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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2000 TRAVERWOOD ROAD

ANN ARBOR, MI 48105-2498

 OFFICE OF

AIR AND RADIATION

May 8, 2013

MEMORANDUM

SUBJECT: Potential Emissions Impact of the Transition Program for Equipment Manufacturers 

(TPEM) Amendments 

FROM: Angela Cullen, Mechanical Engineer

TO: Docket EPA-HQ-OAR-2012-0102

Background:

California Air Resources Board requested an analysis to quantify the potential emissions impact of the 

amendments to the Nonroad Compression Ignited (CI) Transition Program for Equipment Manufacturers 

(TPEM). The technical amendment rule makes the following three changes to the Nonroad CI TPEM:

1. Small volume allowance: Today every equipment manufacturer may use TPEM which allows up 

to 700 engines per engine line to meet the previous standard, with a limit of no more than 200 

per year. Today’s technical hardship exemption allows non-integrated manufacturers (with 

approval) up to an additional 400 engines (for a total of 1,100 units) and removes the annual 

limit, but the relief expires in 24-36 months for engines <560kW and limited allowance for <37 

kW. The technical amendment would remove the 1,100 per engine model limit, which becomes 

our discretion, and expands to all power categories. The amendment would also remove the 

small business criteria to apply for a small volume allowance.

2. Percent of production allowance: Today each equipment manufacturer may use TPEM for 80% 

of the production for an engine line for engines <560kW and limited allowance for <37 kW. 

Today’s hardship exemption allows non-integrated manufacturers (with approval) up to an 

additional 70% (for a total of 150%) allowance and a 24 month period for using up allowances

for engines <560kW and limited allowance for <37 kW. The technical amendment rule would 

remove the 70% cap, which now becomes our discretion, along with the 24 month expiration 

period.

3. FEL cap: Today’s engines may not exceed the FEL cap. The technical amendment would remove 

the FEL cap and allow manufacturers to use their banked credits and sell engines with emissions 
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above the FEL cap. We did not model the impact of this change because it is emission-neutral 

on a national basis.

Summary:

The technical amendments to TPEM could increase the national inventory in 2015 by as much as 45 

metric tons of PM emissions and 714 metric tons of NMHC+NOx. To put these numbers in perspective, 

the Nonroad Tier 4 program projected reductions of 48,297 metric tons of PM and 176,552 metric tons 

of NOx. The amendments would reduce the emissions reductions of the nonroad Tier 4 program by less 

than 0.1 to 0.4 percent.

Modeling Scenario:

We evaluated the potential emissions impact of the flexibilities that will become available through TPEM 

amendments using the following assumptions and modeling information.

1. Assumptions:

a. We assumed that there will be no additional flexibilities approved for exemption 

requests that have already been denied.

b. We evaluated each of the approved exemption requests to identify the potential for 

additional exemption requests based on the amendments.

c. We evaluated each of the pending requests to determine the additional exemptions 

which potentially could be approved if the exemption is approved. It is worth noting 

that we may not approve all of these requests.

2. Based on the assumptions above, Table 1 identifies the engines that have the potential to 

receive additional exemptions based on the amendments.

Table 1: Potential Additional Engine Exemptions

Company

Power 

Category MY

Additional 

Engines

A 19-56 kW 2014 409

B 19-56 kW 2014 2590

C 56-130 kW 2014 67

D

56-130 kW 2014 0

2015 136

130-560 kW 2014 259

2015 228

E 130-560 kW 2013 281

2014 281

F 130-560 kW

2013 150

2014 150

2015 150
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3. If the additional exemptions are approved, then these engines would be required to meet Tier 3 

standards (or Tier 2 standards for engines <56 kW) per 40 CFR 1039.625(e)(3) in lieu of the Tier 4 

final standards. For engines which cover more than one power category, the standard used in 

this analysis was assumed to be the average of the standard for each power category. Table 2

lists the standards with and without the exemption.

4. Table 3 includes the activity factors associated with the equipment that could use engines that 

may be exempted. The source classification code (SCC) was determined by identifying the 

closest match to the equipment considered for the exemption. The median power was 

calculated as the median power within the power range of engines. The load factor and annual 

activity factors were taken from EPA’s NONROAD model (see pages A4-A6 of 

http://www.epa.gov/otaq/models/nonrdmdl/nonrdmdl2010/420r10016.pdf).
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Table 2: Emissions Standards (g/kW-hr) for Modeling Exemptions

With Exemption Without Exemption

Company

Power 

Category

Emissions 

Level

NMHC 

+NOx NMHC NOx PM

Emissions 

Level NMHC +NOx NMHC NOx PM

A 19-56 kW Tier 2 6.1 -- -- 0.50 Tier 4 final 4.7 -- -- 0.03

B 19-56 kW Tier 2 6.1 -- -- 0.50 Tier 4 final 4.7 -- -- 0.03

C 56-130 kW Tier 3 4.35 -- -- 0.35 Tier 4 final -- 0.19 0.40 0.02

D

56-130 kW

Tier 3 4.35 -- -- 0.35 Tier 4 final -- 0.19 0.40 0.02

Tier 3 4.35 -- -- 0.35 Tier 4 final -- 0.19 0.40 0.02

130-560 

kW

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

E

130-560 

kW

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

F

130-560 

kW

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02

Tier 3 4.0 -- -- 0.20 Tier 4 final -- 0.19 0.40 0.02
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Table 3: Activity Information for Non-road Equipment

Activity and Load Fraction

Company

Power 

Category SCC SCC Description Products

Median 

Power (kW)

Load Factor 

(fraction of 

power)

Activity (hours 

per year)

A 19-56 kW 2270006025

Diesel Light Commercial 

Welders

welders 37.5 0.21 643

B 19-56 kW 2270006025

Diesel Light Commercial 

Welders

welders 37.5 0.21 643

C 56-130 kW 2270002081

Diesel Other Construction 

Equipment

excavator, 

compaction, skid steer

93 0.59 606

D

56-130 kW

2270002045 Diesel Cranes cranes

93 0.43 990

93 0.43 990

130-560 kW

345 0.43 990

345 0.43 990

E 130-560 kW 2270006015

Diesel Light Commercial 

Air Compressors

air compressor

345 0.43 815

345 0.43 815

F 130-560 kW 2270002081

Diesel Other Construction 

Equipment

off-road snow plows 

and dump trucks

345 0.59 606

345 0.59 606

345 0.59 606
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5. The potential annual impact of the technical amendments to the TPEM program nationally in 

2015 could be as high as 45 metric tons of PM emissions and 714 metric tons of NMHC+NOx. To 

put these numbers in perspective, the Tier 4 program projected reductions of 53,238 tons 

(48,297 metric tons) of PM and 194,615 tons (176,552 metric tons) of NOx (per Table 3.5-1b, 

Final Regulatory Impact Analysis, http://www.epa.gov/otaq/documents/nonroaddiesel/420r04007.pdf). Table 4 provides the annual national emissions impact of the provisions 

in 2015 for each of the companies.

Table 4: Potential Emissions Impact of Technical Amendments to TPEM

Annual Emissions Difference - 2015

Company

Power 

Category

PM 

(metric tons)

NMHC+NOx 

(metric tons)

A 19-56 kW 1 3

B 19-56 kW 6 18

C 56-130 kW 1 8

D

56-130 kW 0 0

2 20

130-560 kW 7 130

6 114

E 130-560 kW 6 116

6 116

F 130-560 kW

3 63

3 63

3 63