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MEMORANDUM

DATE: February 19, 2004

SUBJECT: National Impacts Associated with the Final NESHAP for RICE 

FROM: Tanya Ali and Melanie Taylor, Alpha-Gamma Technologies, Inc.

TO: Sims Roy, EPA OAQPS ESD Combustion Group

The purpose of this memorandum is to estimate the national impacts associated with

the final national emission standards for hazardous air pollutants (NESHAP) for

stationary reciprocating internal combustion engines (RICE). The regulation applies to

stationary RICE located at major sources of hazardous air pollutants (HAP) emissions. 

It is estimated that 40 percent of stationary RICE will be located at major sources. 

Impacts discussed in this memorandum include HAP emissions reductions and total

costs associated with regulatory requirements. 

For existing stationary RICE, implementation of the final NESHAP is estimated to

reduce nationwide HAP emissions by 284 tons per year at a total annual cost of $35

million. For new engines, the final regulation is projected to prevent national HAP

emissions by 5,300 tons per year in the fifth year at a total annual cost of $213 million

per year in the fifth year. The total national HAP emissions reductions are the sum of

formaldehyde, acetaldehyde, acrolein, and methanol emissions reductions.

A previous version of this memorandum based on the requirements for the proposed

NESHAP was developed at the time of proposal and entered into the docket (Document

ID Number OAR-2002-0059-0071 or A-95-35 II-B-48). The primary reasons for the

difference in the estimated impacts of the final rule as compared to the proposed rule

are the change in the monitoring requirements for large RICE and the updated HAP

emission factors. The emissions reductions and costs for the final rule are not

substantially different than those for the proposed rule. 

The regulatory requirements of the final rule are presented in Table 1 for the following

four RICE subcategories:

 Two-Stroke Lean Burn (2SLB) Stationary RICE

 Four-Stroke Lean Burn (4SLB) Stationary RICE

 Four-Stroke Rich Burn (4SRB) Stationary RICE
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 Compression Ignition (CI) Stationary RICE. 

Table 1. Summary of Regulatory Requirements for RICE Subcategories

Subcategory Regulatory Requirementa

Existing

4SRB Stationary RICE 76 percent CH2O efficiency or

emission limitation of 350 ppbvd CH2O

2SLB, 4SLB, and CI

Stationary RICE

No emissions reduction

New

2SLB Stationary RICE 58 percent CO efficiency or

emission limitation of 12 ppmvd CH2O

4SLB Stationary RICE 93 percent CO efficiency or

emission limitation of 14 ppmvd CH2O

4SRB Stationary RICE 76 percent CH2O efficiency or

emission limitation of 350 ppbvd CH2O

CI Stationary RICE 70 percent CO efficiency or

emission limitation of 580 ppbvd CH2O

a All concentrations must be corrected to 15 percent oxygen, dry basis.

The nationwide air quality impacts for RICE reaching compliance were estimated

relative to baseline emissions reflecting the emission levels in the absence of any

regulation. Cost impacts are based on the application of the emission controls

necessary to bring the engines into compliance with the final regulation. For engines

where no emissions reduction is required, no impacts were estimated.

Emissions Reductions

The final stationary RICE NESHAP will reduce HAP emissions by an estimated 5,600

tons per year in the fifth year after the rule is promulgated. Emissions of CO, NOx, and

PM will also be reduced by the NESHAP. The calculation of the emissions reductions

of HAP and criteria pollutants associated with the final RICE NESHAP is discussed in

the following sections.

HAP Reduction

For the purpose of estimating emissions reductions, baseline HAP emissions (tons per

year) are calculated using average emission factors from the Emissions Database. 

These emission factors are presented in the memorandum entitled “Revised Emission

Factors for Stationary Reciprocating Internal Combustion Engines.” The sum of the
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HAP Emission Factor (

tons

yr

) 

EFHAP ( lb

hr)  6,500 ( hrsyr

)

2,000 ( lb

ton)

Baseline HAP

Emissions

(

tons

yr

)  [EFHAP (

tons

yr

)  Y  1,829] [EFHAP (

tons

yr

)  Z  (100η)

100  1,829]

average emission factors for formaldehyde, acetaldehyde, acrolein, and methanol

represents the total HAP emission factor. A sample calculation of baseline HAP

emissions for existing 4SRB stationary RICE is provided below:

where:

-EFHAP is the uncontrolled emission factor for HAP in tons/yr.

-6,500 is the average number of operating hours per year for engines in

the Population Database.

-Y is the fraction of uncontrolled 4SRB stationary RICE.

-Z is the fraction of controlled 4SRB stationary RICE. 

-η is the percent reduction for formaldehyde achieved by the catalyst

system. For 4SRB stationary RICE, η=76.

-1,829 is the number of existing 4SRB stationary RICE.

The population of existing RICE and the forecasted population of new RICE for the next

five years is presented in Table 2. Table 3 is a summary of the HAP emissions

reductions associated with the regulatory requirements for the RICE subcategories. 

The following information is included in Table 3:

 Baseline HAP emissions (tons/year) which represent the current emission

level for this subcategory in the absence of MACT regulation,

 HAP emissions with MACT (tons/year) resulting after applying the

regulatory requirement, 

 HAP emissions reductions (tons/year) achieved with each regulatory

requirement, and

 HAP percent reduction corresponding to each regulatory requirement.
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Table 2. Population of RICEa

Engine

Subcategory

HP Rangeb Existing

Population of

Engines

Forecasted Population of New RICE

Total increase of

RICE over 5 years

Annual increase

RICE per year

2SLB Stationary

RICE

500-1,000 565 200 40

1,000-5,000 1,090 None None

5,000-10,000 122 None None

Total 1,777 200 40

4SLB Stationary

RICEc

500-1,000 346 850 170

1,000-5,000 1,238 1,365 273

5,000-10,000 75 5 1

Total 1,660 2,219 444

4SRB

Stationary

RICEd

500-1,000 1,341 743 149

1,000-5,000 486 967 193

5,000-10,000 2 3 1

Total 1,829 1,713 343

CI Stationary

RICE

500-1,000 2,125 2,395 479

1,000-5,000 1,416 1,596 319

5,000-10,000 None None None

Total 3,541 3,991 798

a The presented population excludes stationary RICE that are used as emergency power units and

stationary RICE located at area sources. b There are no existing stationary RICE greater than 10,000 HP and it is predicted that no

stationary RICE greater than 10,000 HP will be sold during the next five years. c 3 percent of existing 4SLB stationary RICE are controlled with a CO oxidation catalyst and it is

predicted that 3 percent of new 4SLB stationary RICE will be controlled with a CO oxidation

catalyst in the absence of this regulation. d 27 percent of existing 4SRB stationary RICE are controlled with NSCR and it is predicted that 27

percent of new 4SRB stationary RICE will be controlled with NSCR in the absence of this

regulation.
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Table 3. Summary of HAP Emissions Reductions for RICE

Engine Subcategory

Baseline HAP

Emissions

(tons/yr)a,b,c

 HAP Emissions

w/MACT (tons/yr)

HAP Emissions

Reduction

(tons/yr)

HAP

Percent

Reduction (%)

from Baselined

 Existing:

 2SLB Stationary RICE 5,762 5,762 0 0.0

 4SLB Stationary RICE 5,206 5,206 0 0.0

 4SRBStationary RICE 407 123 284 69.8

 CI Stationary RICE 465 465 0 0.0

 Total 11,840 11,556 284 2.4

 New:

 2SLB Stationary RICE 130 78 52 40.0

 4SLB Stationary RICE 1,392 497 895 64.3

 4SRB Stationary RICE 76 23 53 69.8

 CI Stationary RICE 105 37 68 65.0

 Total 1,703 634 1,068 62.7

a Baseline HAP emissions from new 4SLB stationary RICE are based on the assumption that 3

percent of new 4SLB stationary RICE would be using an oxidation catalyst achieving 65 percent

formaldehyde efficiency in the absence of the MACT regulation. b Baseline HAP emissions from 4SRB existing and new stationary RICE are based on the

assumption that 27 percent of these stationary RICE are using NSCR achieving 76 percent

formaldehyde efficiency in the absence of the MACT regulation. A sample calculation of

baseline emissions for 4SRB existing stationary RICE is provided in the next footnote. c Baseline HAP Emissions = EFHAP(tons/yr) x [(0.73 x 1,829 existing 4SRB engines) + (0.23 x 0.24

x 1,829 existing 4SRB engines)] d The impact of MACT is on 97 percent of the 4SLB stationary RICE and 73 percent of the 4SRB

stationary RICE.

The MACT for existing engines is estimated to reduce HAP emissions by 284 tons/year

from a baseline level of 11,840 tons/year. The emissions reductions for existing

engines is a result of controlling 4SRB stationary RICE. This represents a 2 percent

emissions reduction from the baseline emission level from all existing engines. This

regulation will have a greater impact on new engines. The MACT floor is estimated to

reduce HAP emissions from all new engines by 1,068 tons/year in the first year from a

baseline level of 1,703 tons/year. This represents a 63 percent HAP emissions

reduction from the baseline level. The baseline level for new engines is the emission

level one would expect to see in the absence of any regulation. The largest reduction

in HAP emissions from new engines is a result of controlling 4SLB stationary RICE,

which have an emissions reduction of 895 tons/year in the first year, representing 84
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percent 

of the total HAP emissions reductions from new engines.

Criteria Pollutant Reduction

A benefit of this regulation is that it is expected to reduce criteria emissions in addition

to HAP emissions. A summary of the total reduction in criteria pollutants as a result of

the MACT rule is given in Table 4. Oxidation catalysts (used on either lean burn or rich

burn engines) and NSCR (used on rich burn engines) are capable of reducing CO by

as much as 95 percent at ideal conditions. The regulation is projected to reduce CO

emissions by 234,400 tons per year at the end of the fifth year following promulgation. 

Oxidation catalysts used on CI stationary RICE are also capable of reducing total

particulate emissions by 25 to 50 percent. The total estimated PM emissions reduction

in the fifth year is estimated to be 3,700 tons per year.

The application of NSCR controls to 4SRB engines will also reduce NOx emissions by

90 percent. Assuming that 60 percent of 4SRB (new and existing) engines that are

covered by the emission standards will use NSCR, the cumulative emissions reductions

of NOx by the end of the fifth year after promulgation are calculated to be about

167,900 tons per year.

Control Costs

It has been determined by EPA that oxidation catalysts, such as CO oxidation catalyst

and NSCR, are applicable controls for the reduction of HAP from stationary RICE. The

costs associated with these add-on control devices were gathered by EPA and are

summarized in the memorandum entitled “Control Costs for Reciprocating Internal

Combustion Engines.” In order to estimate national impacts associated with controlling

RICE emissions, control cost estimates for engines were extrapolated to the actual

population of engines in the United States, and national impacts were then determined. 

Cost impacts include the total capital investment of new control equipment, the cost of

energy (utilities) required to operate the control equipment, operation and maintenance

costs, and the cost of monitoring.

Table 5 lists the capital control costs and annual control costs associated with each

model engine in dollars per horsepower. Control costs per engine are then

extrapolated to the existing population and forecasted number of new engines to obtain

total control costs for the entire existing population and for the predicted number of new

RICE. Total control costs and total annual control costs for existing RICE are

presented in Table 6 and for new stationary RICE in Table 7. Costs of monitoring are

presented in Table 8 for each of the engine subcategories. For 4SRB engines, the

monitoring costs are different for different size engines due to larger engines having

different monitoring requirements. The monitoring costs for 2SLB, 4SLB, and CI RICE

are the same for all size engines.
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Table 4. Summary of Criteria Pollutant Emissions Reductions in the First Year

Engine Subcategory Pollutant Percent

Reduction (%)

Total Emission

 Reductiona

 (tons/yr)

Existing 4SRB Stationary RICE CO 90 98,040

NOx 90 69,862

New 2SLB Stationary RICE CO 58 391

New 4SLB Stationary RICE CO 93 7,248

New 4SRB Stationary RICE CO 90 18,364

NOx 90 98,023

New CI Stationary RICE CO 70 1,264

PM 25 3,746

a Total emissions reduction is based on the population of RICE obtained from Table 2. The

reduction in this table is the reduction in the first year.

Cost Impacts

A summary of total baseline HAP emissions, total HAP emissions reductions, total

capital investment and total annual costs for all existing and new RICE in the first year

is presented in Table 9. The total national capital cost for this rule for existing

stationary RICE is estimated to be approximately $68 million, with a total national

annual cost of $35 million. The total national capital cost for this rule for new stationary

RICE by the 5th year is estimated to be approximately $371 million, with a total national

annual cost of $213 million in the 5th year.

Energy Impacts

Energy impacts associated with this regulation would be due to additional energy

consumption that the regulation would require by installing and operating control

equipment. The only energy requirement for the operation of the control technologies

is due to a small increase in fuel consumption resulting from back pressure caused by

the control system. This energy impact is however considered minimal in comparison

to cost of other impacts, and is therefore considered negligible.
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Table 5. Control Costs Associated with Model Engines

Model Engines HP 

Rating

Capital

Control

Cost per

model

engine

($)

Annual

Control

Cost per

model

engine

($/yr)

Capital

Control

Cost per

model

engine 

($ per HP)

Annual Control

Cost 

per model

engine

($ per HP/yr)

Cost of

Engine 

($)a

Clark RA6 600 13,299 7,339 22 12 115,626b

Cooper Bessemer GMV10 1100 27,072 13,851 25 13 173,755b

Cooper Bessemer

GMV10TC

1350 30,777 16,527 23 12 365,359b

Cooper Bessemer 10V250 3800 72,003 43,646 19 11 1,377,059c

Worthington ML20 7500 121,112 82,202 16 11 2,904,933b

2SLB Average: 21 12

Caterpillar 3512 1000 14,344 10,730 14 11 192,710d 

Caterpillar 3512 1220 21,325 13,763 17 11 192,710d 

Waukesha 7042 GL 1478 28,497 17,135 19 12 400,000 

Cooper Bessemer LSV16G 5200 84,352 57,098 16 11 2,014,087e

4SLB Average: 17 11

Waukesha F3521 GSI 738 27,833 11,094 38 15 246,454e

Waukesha 7042 G 1024 32,012 14,144 31 14 300,000f

Waukesha L7042 GSI 1478 40,690 19,532 28 13 385,000

4SRB Average: 32 14

Detroit 16V71 510 12,102 6,401 24 13 76,500g

Caterpillar D399 750 11,399 8,193 15 11 112,500h

Detroit 12V92 818 13,964 9,205 17 11 122,700g

Cummins KTA50 1850 31,775 20,709 17 11 500,677b

Detroit 16V149 1965 22,399 19,919 11 10 531,800b

CI Average: 17 11

a Costs of engines are suggested retail costs, representing the costs for a standard engine not including any

additional options an engine might require, and are therefore to be considered minimum. Also note that

installation will add a significant amount to the capital cost depending on the use and size of the engine. b Cost estimated based on $/HP for 4SLB engines for each HP rating segment. c Cost estimated by interpolation. d Cost estimate based on the cost of 4SLB engine 3512 G, with a horsepower rating of 800. e Cost estimated by extrapolation. f Cost estimate based on the cost of 4SRB engine L7042 GU, with a horsepower rating of 901.

g Cost estimated based on $/HP for CI engines for each HP rating segment. h Cost estimate is the average of the cost of CI engines RICE 3516 (1200 HP) and 3306 (375 HP).
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Table 6. Total Control Costs Associated with Existing RICE

Engine

Subcategorya

HP Rangeb Total #

Engines

Average

HP

 Control

Cost per

enginec

($/engine)

 Annual

Control Cost

per enginec

($/yr)

Total

Control

Costd

($1,000)

Total Annual

Control Costd

($1,000/yr)

4SRB

Stationary

RICE

500-1,000 1,341 750 24,000 10,500 23,498 10,280

1,000-5,000 486 3,000 96,000 42,000 34,067 14,905

5,000-10,000 2 7,500 240,000 105,000 340 149

Total 57,906 25,334

a Existing 2SLB, 4SLB, and CI engines have no emissions reduction requirement and therefore no control cost

associated with the regulation. b There are no existing stationary RICE greater than 10,000 HP, and the presented population excludes emergency

power units, engines 500 HP or less, and engines at area sources. c Control costs are calculated using the average HP for the HP range in question, multiplied times the average control

cost in $ per HP, obtained from Table 5. d Total control cost and total annual control cost were not included for 27 percent of the existing 4SRB stationary

RICE, since these engines would be controlled in the absence of the regulation.
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Table 7. Total Control Costs Associated with New RICE

Engine

Subcategory

HP Rangea Engine

increase

per year

Average

HP

 Control

Cost

 per engineb

($/engine)

 Annual

Control Cost

per engineb

($/yr)

Total

Control

Cost 

($1,000)

Total Annual

Control Cost 

($1,000/yr)

2SLB

Stationary

RICE

500-1,000 40 750 15,750 9,000 630 360

4SLB

Stationary

RICE

500-1,000 170 750 12,750 8,250 2,101 1,360

1,000-5,000 273 3000 51,000 33,000 13,503 8,737

5,000-10,000 1 7,500 127,500 82,500 119 77

Total 15,724 10,174

4SRB

Stationary

RICE

500-1,000 149 750 24,000 10,500 2,604 1,139

1,000-5,000 193 3,000 96,000 42,000 13,551 5,928

5,000-10,000 1 7,500 240,000 105,000 112 49

Total 16,267 7,117

CI 

Stationary

RICE

500-1,000 479 750 12,750 8,250 6,107 3,951

1,000-5,000 319 3,000 51,000 33,000 16,284 10,537

5,000-10,000 0 7,500 127,500 82,500 0 0

Total 22,391 14,448 

a No stationary RICE greater than 10,000 HP are expected to be sold during the next five years. b Control costs are calculated using the average HP for the HP range in question, multiplied times the average control

cost in $ per HP, obtained from Table 5. 
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Table 8. Costs of Monitoring for RICE Subcategories

Engine

Subcategory

HP Range Monitoring

Capital Cost

($/engine)

Monitoring

Annual Cost

($/engine)

Total

Monitoring

Capital Cost

($1,000)

Total

Monitoring

Annual Cost

($1,000)

Existing 4SRB 500-5,000 5,699 4,487 10,414 8,199

5,000-10,000 5,699 13,383 11 26

4SRB Total 10,425 8,225

New 2SLB all 13,479 5,959 539 238

New 4SLB all 13,479 5,959 5,983 2,645

New 4SRB 500-5,000 5,699 4,487 1,949 1,535

5,000-10,000 5,699 13,383 4 9

4SRB Total 1,953 1,544

New CI all 13,479 5,959 10,760 4,757
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Table 9. Summary of HAP Emissions Reductions and Cost Impacts Associated with the R

Engine

Subcategory

Existing Engines New Engines

Baseline

Emissions

(ton/yr)

HAP

Emissions

Reduction

(ton/yr)

Total

Capital

Investment

($1,000)a

Total

Annual 

Cost 

($1,000)a

Baseline

Emissions

(ton/yr)

HAP

Emissions

Reduction

(ton/yr)

To

Cap

Invest

($1,0

2SLB StationaryRICE

5,762 0 0 0 130 52 1,1

4SLB StationaryRICE

5,206 0 0 0 1,392 895 21,7

4SRB StationaryRICE

407 284 68,331 34,566 76 53 18,2

CI StationaryRICE

465 0 0 0 105 68 33,1

Total: 11,840 284 68,331 34,566 1,703 1,068 74,2

a Total capital investment and total annual costs include the cost of control, monitoring, testing, recordkeeping, and b In this table, the air and cost impact estimates for new engines are presented for the first year.
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References:

1. Memorandum from Taylor, M., Alpha-Gamma Technologies, Inc., to Sims Roy,

EPA OAQPS ESD Combustion Group. January 20, 2004. Revised Emission

Factors for Stationary Reciprocating Internal Combustion Engines.

2. Memorandum from Snyder, J. and M. Taylor, Alpha-Gamma Technologies, Inc.,

to Sims Roy, EPA OAQPS ESD Combustion Group. January 7, 2002. Control

Costs for Reciprocating Internal Combustion Engines. 

3. Memorandum from Snyder, J., Alpha-Gamma Technologies, Inc., to Sims Roy,

EPA OAQPS ESD Combustion Group. November 28, 2001. Population of

Stationary Reciprocating Internal Combustion Engines: Summary.

4. Catalyst Manual, Installation, Operation, and Troubleshooting. Published by

Miratech Corporation, Tulsa, Oklahoma, October 1998.

5. The Impact of Sulfur in Diesel Fuel on Catalyst Emission Control Technology. 

Manufacturers of Emission Control Association, Washington, DC, March 15,

1999.

6. Personal Communication from Snyder, J., Alpha-Gamma Technologies, Inc. to

Heater, B., Cooper Energy Services. January 31, 2000.

7. Facsimile transmission from Wheless, E., County Sanitation District of Los

Angeles County, to Snyder, J., Alpha-Gamma Technologies, Inc. December 13,

1999. Draft of Landfill Gas Utilization Survey of United States Projects.

8. Personal Communication from Snyder, J., Alpha-Gamma Technologies, Inc. to

Tripp, J., Gregory Poole Equipment. February 2, 2000.

9. Association of Metropolitan Sewerage Agencies (AMSA) Population Database. 

Sent by Torres, E., AMSA to Porter, F., U.S. Environmental Protection Agency. 

September 30, 1997.