E

C

/R Incorporated Providing Environmental Technical Support Since 1989

501 Eastowne Drive, Suite 325  Chapel Hill, North Carolina 27514

Telephone: (919) 484-0222  Fax: (919) 484-0122

 

MEMORANDUM

DATE: August 10, 2010

SUBJECT: Cost per Ton of HAP Reduced for Existing Stationary SI RICE

FROM: Bradley Nelson and Tanya Parise, EC/R, Inc.

TO: Melanie King, EPA OAQPS/SPPD/ESG

1.0 PURPOSE

The purpose of this memorandum is to present the cost per ton of reducing hazardous air 

pollutants (HAP) emissions from existing stationary spark ignition (SI) reciprocating internal 

combustion engines (RICE). In addition to HAP, this memorandum also presents the cost per 

ton of reducing carbon monoxide (CO), volatile organic compounds (VOC), and nitrogen oxides 

(NOx). In terms of aftertreatment controls that reduce HAP emissions from stationary SI 

engines, the applicable technologies are oxidation catalyst for lean burn SI engines and nonselective catalytic reduction (NSCR) for rich burn SI engines.

2.0 COST OF CONTROLS

The capital and annual cost of HAP control technology for SI engines controls were 

developed using equipment cost information obtained from control technology vendors and 

industry groups, and the estimation methodology outlined in the EPA Air Pollution Control Cost 

Manual.1 The development of the cost equations for each of the applicable control technologies 

is presented in a control cost memorandum.2 EPA determined that the following cost equations 

in Table 1 are representative of the applicable add-on controls to be considered for stationary SI 

engines.

 

1 EPA Air Pollution Control Cost Manual Sixth Edition, January 2002, EPA/452/B-02-001.

2 Memorandum from Bradley Nelson, EC/R Inc., to Melanie King, EPA OAQPS/SPPD/ESG, Control Costs for 

Existing Stationary SI RICE, June 29, 2010 .
2

Table 1. Annual and Capital Costs Equations

HAP Control Device Annual Cost ($2009) Capital Cost ($2009)

Oxidation Catalyst (2SLB) $11.4 x HP + $13,928 $47.1 x HP + $41,603

Oxidation Catalyst (4SLB) $1.81 x HP + $3,442 $12.8 x HP + $3,069

NSCR (4SRB) $4.77 x HP + $5,679 $24.9 x HP + $13,118

3.0 EMISSION REDUCTIONS

Uncontrolled emissions, i.e., emissions without add-on controls were calculated using the 

emission factors presented in Table 2 of this memorandum and assuming that non-emergency SI 

engines operate on average for 2,800 hours per year (hrs/yr) and emergency SI engines operate 

on average for 50 hrs/yr. Emissions reductions for the control technologies were estimated using 

control efficiencies presented in a previous memorandum developed for the 2004 RICE 

NESHAP.3 The memorandum presents oxidation catalyst and NSCR control efficiencies

observed during testing of a 2-stroke lean burn (2SLB) engines and a 4-stroke lean burn (4SLB) 

engine with oxidation catalyst, and a 4-stroke rich burn (4SRB) engine with NSCR. EPA used 

the average percent reduction observed during testing in order to estimate emissions reductions, 

which are also presented in Table 2 of this memorandum.

Table 2. Summary of SI Engine Emission Factors

Engine Type Pollutant Emission Factor 

(lb/HP-hr) Percent Reduction

2SLB

HAP 5.96E-04 43%

CO 1.06E-02 65%

VOC 3.07E-03 43%

4SLB

HAP 5.41E-04 71%

CO 3.92E-03 94%

VOC 2.78E-03 71%

4SRB

HAP 2.43E-04 76%

CO 1.93E-02 49%

VOC 1.25E-03 76%

NOx

1

1.47E-02 97%

1

Emission factors for NOx are not presented for 2SLB and 4SLB SI engines, because no 

emission reductions are expected from the use of an oxidation catalyst. 

 

3 Memorandum from Melanie Taylor and Jennifer Snyder, AGTI to Sims Roy, EPA OAQPS ESD Combustion 

Group, CO Removal Efficiency as a Surrogate for HAP removal Efficiency, January 7, 2004.
3

For existing stationary 2SLB and 4SRB engines greater than or equal to 100 horsepower 

(HP) and less than or equal to 500 HP at major sources, the maximum achievable control 

technology (MACT) floor is a numerical emission limit that is based on emissions data from the 

best controlled 12 percent of engines in the emissions data set. These engines were not equipped 

with add-on emission controls, therefore, the cost to comply with the MACT floor would only

include the cost of demonstrating that the requirements are met by performing testing, 

monitoring, recordkeeping and reporting, and not the cost of add-on controls. EPA looked at 

going beyond-the-floor for these engines by requiring emission levels expected with using addon controls. Since the cost to demonstrate compliance is already included at the MACT floor 

level, costs associated with going beyond-the-floor would include the cost of add-on controls. 

Consequently, the cost per ton values are estimated using the cost of add-on controls only. For 

stationary 4SLB engines greater than or equal to 100 HP and less than or equal to 500 HP at 

major sources, the best controlled 12 percent of engines in the emissions data set for 4SLB 

engines used add on controls, and the MACT floor reflects this fact. The cost per ton values for 

existing stationary 2SLB, 4SLB and 4SRB engines at major sources are presented in Tables 3, 4, 

and 5. The cost per ton values for stationary 2SLB and 4SRB engines represent the costs for 

going beyond-the-floor. The cost per ton values for 4SLB engines represent the costs at the 

MACT floor.

For existing stationary 2SLB, 4SLB and 4SRB engines at area sources, the generally 

available control technology (GACT) is management practices. Performance testing, 

monitoring, recordkeeping and reporting would not be necessary with GACT, or management 

practices. EPA looked at going beyond GACT for these engines by requiring emission levels 

expected with using add-on controls. Consequently, the cost per ton values are estimated using 

the cost of add-on controls, plus the cost of demonstrating compliance, Therefore, the cost per 

ton values for engines are area sources include the cost of performance testing, monitoring, 

recordkeeping, and reporting, in addition to the cost of add-on controls for existing stationary

engines at area sources. The cost per ton values for existing stationary 2SLB, 4SLB, and 4SRB 

engines at area sources are presented in Tables 6 through 8. 

4.0 BENEFITS

The benefits per ton of PM2.5 precursors VOC and NOx at 3 percent interest rate is $1,200 

to $3,000 and $4,900 to $12,000 respectively. The benefits per ton of VOC and NOx at 7 percent 

interest rate is $1,100 to $2,700 and $4,400 to $12,000 respectively. For more information on 

the benefits per ton of pollutants reduced and total monetized benefits, please refer to the 

“Regulatory Impact Analysis (RIA) for Existing Stationary Spark Ignition Engines NESHAP,” 

which can be found in the docket (EPA-HQ-OAR-2008-0708). 
Table 3. Cost per ton ($/ton) of HAP, CO, and VOC Reduced per 2SLB Engine ($2009)-Major Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 100 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $42,781 $46,313 $48,668 $53,378 $55,733 $65,153 $76,928 $88,703

Annual Cost of HAP Control ($2009/yr) $14,213 $15,068 $15,638 $16,778 $17,348 $19,628 $22,478 $25,328

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0209 0.0834 0.1252 0.2086 0.2503 0.4172 0.6258 0.8344

HAP Emission Reductions (Tons/yr) 0.0090 0.0360 0.0541 0.0901 0.1081 0.1802 0.2703 0.3605

Annual Cost of Control per Ton of HAP Removed ($/Ton) $1,577,203 $418,020 $289,222 $186,184 $160,424 $108,905 $83,145 $70,266

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.37 1.48 2.23 3.71 4.45 7.42 11.13 14.84

CO Emission Reductions (Tons/yr) 0.24 0.96 1.44 2.40 2.88 4.79 7.19 9.59

Annual Cost of Control per Ton of CO Removed ($/Ton) $59,303 $15,718 $10,875 $7,001 $6,032 $4,095 $3,126 $2,642

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.107 0.429 0.644 1.073 1.288 2.146 3.219 4.292

VOC Emission Reductions (Tons/yr) 0.046 0.185 0.278 0.464 0.556 0.927 1.391 1.854

Annual Cost of Control per Ton of VOC Removed ($/Ton) $306,608 $81,263 $56,225 $36,194 $31,186 $21,171 $16,163 $13,660
5

Table 4. Cost per ton ($/ton) of HAP, CO, and VOC Reduced per 4SLB Engine ($2009)-Major Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 50 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $3,389 $3,709 $4,989 $6,269 $6,909 $9,469 $12,669 $15,869

Annual Cost of HAP Control ($2009/yr) $3,487 $3,533 $3,714 $3,895 $3,985 $4,347 $4,800 $5,252

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0189 0.0379 0.1136 0.1894 0.2272 0.3787 0.5681 0.7574

HAP Emission Reductions (Tons/yr) 0.0135 0.0269 0.0808 0.1346 0.1616 0.2693 0.4039 0.5385

Annual Cost of Control per Ton of HAP Removed ($/Ton) $259,029 $131,195 $45,972 $28,928 $24,667 $16,145 $11,883 $9,753

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.14 0.27 0.82 1.37 1.65 2.74 4.12 5.49

CO Emission Reductions (Tons/yr) 0.13 0.26 0.77 1.29 1.55 2.58 3.87 5.16

Annual Cost of Control per Ton of CO Removed ($/Ton) $27,040 $13,695 $4,799 $3,020 $2,575 $1,685 $1,240 $1,018

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.10 0.19 0.58 0.97 1.17 1.95 2.92 3.90

VOC Emission Reductions (Tons/yr) 0.07 0.14 0.42 0.69 0.83 1.39 2.08 2.77

Annual Cost of Control per Ton of VOC Removed ($/Ton) $50,355 $25,504 $8,937 $5,624 $4,795 $3,138 $2,310 $1,896
6

Table 5. Cost per ton ($/ton) of HAP, CO, VOC, and NOx Reduced per 4SRB Engine ($2009)-Major Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 50 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $13,741 $14,363 $16,853 $19,343 $20,588 $25,568 $31,793 $38,018

Annual Cost of HAP Control ($2009/yr) $5,798 $5,918 $6,395 $6,872 $7,110 $8,064 $9,257 $10,449

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0085 0.0170 0.0510 0.0851 0.1021 0.1701 0.2552 0.3402

HAP Emission Reductions (Tons/yr) 0.0065 0.0129 0.0388 0.0647 0.0777 0.1294 0.1942 0.2589

Annual Cost of Control per Ton of HAP Removed ($/Ton) $895,855 $457,140 $164,663 $106,168 $91,544 $62,296 $47,672 $40,360

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.68 1.35 4.05 6.76 8.11 13.51 20.27 27.02

CO Emission Reductions (Tons/yr) 0.33 0.66 1.98 3.30 3.96 6.61 9.91 13.21

Annual Cost of Control per Ton of CO Removed ($/Ton) $17,553 $8,957 $3,226 $2,080 $1,794 $1,221 $934 $791

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.04 0.09 0.26 0.44 0.53 0.88 1.31 1.75

VOC Emission Reductions (Tons/yr) 0.03 0.07 0.20 0.33 0.40 0.67 1.00 1.33

Annual Cost of Control per Ton of VOC Removed ($/Ton) $174,154 $88,868 $32,011 $20,639 $17,796 $12,110 $9,268 $7,846

Non-Emergency Engines - NOx

Uncontrolled NOx Emissions (Tons/yr) 0.51 1.03 3.09 5.15 6.17 10.29 15.44 20.58

NOx Emission Reductions (Tons/yr) 0.50 1.00 3.00 5.00 6.00 10.00 15.00 20.00

Annual Cost of Control per Ton of NOx Removed ($/Ton) $11,594 $5,916 $2,131 $1,374 $1,185 $806 $617 $522
7

Table 6. Cost per ton ($/ton) of HAP, CO, and VOC Reduced per 2SLB Engine ($2009)-Area Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 100 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $43,349 $46,881 $49,236 $53,946 $56,301 $65,721 $77,496 $89,271

Annual Cost of HAP Control ($2009/yr) $17,659 $18,514 $19,084 $20,224 $20,794 $23,074 $25,924 $28,774

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0209 0.0834 0.1252 0.2086 0.2503 0.4172 0.6258 0.8344

HAP Emission Reductions (Tons/yr) 0.0090 0.0360 0.0541 0.0901 0.1081 0.1802 0.2703 0.3605

Total Annual Cost per Ton of HAP Removed ($/Ton) $1,959,602 $513,620 $352,956 $224,424 $192,291 $128,025 $95,892 $79,826

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.37 1.48 2.23 3.71 4.45 7.42 11.13 14.84

CO Emission Reductions (Tons/yr) 0.24 0.96 1.44 2.40 2.88 4.79 7.19 9.59

Total Annual Cost per Ton of CO Removed ($/Ton) $73,682 $19,312 $13,271 $8,438 $7,230 $4,814 $3,606 $3,001

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.107 0.429 0.644 1.073 1.288 2.146 3.219 4.292

VOC Emission Reductions (Tons/yr) 0.046 0.185 0.278 0.464 0.556 0.927 1.391 1.854

Total Annual Cost per Ton of VOC Removed ($/Ton) $380,947 $99,848 $68,615 $43,628 $37,381 $24,888 $18,641 $15,518
8

Table 7. Cost per ton ($/ton) of HAP, CO, and VOC Reduced per 4SLB Engine ($2009)-Area Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 50 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $3,957 $4,277 $5,557 $6,837 $7,477 $10,037 $13,237 $16,437

Annual Cost of HAP Control ($2009/yr) $6,933 $6,978 $7,159 $7,340 $7,431 $7,793 $8,245 $8,698

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0189 0.0379 0.1136 0.1894 0.2272 0.3787 0.5681 0.7574

HAP Emission Reductions (Tons/yr) 0.0135 0.0269 0.0808 0.1346 0.1616 0.2693 0.4039 0.5385

Total Annual Cost per Ton of HAP Removed ($/Ton) $514,993 $259,177 $88,633 $54,524 $45,997 $28,943 $20,416 $16,152

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.14 0.27 0.82 1.37 1.65 2.74 4.12 5.49

CO Emission Reductions (Tons/yr) 0.13 0.26 0.77 1.29 1.55 2.58 3.87 5.16

Total Annual Cost per Ton of CO Removed ($/Ton) $53,759 $27,055 $9,252 $5,692 $4,802 $3,021 $2,131 $1,686

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.10 0.19 0.58 0.97 1.17 1.95 2.92 3.90

VOC Emission Reductions (Tons/yr) 0.07 0.14 0.42 0.69 0.83 1.39 2.08 2.77

Total Annual Cost per Ton of VOC Removed ($/Ton) $100,115 $50,384 $17,230 $10,600 $8,942 $5,626 $3,969 $3,140
9

Table 8. Cost per ton ($/ton) of HAP, CO, VOC, and NOx Reduced per 4SRB Engine ($2009)-Area Sources

Engine Data Engine Size (HP)

Average Engine Horsepower 25 50 150 250 300 500 750 1000

Non-Emergency Engine Operating Hours per Year (hr/yr) 2800 2800 2800 2800 2800 2800 2800 2800

Capital Cost of HAP Control ($2009) $14,309 $14,931 $17,421 $19,911 $21,156 $26,136 $32,361 $38,586

Annual Cost of HAP Control ($2009/yr) $9,744 $9,863 $10,340 $10,817 $11,056 $12,010 $13,202 $14,395

Non-Emergency Engines - HAP

Uncontrolled HAP Emissions (Tons/yr) 0.0085 0.0170 0.0510 0.0851 0.1021 0.1701 0.2552 0.3402

HAP Emission Reductions (Tons/yr) 0.0065 0.0129 0.0388 0.0647 0.0777 0.1294 0.1942 0.2589

Total Annual Cost per Ton of HAP Removed ($/Ton) $1,505,529 $761,977 $266,275 $167,135 $142,350 $92,780 $67,995 $55,602

Non-Emergency Engines - CO

Uncontrolled CO Emissions (Tons/yr) 0.68 1.35 4.05 6.76 8.11 13.51 20.27 27.02

CO Emission Reductions (Tons/yr) 0.33 0.66 1.98 3.30 3.96 6.61 9.91 13.21

Total Annual Cost per Ton of CO Removed ($/Ton) $29,499 $14,930 $5,217 $3,275 $2,789 $1,818 $1,332 $1,089

Non-Emergency Engines - VOC

Uncontrolled VOC Emissions (Tons/yr) 0.04 0.09 0.26 0.44 0.53 0.88 1.31 1.75

VOC Emission Reductions (Tons/yr) 0.03 0.07 0.20 0.33 0.40 0.67 1.00 1.33

Total Annual Cost per Ton of VOC Removed ($/Ton) $292,675 $148,128 $51,764 $32,491 $27,673 $18,036 $13,218 $10,809

Non-Emergency Engines - NOx

Uncontrolled NOx Emissions (Tons/yr) 0.51 1.03 3.09 5.15 6.17 10.29 15.44 20.58

NOx Emission Reductions (Tons/yr) 0.50 1.00 3.00 5.00 6.00 10.00 15.00 20.00

Total Annual Cost per Ton of NOx Removed ($/Ton) $19,485 $9,862 $3,446 $2,163 $1,842 $1,201 $880 $720