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July 29,2009

Bye-Mail (wayland.robertj@epa.gov)

and First Class Mail

Dr. Robert 1. Wayland

Leader, Energy Strategies Group

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

109 T.W. Alexander Drive (D243-01)

Research Triangle Park, NC 27709

Re: Supplement to EMA's Comments Regarding the

Proposed NESHAP For Stationary RICE

Dear Bob:

This letter is a follow-up to our meeting on June 22, 2009, during which we discussed the

significant concerns that the Engine Manufacturers Association ("EMA") has with respect to the

national emissions standards for hazardous air pollutants ("NESHAP") that U.S. EPA has

proposed for stationary reciprocating internal combustion engines ("RICE"). (See NPRM, 74 FR

9698, March 5, 2009.) In particular, this letter will reiterate the specific points that we discussed

regarding the Agency's authority under the Clean Air Act to adopt work/management practices

or operating requirements in lieu of specific HAP emission standards for: (i) stationary RICE

during periods of start-up and malfunction; (ii) emergency stationary RICE; and (iii) stationary

RICE less than 100hp. As you know, these issues, which are discussed in further detail below,

are likely to create fundamental and inherently unacceptable problems for the engine

manufacturing industry if EMA's recommendations are not incorporated into the final NESHAP

rule for the stationary RICE in question.

Stationary RICE Start-Up Operations and Malfunctions

During periods of RICE start-up, engine loads and exhaust temperatures are not high

enough to allow for the effective operation of catalyst-based exhaust treatment systems or

devices, and also are not representative of the engine loads, exhaust flows and temperature

profiles that RICE experience during their normal and intended operating conditions. Thus,

while the Agency is correct in its conclusion that emission standards based on the use of catalystbased emission reduction systems cannot be applied to periods of engine start-up, the Agency is

incorrect in its assumption that the emissions performance of an engine during start-up

operations can be made equivalent to the best-performing RICE, not equipped with catalystbased emission controls, but operating under stabilized steady-state conditions. Stabilized, fully

warmed-up, steady-state operating conditions yield engine loads, exhaust temperatures and

volumetric flows that are inherently different from start-up operations, and, more importantly,

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July 29, 2009

Dr. Robert J. Wayland

Page 2

that are inherently better suited to achieving lower emission levels than during transient, lowload, low-temperature, start-up operations. Thus, the two disparate types of operating conditions

(start-up v. stabilized operations) cannot be assumed to be capable of yielding the same type of

optimized emission levels. To the contrary, any such assumption would be unreasonable and

invalid as a basis for regulatory action.

This necessary conclusion is further supported by the fact that there are no specific,

verified and repeatable test procedures for measuring and quantifying HAP emissions during

periods ofRICE start-up operations. There is no start-up test cycle, no defined protocol for what

constitutes start-up, and no uniform and repeatable methodology for capturing and recording

start-up emission levels in-use in a manner that could be objectively assessed against a

benchmark standard for start-up emissions. Consequently, specific HAP standards for start-up

emissions are infeasible and unreasonable on these bases as well.

In light of the infeasibility of establishing HAP emission standards for engine start-up

periods that are equivalent to the standards applicable to warmed-up, normal steady-state engine

operations, the provisions of CAA section 112(h) clearly apply. Under section 112(h)(l), 42

U.S.C. §7412(h)(l), if it is not feasible to prescribe or enforce a HAP standard for certain

stationary sources, a work practice or operational standard may be established. Infeasibility for

such purposes specifically includes a situation where, as in the case of engine start-up operations,

"the application of [emission] measurement methodology... is not practicable." 42 U.S.C.

§7412(h)(2)(B). Significantly, the court in the Sierra Club case (No. 02-1135) specifically noted

the availability ofsection 112(h) as a means for dealing with start-up emissions.

Thus, in lieu of any specific HAP standard applicable to stationary RICE emissions

during start-up operations, EPA should adopt a work practice similar to the following:

RICE start-up operations, which constitute the time period

from engine ignition to the time when the catalyst temperature is

sufficient to enable effective catalyst operation, shall be

minimized. Start-up times shall not exceed 30 minutes or the

manufacturer's start-up recommendations, unless the Administrator

approves a longer time for certain engine classes or approves a

longer start-up time to address special conditions and requirements

(~, cold weather installations) in response to a petition from the

owner/operator. During initial commissioning, or after

modification (see 40 CFR §60.14) or reconstruction (see 40 CFR

§60.15) of the engine/equipment installation, additional time may

be required for the set-up procedures before normal catalyst

operation can be expected. Malfunctioning RICE shall be shut

down and repaired as soon as practicable based on the engine's

application and use.
July 29,2009

Dr. Robert J. Wayland

Page 3

With respect to the operation ofRICE during a malfunction, it makes no sense -- and thus

is inherently unreasonable -- to assume that a malfunctioning engine can and should perform in a

manner equivalent to the best performing RICE not equipped with catalyst-based emission

controls. The very essence of a malfunctioning engine is just that -- it is malfunctioning and so

not performing in an optimized manner for emissions purposes, or any other purpose for that

matter. Accordingly, it is quite simply irrational to require such a malfunctioning engine to meet

any sort of MACT-based standard. In that regard, and just as in the case of start-up operations,

there are no established and repeatable test cycles or procedures for measuring HAP emissions

from stationary RICE during periods of malfunctions. As a consequence, and again pursuant to

the flexibility provisions of CAA section 112(h), EPA should adopt a "work practice" to limit the

emissions of HAP during any period of RICE malfunction. In particular, and as noted above,

that work practice should require that any malfunctioning RICE be shut down and repaired as

quickly as possible with due regard for the use and application ofthe stationary RICE at issue.

Emergency CI Engines

Emergency stationary RICE generally operate less than 50 hours per year, and so have

"minimal" if any impact on ambient air quality. (See 74 FR at 9706.) Nonetheless, EPA is

proposing to apply a "MACT floor" HAP emission standard (of 40 ppmvd CO) to emergency

compression-ignition ("CI") engines rated from 50hp to 500hp and located at major sources, as

well as to emergency engines rated above 500 hp and located at area sources. The net effect of

such a MACT floor standard could lead to the forced replacement of up to 88% of the covered

emergency CI engines, since the standard is premised on the emissions levels achieved by the

best-performing 12% of the covered engines. Given the fact that there are approximately

700,000 emergency stationary RICE in the greater than 300hp category alone, that is a

thoroughly unreasonable result.

The minimal emissions impact of emergency RICE do not warrant costly emISSiOn

reduction requirements. It was for that very reason that EPA rejected a potential requirement for

add-on emission controls for emergency stationary engines. (See 74 FR at 9706.) Yet, in the

same breath, EPA is proposing standards that could necessitate the outright replacement of up to

88% of existing emergency RICE with new engines, the costs of which are far in excess of the

costs for add-on controls. Again, such a proposal is inherently unreasonable and costprohibitive.

Alternatives to specific MACT floor HAP standards are available for emergency

stationary RICE under the relevant provisions of the CAA. First, with respect to emergency

RICE located at area sources, section 112(d)(5) ofthe CAA, 42 U.S.c. § 7412(d)(5), specifically

authorizes EPA to promulgate management practices in lieu of specific HAP standards. Given

the wholly unacceptable cost ramifications of EPA's pending proposal, EPA should eschew

imposing a specific HAP standard on emergency engines, and instead should adopt a

management practice (just as was done in the NSPS rulemaking for emergency stationary CI
July 29, 2009

Dr. Robert J. Wayland

Page 4

RICE) generally limiting the non-emergency operation ofstationary emergency RICE to no more

than 100 hours per year. Such a management practice will ensure that the emissions impacts

from such engines remain minimal, while at the same time avoiding the enormous and

unreasonable cost burdens of EPA's current proposal.

Second, with respect to emergency RICE located at major sources, EPA should invoke

the flexibility provision of CAA section 112(h). As noted, that provision allows the Agency to

promulgate an operational standard, such as an annual hours of use limit, when it is not feasible

to prescribe or enforce a specific HAP emission standard. For stationary emergency CI engines,

advanced emission control systems are not feasible because, unless there is an actual and

sustained emergency (when far more than short-term air quality is at stake), those engines do not

operate long enough during their periodic maintenance and service testing (the only other times

such engines operate) to reach sufficiently high and stabilized temperature and load points to

optimize the performance capabilities of emission control systems (including, but not limited to,

add-on controls). As a result, it is not feasible to utilize "a conveyance designed and constructed

to capture such [HAP] pollutants" in an effective manner for emergency CI engines. Pursuant to

CAA section 112(h)(2)(A), such circumstances can constitute the type of practical "infeasibility"

sufficient to warrant the promulgation of an operational standard (i.e., limiting the nonemergency operation of emergency RICE to 100 hours per year) in lieu of a specific HAP

standard.

Accordingly, in light of the foregoing, EPA should adopt an operational standard in lieu

of any specific MACT floor standard for stationary emergency CI RICE. As in the NSPS

rulemaking, that operational standard generally should limit the non-emergency operation of

such engines to no more than 100 hours per year.

Non-Emergency RICE Less Than lOOhp

The same rationale that applies to emergency CI RICE also applies to non-emergency

stationary CI RICE less than 100 hp. Those engines likewise contribute minimal quantities of

HAP emissions and it is not cost-effective to require any type of add-on controls for such small

engines. Accordingly, with respect to engines less than 100 hp located at area sources, EPA

should adopt management practices under CAA section 112(d)(5) to control the emissions from

such very small stationary RICE. Those management practices could include requirements to

follow the engine manufacturers' maintenance instructions and to use ultra-low sulfur diesel fuel.

With respect to engines under 100hp located at major sources, CAA section 112(h) similarly

provides the Agency with sufficient discretion to adopt work practices in lieu ofspecific MACTbased standards.

EMA appreciates the opportunity to submit these follow-up comments regarding certain

of the concerns expressed during our most recent meeting with Agency, and we thank you in
July 29,2009

Dr. Robert J. Wayland

Page 5

advance for your careful consideration of these very important matters. In the event that you

have any questions regarding EMA's concerns, please do not hesitate to contact me.

TAF:kj

cc: Penny Lassiter (lassiter.penny@epa.gov)

Melanie King (king.melanie@epa.gov)

Michael Horowitz (horowitz.michae1@epa.gov)

EMA Stationary Engine Committee

EMADOCS: 35949.1