Date: September 30, 2011

Subject: National Emission Standards for Hazardous Air Pollutants (NESHAP) 

for Coal- and Oil-Fired Electric Utility Steam Generating Units

Response to Comments Regarding Inaccurate Heat Rates in MACT 

Floor Analysis

From: Shelly Johnson

To: William Maxwell

OAQPS/SPPD/ESG (D243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

I. Background

The EPA proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for 

Coal- and Oil-Fired Electric Utility Steam Generating Units (EGUs) on May 3, 2011. The 

public comment period ended on July 5, 2011. The Electric Power Research Institute (EPRI) 

commented on the unit heat rates used in the maximum achievable control technology

(MACT) floor analysis. They stated, “Heat rates were calculated incorrectly for 53 EGUs 

listed in the MACT floor spreadsheets. These errors resulted in emissions on a pound per 

megawatt-hour (lb/MWh) basis that are two to six times too low. EGUs affected by this error 

include several identified as lowest emitting in the MACT floor spreadsheets.” In addition to 

this comment, EPA has received other comments indicating that the heat rates used to 

convert emissions on a lb/MMBtu basis to a lb/MWh basis are not realistic.

This memorandum addresses the work done to identify facilities with heat rates that appear to 

be inaccurate, and to revise that information in the EGU MACT Information Collection 

Request (ICR) database.

II. Discussion

The heat rates used in the MACT floor analysis are calculated based on data provided by

each company in response to the EGU MACT ICR. The boiler information table contains

detailed boiler-specific operating parameters for each boiler at a facility. These parameters 

include the present maximum heat input (MMBtu/hr) and summer gross generating capacity 

(MWe). These company-provided parameters are used to calculate the heat rate for each 

boiler. The heat rate is calculated by dividing the maximum heat input by the summer gross 

generating capacity to obtain a heat rate in units of MMBtu/MWh. 
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Most boilers have a calculated heat rate between 8 and 14 MMBtu/MWh. The boilers with 

calculated heat rates lower than 8 MMBtu/MWh, and plants with multiple boilers serving one 

generator were reviewed to confirm the maximum heat input and summer gross generating 

capacity values that were provided in response to the ICR.

The most common reason for the low calculated heat rates is that the generation values for 

the turbine generator were entered for each boiler that supplies steam to the generator. For 

instance, if twin boilers provide steam to a single turbine generator that produces 200 MW of 

electricity, each boiler is (ostensibly) responsible for one-half of the electricity generated. 

Therefore, the summer gross generating capacity value should have been reported as 100 

MWe for each boiler; however, in many cases the full 200 MW was entered as the capacity 

for each boiler.

III. Conclusion

In total, 25 facilities were contacted to confirm the maximum heat inputs and gross 

generating capacities of 59 boilers. All of the 53 units EPRI suggested are included in the 59 

boilers that were corrected. For the 11 facilities that did not respond to our request for 

additional information, the heat inputs and generating capacities were revised based on 

information included in the NEEDS database (v4.10). The original values from the ICR 

response and the corrected values are shown in Attachment 1, Table A-1. All revisions have 

been made in the ICR database and will be reflected in future outputs of the MACT floor 

data.
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ATTACHMENT 1
4

Table A-1: Boilers with corrected maximum heat inputs and summer gross generating capacities.

ORIS 

Code Boiler ID

Original Max 

Heat Input

 Original

Summer Gross 

Generating 

Capacity 

Original Unit 

Heat Rate

New Max 

Heat Input

New Summer 

Gross 

Generating 

Capacity

New Unit Heat 

Rate

Source of Confirmation

MMBtu/hr MWe MMBtu/MWh MMBtu/hr Mwe MMBtu/MWh

508 4 180 44.0 4.09 510 44.0 11.59 Company contact

703 3 7,284 933.0 7.81 8,185 933.0 8.77 NEEDS comparison

1004 6-1 510 171.0 2.98 510 42.8 11.93 NEEDS comparison

1004 7-1 510 171.0 2.98 510 42.8 11.93 NEEDS comparison

1004 7-2 510 171.0 2.98 510 42.8 11.93 NEEDS comparison

1004 8-1 510 171.0 2.98 510 42.8 11.93 NEEDS comparison

2526 11 273 46.0 5.93 273 23.0 11.87 NEEDS comparison

2526 12 273 46.0 5.93 273 23.0 11.87 NEEDS comparison

2712 3A 3,460 741.0 4.67 3,460 370.5 9.34 Company contact

2712 3B 3,460 741.0 4.67 3,460 370.5 9.34 Company contact

2712 4A 3,469 745.0 4.66 3,469 372.5 9.31 Company contact

2712 4B 3,469 745.0 4.66 3,469 372.5 9.31 Company contact

2864 5 647 100.0 6.47 647 50.0 12.94 NEEDS comparison

2864 6 647 100.0 6.47 647 50.0 12.94 NEEDS comparison

3178 1 1,250 184.0 6.79 1,749 184.0 9.51 Company contact

3178 2 1,204 183.0 6.58 1,706 183.0 9.32 Company contact

3776 51 572 100.0 5.72 572 50.0 11.44 Company contact

3776 52 572 100.0 5.72 572 50.0 11.44 Company contact

6190 3-1 2,808 703.8 3.99 2,808 351.9 7.98 NEEDS comparison

6190 3-2 2,808 703.8 3.99 2,808 351.9 7.98 NEEDS comparison

6250 1A 3,743 792.0 4.73 3,743 396.0 9.45 Company contact

6250 1B 3,743 792.0 4.73 3,743 396.0 9.45 Company contact

7537 1A 614 90.0 6.82 614 45.0 13.64 Company contact

7537 1B 629 90.0 6.99 629 45.0 13.98 Company contact

8048 1 3,669 517.0 7.10 4,964 535.0 9.28 Company contact

8048 2 3,933 525.0 7.49 4,850 525.0 9.24 Company contact

10151 BLR1A 675 95.0 7.11 675 47.5 14.21 Company contact

10151 BLR1B 675 95.0 7.11 675 47.5 14.21 Company contact

10384 1A 375 61.0 6.15 375 30.5 12.30 Company contact

10384 1B 375 61.0 6.15 375 30.5 12.30 Company contact

10384 2A 375 61.0 6.15 375 30.5 12.30 Company contact

10384 2B 375 61.0 6.15 375 30.5 12.30 Company contact

10566 Boil 1 1,387 285.0 4.87 1,387 142.5 9.73 Company contact

10566 Boil 2 1,387 285.0 4.87 1,387 142.5 9.73 Company contact

10671 1A 3,553 283.9 12.51 1,110 80.0 13.88 Company contact

10671 1b 3,553 283.9 12.51 1,110 80.0 13.88 Company contact

10671 2a 3,553 283.9 12.51 1,110 80.0 13.88 Company contact

10671 2b 3,553 283.9 12.51 1,110 80.0 13.88 Company contact

10672 CBA 1,063 280.0 3.80 1,063 92.0 11.55 Company contact

10672 CBB 1,063 280.0 3.80 1,063 92.0 11.55 Company contact

10672 CBC 1,063 280.0 3.80 1,063 92.0 11.55 Company contact

10673 BLR A 1,021 203.0 5.03 1,021 101.5 10.06 NEEDS comparison

10673 BLR B 944 203.0 4.65 944 101.5 9.30 NEEDS comparison

10675 A 1,002 208.0 4.82 1,002 104.0 9.63 NEEDS comparison

10675 B 1,002 208.0 4.82 1,002 104.0 9.63 NEEDS comparison

10676 2 550 135.0 4.07 550 38.4 14.32 NEEDS comparison

10676 3 550 135.0 4.07 550 38.4 14.32 NEEDS comparison

10676 4 550 135.0 4.07 550 38.4 14.32 NEEDS comparison

10676 5 285 135.0 2.11 285 19.8 14.39 NEEDS comparison

10743 CFB1 457 58.0 7.88 457 29.0 15.76 NEEDS comparison

10743 CFB2 453 58.0 7.81 453 29.0 15.62 NEEDS comparison

10771 10771-01 433 68.0 6.37 433 34.0 12.74 Company contact

10771 10771-02 422 68.0 6.21 422 34.0 12.41 Company contact

10774 1 442 68.0 6.50 442 34.0 13.00 Company contact

10774 2 447 68.0 6.57 447 34.0 13.15 Company contact

50835 1 408 64.4 6.34 408 32.2 12.67 NEEDS comparison

50835 2 408 64.4 6.34 408 32.2 12.67 NEEDS comparison

50974 #1 CFB boiler 650 97.0 6.70 650 48.5 13.40 NEEDS comparison

50974 #2 CFB Boiler 600 97.0 6.19 600 48.5 12.37 NEEDS comparison