminous ESP, SCR, ACI, DFGD, FF

ESP, SCR, ACI, 

FF

2554 Dunkirk Generating 

Plant 4

Conventional 

Boiler Tangential firing 1 195 1836 9.42 subbituminous SNCR, DSI, FF FF

7097 J K Spruce 1

Conventional 

Boiler Tangential firing 1 580 6361 10.97 bituminous FF, WFGD FF, WFGD

2324 Reid Gardner 1

Conventional 

Boiler

Wall firing - front 

firing 1 111 1215 10.95 bituminous FF, WFGD FF, WFGD

2451 San Juan Unit 3 Conventional 

Boiler

Wall firing -

opposed firing 1 544 5758 10.58 subbituminous FF, ACI, WFGD FF, ACI, WFGD

Table 2. The Top 10 Units in the HCl MACT Floor for Coal-fired EGUs

ORIS 

code Plant Name Unit Number Unit Type Boiler Type Boiler Count

Total 

Capacity

MWe

Total max heat 

input

(MMBtu/hr)

Unit heat rate

(MMBtu/MWh)

Fuel type(s)

APCD Controls 

listed at Proposal

Confirmed APCD 

Controls

10043 Logan Generating Plant Unit1 Conventional 

Boiler

Wall firing -

opposed firing 1 241.7 2116 8.75 bituminous SCR, DFGD, FF SCR, DFGD, FF

54081 Spruance Genco, LLC GEN3 Conventional 

Boiler Stoker - underfeed 2 57.4 750 13.07 bituminous DFGD, FF DFGD, FF

54081 Spruance Genco, LLC GEN2 Conventional 

Boiler Stoker - underfeed 2 57.4 750 13.07 bituminous DFGD, FF DFGD, FF

3130 Seward SEW-1

Fluidized bed 

firing Fluidized bed firing 2 585 6200 10.60 coal refuse (culm or gob) SNCR, FF SNCR, FF

3130 Seward SEW-2

Fluidized bed 

firing Fluidized bed firing 2 585 6200 10.60 coal refuse (culm or gob) SNCR, FF SNCR, FF

52071 Sandow Station 5A Fluidized bed 

firing Fluidized bed firing 1 282.35 2960 10.48 lignite SNCR, ACI, DFGD, FF

SNCR, ACI, 

DFGD, FF

56224 TS Power Plant TSPower Conventional 

Boiler

Wall firing -

opposed firing 1 242 2112 8.73 subbituminous SCR, ACI, DFGD, FF

SCR, ACI, DFGD, 

FF

3179 Hatfield's Ferry Power 

Station 001 Conventional Boiler

Wall firing -

opposed firing 1 590 5700 9.66 bituminous ESP, WFGD ESP, WFGD

52071 Sandow Station 5B Fluidized bed 

firing Fluidized bed firing 1 282.35 2960 10.48 lignite SNCR, ACI, DFGD, FF

SNCR, ACI, 

DFGD, FF

108 HOLCOMB SGU1 Conventional 

Boiler

Wall firing -

opposed firing 1 387 3389 8.76 subbituminous DFGD, FF DFGD, FF
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Table 3. The Top 10 Units in the Mercury MACT Floor for Coal-fired EGUs

ORIS 

code Plant Name Unit Number Unit Type Boiler Type Boiler Count

Total 

Capacity

MWe

Total max heat 

input

(MMBtu/hr)

Unit heat rate

(MMBtu/MWh)

Fuel type(s)

APCD Controls 

listed at Proposal

Confirmed APCD 

Controls

54081 Spruance Genco, LLC GEN2 Conventional 

Boiler Stoker - underfeed 2 57 750 13.07 bituminous DFGD, FF DFGD, FF

54081 Spruance Genco, LLC GEN3 Conventional 

Boiler Stoker - underfeed 2 57 750 13.07 bituminous DFGD, FF DFGD, FF

527 Nucla 001 Fluidized bed 

firing Fluidized bed firing 1 110 1032 9.38 bituminous FBC, SNCR, FF FBC, SNCR, FF

10043 Logan Generating Plant Unit1 Conventional 

Boiler

Wall firing -

opposed firing 1 242 2116 8.75 bituminous SCR, DFGD, FF SCR, DFGD, FF

3130 Seward SEW-1

Fluidized bed 

firing Fluidized bed firing 2 585 6200 10.60 coal refuse (culm or gob) SNCR, FF SNCR, FF

2527 AES Greenidge Unit 4 Conventional 

Boiler Tangential firing 1 112 1117 9.97 bituminous, petroleum coke

SCR, ACI, DFGD, 

FF

SCR, ACI, DFGD, 

FF

54035 Roanoke Valley I Boiler 1 Conventional 

Boiler

Wall firing - front 

firing 1 182 1700 9.34 bituminous DFGD, FF DFGD, FF

2526 AES Westover, LLC 8

Conventional 

Boiler Tangential firing 1 86 875 10.17 bituminous SCR, DFGD, FF SCR, DFGD, FF

50976 Indiantown 

Cogeneration, L.P. 001 Conventional Boiler

Wall firing -

opposed firing 1 361 3422 9.48 bituminous SCR, DFGD, FF SCR, DFGD, FF

50888

Northampton 

Generating Company, 

L.P.

GEN1 Fluidized bed 

firing Fluidized bed firing 1 121 1146 9.47 coal refuse (culm or gob) FBC, SNCR, FF FBC, SNCR, FF