# E C 

# / R Incorporated Providing Environmental Technical Support Since 1989

501 Eastowne Drive, Suite 325  Chapel Hill, North Carolina 2751 4 Telephone: (919) 484 - 0222  Fax: (919) 484
- 0122 MEMORANDUM DATE: August 10 , 20 10 SUBJECT: MACT Floor and MACT Determination for Existing Stationary Non - Emergency

S I RI CE < 100 HP and Existing Stationary Emergency

S I RI CE Located at Major Sources and GACT for Existing Stat io nary S I RICE L ocated at Area Sources FROM: Tanya Parise , EC/R, Inc. TO: Melanie King , EPA OAQPS/SPPD/ESG 1.0 PURPOSE The purpose of this memorandum is to document the anal ys is of the maximum achievable control technology (MACT) floor and MACT for e xisting stationary non - emergency spark ignition (S I) reciprocating internal combustion engines (RICE) less than 100 horsepower (HP) and existing statio nary emergency

and black start S I engines located at major sources . The generall y achievable control tec hnology (GACT) determination for existing stationary S I RICE located at area sources of hazardous air pollutants (HAP) emissions that are subject to National Emission Standards for Hazardous Air Pollutants (NESHAP) is also presented in this memorandum. The anal ys is for exi sting stationary non - emergency

S I engines greater than or equal to 100 HP and less than or equal to 500 HP located at major sources of HAP emissions is presented in a separate memorandum titled “ MACT Floor and MACT Determination for Exi sting Stationary

SI RICE ≤500 HP L ocated at Major Sources , ” which is available in the rulemaking docket (EPA
- HQ - OAR - 2008 - 0708). 2.0 I NTRODUCTION EPA proposed NESHAP for existing stationary SI engines at area sources and existing stationary SI engines that are less than or equa l to 500 HP at major sources on March 5, 2009 (71 FR 9698) . The EPA previously promulgated NESHAP for existing stationary SI engines greater than 500 HP that are located at major sources, which were published on June 14, 2004 (69 FR 33474). The final NES HAP for existing stationary SIengines at area sources and existing stationary SI engines that are less than or equal to 500 HP at major sources will add requirements to 40 CFR part 63, subpart ZZZZ, for these engines.2

The regulation was developed foll owing criteria set forth under section 112 of the Clean Air Act (CAA). Section 112(d) of the CAA stipulates that EPA must promulgate emission standards that require the maximum degree of HAP reduction. According to 112(d)(3)(A) of the CAA, the emission s tandards for existing major sources must be no less stringent than the average emission limitation achieved b y the best performing 12 percent of existing sources for which the Administrator has emissions information
. For existing area sources, EPA has the option under 112(d)(5) of the CAA to promulgate emission standards or requirements , which provide for the use of generall y available control technologies ( GACT ) or management practices in order to reduce HAP emissions. Section 112 of the CAA outlines the statutory requirements for the EPA’s stationary source air toxics program. Section 112(k) of the CAA requires the development of standards for area sources which account for 90 percent of the emissions in urban areas of the 33 urban HAP listed in the Integrated Urban Air Toxics Strategy (UATS). These area source standards can require control levels which are equivalent to either MACT or GACT, as defined in the CAA under section 112(d)( 2 ) and (3) and section 112(d)(5), respectivel y. Section 112 of the CAA allows the EPA to establish subcategories among a group of sources. EPA has determined that the following subcategories are necessary to distinguish between existing stationary RI CE located at area source s :
 Non - emergency 2 - stroke lean burn (2SLB) stationary SI RI CE;  Non - emergency 4 - stroke lean burn (4SLB) stationary SI RI CE; o ≤500 HP o >500 HP  Non - emergency 4 - stroke rich burn (4SRB) stationary SI RI CE; o ≤500 HP o >500 HP  Non - emergency

landfill and digester gas stationary SIRICE; and  Emergency

stationary SIRI CE. EPA has discussed the appropriateness of distinguishing stationary engines by

fuel, mode of operation (emergency

versus non - emergency), burn ty pe (lean burn versus rich burn), and number of strokes (2
- stroke versus 4
- stroke) in a previous memoran dum. 1 The rationale provided in that memorandum supports establishing the subcategories listed above. In addition to the above subcategories established for existing stationary RICE located at area sources, this memorandum will also discuss the MACT fl oor and MACT for existing non
emergency

stationary

SI RI CE less than 100 HP that are located at major sources and existing emergency and black start stationary SI RICE that are located at major sources. EPA believes that previous determinations regardin g the appropriateness of using formaldeh yde levels in concentration (parts per million (ppm)) as surrogates for HAP for 4SRB stationary SI RICE, and carbon monoxide (CO) levels in concentration for all other stationary SI

1 Memorandum from Jennifer Snyder and Tanya Parise, Alpha
- Gamma Technologies, Inc. Subcategorization of Stationary Reciprocating Inte rnal Combustion Engines ≤500 HP. May 15, 2006. EPA - HQ - OAR - 2005 - 0030 - 0012.3

RI CE, are still valid. Consequent ly , EPA is finalizing formaldehyde standards for 4SRB RICE and CO standards for other SI RI CE to regulate HAP emissions. 3.0 MACT FLOOR AND MACT DETERMINATION Non - Emer gency

S I Engines <100 HP For stationary

S I engines less than 100 HP, EPA determined that it is not feasible to prescribe or enforce an emission standard because the application of measuring methodologies to this subcategory

of engines is not practicable due to technological and economic limitations. In order to measure the formaldehyde o r CO emissions from these engines in terms of volumetric concentration on a dry

basis and corrected to 15 percent oxygen ( O 2 ), the following test methods are required:

 EPA Method 1 or 1A for selection of sampling ports;  EPA Method 3, 3A, or 3B or ASTM Method D6522
- 00 (2005) for determining the O 2 concentration;  EPA Method 4 for measuring the moisture content;  EPA Method 10 or ASTM Method D6522
- 00 (2005) for measuring the carbon monoxide (CO) concentration; and  EPA Method 320 or 323 or ASTM Method D6348
- 03 for measuring the formaldeh yde concentration. The test methods require the sample point to be a certain distance between the engine and the exhaust. Because engines below 100 HP often have exhaust pipes with very small diameters and lengths, stack testin g using these methods could require a modification or extension of the exhaust pipe to accomplish the test. Furthermore, the cost of performing a stack test ranges from approximately $1,000
- $2 ,000 depending on the method used. The cumulative cost of test ing existing stationary

non - emergency

engines below 100 HP at major sources would be high . EPA estimates that there are more than 67,000 of these engines and to test them engines could cost as much as $135 million. Given the cost of the testing itself, the ph ys ical adjustments necessary to accomplish the test, and the particular circumstances pertaining to engines below 100 HP, EPA believe s that the application of measurement methodology to this class of engines is not practicable due to technological and economic limitations. Therefore, work practices are the MACT floor for existing stationary non - emergency

S I engines less than 100 HP. This is consistent with decisions made for existing stationary non - emergency

compression ignition (CI) engines less than 100 HP, which EPA finalized requirements for on March 3, 2010 (75 FR 9674). To determine the work practices, EPA reviewed information obtained from different manufacturers and operators of S I engines. The EPA has determined that the maximum achievabl e control, based on the work practices of the best controlled engines, is to maintain and replace the following stationary engine components: oil and oil filter, spark plugs , hoses, and belts. According to information received from manufacturers and operators of stationary engines, these parameters are the most appropriate to ensure proper operation for minimizing HAP emissions. Each of these work practices limit HAP emissions by allowing the engine to4

operate at peak efficiency. Changing the oil and oi l filter reduces the wear on the pistons and cylinders and limits the amount on worn metals that may be introduced to the exhaust stream. Maintaining efficient spark plugs reduces the potent ial for inefficient combustion and reduced efficiency , preventing higher emissions. Inspecting the belts and hoses ensures that the engines cooling and electrical s ys tems are operating, therefore eliminating the burning of oil and ensuring that the electrical sy stems are functioning as intended. Intervals for checking , inspecting and replacing the oil and oil filter, spark plugs , hoses, and belts vary

with engine makes and models, application, location, and other factors, therefore making it difficult to define specific maintenance intervals that would be represent the operation of the best controlled engines. However, EPA must promulgate specific requirements pursuant to section 112(d) of the CAA and the information indicates that there are commonalities in maintenance interval frequencies for the best controlled engi nes. Based on the information provided, EPA believes that the work practices below are what the best controlled existing stationary n on - e mergency S I e ngines less than 100 HP are currentl y doing and for that reason the MACT floor for these engines except 2 SL B engines is work practices as follows:

 Change oil and filter every 1, 44 0 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed be low and none of the condemning limits are exceeded;  Inspect spark plugs every 1, 44 0 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 1,44 0 hours of operation or annually , whichever co mes first, and replace as necessary
. The following work practices are what the best controlled stationary non - emergency

2SLB engines less than 100 HP are currentl y doing and is therefore the MACT floor:

 Change oil and filter every 4, 3 2 0 hours of operatio n or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 4, 3 2 0 hours o f operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 4, 3 2 0 hours of operation or annually , whichever comes first, and replace as necessary
. Two stroke lean burn engines have a longer maintenance i nterval than 4
- stroke engines because 2SLB engines do not have as much oil contamination and also operate at lower speeds and temperatures so spark plug s do not fire as frequently and fire at lower temperatures than 4
- s troke engines. Further rationale for longer maintenance intervals for 2SLB engines in general is discussed in the section on 2SLB engines in this memorandum. As discussed above, current maintenance procedures vary from engine to engine based on a number of factors including engine design , fuel, an d operating characteristics. Maintaining the oil however, is, one of the most important activities operators can perform to minimize emissions and to ensure proper operation and performance.5

In addition to following a set schedule for checki ng and replacing the oil, it is also common that the oil is monitored through an oil analy sis program where the oil is periodically sampled to determine oil quality . Based on the oil sample that is extracted, an oil anal ys is can be performed that can indi cate if it is time to replace the oil or if the existing oil has not reached condemning limits it can continue to be used. Based on the anal ys is a decision can be made whether to drain and replace the oil or if the oil change interval can be extended if t he properties of the oil are within acceptable limits. Appropriate parameters and condemning limits that would indicate oil degradation and the presence and quantity of contaminants varies. However, EPA has determined that the parameters that would most appropriatel y indicate the oil quality are the total acid number (TA N), visco sit y, and water content. The TA N is an indication of the acidity of the oil and the viscosity of the oil is a measure of how well the oil flows and these parameters are, along wi th water content, measures of the condition of the oil. If the following levels below as measured through an oil anal ys is program are exceeded, EPA has determined that an oil change must be performed:

 TAN increases b y more than 3.0 milligrams (mg) potass ium hydroxide per gram (KOH/g) from the TAN of the oil when new; or  viscosity

of the oil changes by

more than 20 percent from the viscosity of the oil when new; or  percent water content (b y volume) is greater than 0.5. No other regulatory

options beyond the MACT floor were identified as appropriate for exi sting stationary

non - emergency

S I engines below 100 HP. Therefore, MACT for HAP emissions is equivalent to the MACT floor for these engines. Emergency

S I Engines For existing stationary

S I emerg ency

engines located at major sources, EPA determined i t is not feasible to prescribe or enforce an emission standard because the application of measurement methodology to this class of engine is impracticable due to the technological and economic limitati ons . This is consistent with decisions made for existing stationary emergency CIengines, which EPA finalized requirements for on March 3 , 2010 (75 FR 9674). Emergency engines ty

pically onl y operate during emergencies or during periods of routine testing and maintenance. EPA determined that application of the emissions measurement methodologies during either of these periods is not practicable. Itis impracticable to test emissions from stationary S I emergency

engines during periods of routine testing and maintenance using the test procedures specified in the rule because it would increase the required number of hours of operation of the engine beyond the routinel y scheduled reliability testing and maintenance operation, thereb y increasing emissions. Wh ile emergency engines have periods of operation for scheduled maintenance and reliability testing, those periods are usuall y several hours shorter than the number of hours that would be required to run the necessary emissions tests under 40 CFR part 63, subpart ZZZZ. It is also impracticable to apply the testing methodologies required in this rule to test the stationary engines during periods of emergency operation because emergencies are unplanned events and implementation of the procedures specified in 4 0 CFR part 63, subpart ZZZZ require advance planning before tests are conducted. In an emergency ,6

the owner/operator does not have the advance planning time necessary to implement 40 CFR part 63, subpart ZZZZ. In addition, i t would be costly to test exis ting stationary S I emergency engines at major sources. EPA estimates that there are close to 1,600 existing stationary S I emergency

engines from 100 HP to 500 HP at major sources that are subject to this rulemaking. The cost for testing these engines cou ld be as high as $3 million
. For these reasons, work practices are appropriate and justified for this group of stationary engines because the application of measurement methodology is not practicable due to technological and economic limitations. Conse quently , work practices are the MACT floor for existing stationary

emergency S I engines located at major sources
. Again, in order t o determine the work practices for stationary emergency

engines at major sources , EPA reviewed information obtained from d ifferent manufacturers and operators of S I engines. For the same reasons as discussed above for existing stationary non - emergency SI engines less than 100 HP at major sources, EPA has determined that maximum achievable control, based on the work practices of the best controlled emergency engines, is to maintain and replace the following stationary engine components: oil and oil filter, spark plugs , hoses, and belts. EPA discussed above the effect that maintaining these parameters have on HAP emissions. As stated, intervals for checking, inspecting and replacing these components vary from engine to engine and determining specific maintenance intervals that would be represent the operation of the best controlled emergency engines is challenging
. However , EPA must promulgate specific requirements pursuant to section 112(d) of the CAA and the information indicates that there are commonalities in maintenance interval frequencies for the best controlled engines. Based on the information provided, EPA believ es that the below maintenance practices are what the best controlled existing stationary e mergency

S I e ngines are currentl y doing and for that reason, the MACT floor for these engines is maintenance practices as follows:

 Change oil and filter every 500 ho urs of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 1 , 000 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 500 hours of operation or annuall y, whichever comes first, and replace as necessary
. The changing of oil and the oil filter for stationary emergency engines is more frequent on an hourly basis than for non
- emergency engines because of the nature of operation of these engines, which is for standb y and intermittent use , and thus requires less hourl y use over the same period of time, and oil quality

is reduced over time even during periods when the engine is not used
. Emergency

S I engines also have the option to use an oil anal ys is program to determine if it is time to replace the oil or if the existing oil has not reached condemni ng limits it can continue to be used. The provisions of the oil anal ys is program are the same discussed above for n on emergency SIengines less than 100 HP .7

No other regulatory

options beyond the MACT floor were identified as appropriate for existing st ationary emergency S I engines at major sources. Because these engines are typically used only a few number of hours per year, the costs of emission control are not warranted when compared to the emission reductions that would be achieved. The cost per to n esti mates for stationary emergency

S I engines can be found in the memorandum entitled “ Cost per Ton of HAP R educed for Existing Stationary S I RICE ” in the rulemaking docket (EPA
- HQ - OAR - 2008 - 0708). Therefore, MACT for HAP emissions is equivalent to the M ACT floor for these engines. Black S tart E ngines B lack start engine s are used solely to start up combustion turbine s. They operate for very short durations and hav e the same issues as emergency S I engines based on their unique and limited operation. A ccording to information received during the public comment period, black start engines ty

picall y operate no more than 10 minutes at a time and onl y operate during emergencies or during periods of high demand (see for example EPA
- HQ - OAR - 2008 - 0708 - 0088 and 0 129). The short time of operation makes testing of black start engines using the required procedures impracticable. Therefore , work practices are the MACT floor for existing stationary black start engines located at major sources and are as follows:

 C hange oil and filter every 500 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exce eded;  Inspect spark plugs every 1 , 000 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 500 hours of operation or annuall y, whichever comes first, and replace as necessary
. As with st ationary

emergency

S I engines, n o other regulatory options beyond the MACT floor were identified as appropriate for existing stationary black start engines at major sources. The limited operating time also makes appl yi ng aftertreatment to black start engi nes not effective. In addition, these engines operate a few hours per ye ar, making further regulation of these engines economically impractical. Therefore, MACT is equivalent to the MACT floor for these engines. 4.0 REQUIREMENTS FOR ENGINES AT AREA SOUR CES Under CAA section 112(d)(5), EPA may elect to promulgate standards or requirements for area sources "which provide for the use of generall y available control technologies or management practices b y such sources to reduce emissions of hazardous air pol lutants." Additional information on generall y available control technologies or management practices (GACT) is found in the Senate report on the legislation (Senate report Number 101
- 228, December 20, 1989), which describes GACT as:8

. . . methods, practi ces and techniques which are commercially available and appropriate for application b y the sources in the category considering economic impacts and the technical capabilities of the firms to operate and maintain the emissions control sy stems. Determining what constitutes GACT involves considering the control technologies and management practices that are generally available to the area sources in the source category
. EPA also considers the standards applicable to major sources in the same industrial sect or to determine if the control technologies and management practices are transferable and generall y available to area sources. In appropriate circumstances, EPA may also consider technologies and practices at area and major sources in similar categories t o determine whether such technologies and practices could be considered generall y available for the area source category at issue. Finally , as EPA has already noted, in determining GACT for a particular area source category , EPA considers the costs and ec onomic impacts of available control technologies and management practices on that category
. For existing stationary

SI engines less than or equal to 500 HP , EPA is requiring management practices
. This determination is consistent with comments received on the proposed rule, as well as other information submitted to EPA post
- proposal. Comments EPA received on the proposed rule indicated that EPA had underestimated the cost of emission controls and overestimated how man y engines were already using these controls. Engine owners/operators have indicated that most of these smaller area source engines are not equipped with the control technologies required to meet these limits. For example, the American Petroleum Institute (API) said that the estimate of 4S RB engines currently equipped with add
- on controls that EPA used for the proposal (80 percent), was greatly overestimated. 2 The Gas Processors Association indicated that few, if an y, engines below 500 HP are currently equipped with add
- on controls. 3 Seve ral comments received on the proposed rule supported the use of management practices where EPA proposed that for certain engines, and further recommended that EPA establish management practices for other engines at area sources. Commenters indicated that the management practices EPA proposed are generally available, although they

did have comments on the maintenance intervals. More information on the management practice recommendations submitted by commenters is summarized in the response to comments docum ent for the final rule, available from the rulemaking docket. EPA reevaluated the cost impacts associated with establishing numeric emission limitations for these engines and determined that the cost impacts would be unreasonable for most engines gi ven th e expected emission impacts both with and without the expectation of use of emission control technologies. Specific costs for each engine type are provided in the sections that follow. Based on this information, EPA determined that management practice s for these stationary SI RICE less than or equal to 500 HP located at area sources of HAP are generally available and cost effective and these procedures will ensure that emissions are minimized and engines are properly

operated. EPA believes that requiring management practices instead of
2 Pages 80 - 81 of Comments on the Proposed Revisions to the National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines. Prepared by Amer ican Petroleum Institute. June 3, 2009. EPA - HQ - OAR - 2008 - 0708 - 0242.2. 3 Page 9 of Comments on the Proposed Revisions to the National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines. Submitted by Gas Processor s Association. June 2, 2009. EPA
HQ - OAR - 2008 - 0708 - 0112.1.9

specific emission limitations and/or control efficiency requirements on the majority of existing stationary SI engines at area sources alleviates concerns regarding costly and burdensome requirements for rural sources an d other area sources. Similarly , as discussed below, for engines above 500 HP , EPA determined, based on its reevaluat ion of the cost impacts associated with establishing numeric emission limitations for emergency

engines, black start engines, 2SLB engine s and l andfill and digester gas engines, that the cost impacts would be unreasonable for these engines given the expected emission impacts both with and without the expectation of use of emission control technologies. EPA also determined that management p ractices are generally available for these engines. Therefore, EPA is finalizing management practices for area source engines that are existing stationary

non - emergency 2SLB engines, existing stationary non - emergency 4SLB less than or equal to 500 HP, exi sting stationary non - emergency 4SRB engines less than or equal to 500 HP located at area sources of HAP, existing stationary non - emergency landfill and digester gas engines , and e xisting emergency stationary

SI engines. Finalizing management practices fo r most existing stationary

SIengines at area sources minimize s the burden of the final rule, particularl y on small businesses and individual owners and operators. For existing non
- emergency 4SRB engines greater than 500 HP at area sources and non emerg ency 4SLB stationary engines greater than 500 HP at area sources, EPA determined that it is appropriate to set numerical emission limits , which are expected to be met using emission control technologies. Additional discussion and the basis for EPA’s final determination are provided in the sections that follow. Non - Emergency

2SLB For existing stationary

non - emergency

2SLB engines, EPA determined that management practices are generally

available
. EPA looked at promulgating further requirements beyond mana gement practices for non
- emergency 2SLB engines at area sources. The first option EPA looked at was having a CO emission limit for these engines based on emission levels expected without using add
- on controls. EPA looked at the costs associated with this option, which include s the cost of performance testing, monitoring, recordkeeping and reporting. These costs are estimated to be more than $3,000 on an annual basis per engine
. On a cumulative basis, the ye arl y compliance cost would be close to $35 mill ion. However, a CO emission limit based on what a 2SLB engine could achieve without oxidation catal ys t would not result in any emissions reductions beyond what would occur with proper management practices
. EPA believes the costs associated with this opti on are unreasonable given there would be no emissions reductions achieved. The second option EPA looked at was going beyond management practices for non
emergency

2SLB engines at area sources by requiring emission limits based on levels expected using o xidation cataly st. Although add
- on controls are technicall y feasible for these engines located at area sources, EPA does not believe oxidation catal ys t is generally available for 2SLB engines. In addition, control costs are high and it is possible to ach ieve reasonable controls using management practices
. For example, the cost per ton of HAP removed associated with requiring10

oxidation catalyst control on a 250 HP engine is $224 ,000. For a 500 HP engine, the cost per ton of HAP removed is $ 128 ,000 and fo r a 1,000 HP e ngine, the cost is $8 0,000 per ton of HAP removed. Information on how EPA estimated the cost per ton for oxidation catal ys t on 2SLB engines and for specific costs for different size 2SLB engines, please refer to the memorandum “Cost per Ton of HAP Reduced for Existing Stationary SI RI CE,” available from the docket (EPA
- HQ - OAR - 2008 - 0708). EPA determined that it is not appropriate to go beyond management practices for existing non
- emergency 2SLB engines. Management practices represent what is generally available among such engines to reduce HAP, and the practices will ensure that emissions are minimized and engines are properly operated. Therefore , going beyond management practices is not justified and for existing stationary non - emergency

2S LB engines EPA is requiring management practices
. Regarding what management practices are required , EPA has determined that maintaining and replacing the following stationary engine components is generall y available management practice : oil and oil fil ter, spark plugs, hoses, and belts. In order to determine the specific intervals for management practices for stationary non - emergency

2SLB engines at area sources , EPA reviewed information obtained from different manufacturers and operators of S I engines
. Two stroke lean burn engines have a longer maintenance interval than 4
- stroke engines because 2SLB engines do not have combustion blow
- by gases entering the crankcase due to the engine configuration and therefore do not have as much oil contamination from the combustion blow
- by gases. The 2SLB engines also operate at lower speeds and temperatures than 4
- stroke engines, consequently

the spark plug does not fire as frequently and fires at lower temperatures than 4
- s troke engines. Therefore , 2SLB engine s should have longer maintenance practice intervals than 4
- stroke engines and consequently EPA has determined that the proper interval for stationary non - emergency

2SLB engines is every

4, 3 2 0 hours of engine operation or annually , whichever comes first. I ntervals for checking, inspecting and replacing the oil and oil filter, spark plugs , hoses and belts vary with engine makes and models, application, location, and other factors . This makes it difficult to define specific maintenance intervals that would b e representative of every

possible operating scenario. However, EPA must finalize specific management practices. Based on comments received on the proposed rule and more specificall y information received post
- proposal from Exterran, JW Power Company , and CSI(EJC) 4 indicates that a maintenance frequency of every 4,320 hours of operation is common practice and generall y available. This specific recommendation is supported by I NGAA and API. A maintenance interval of every 4,320 hours of engine usage will ensure that the components remain in proper condition and continue to perform the necessary functions to support proper engine operation, reduce HAP, and minimize emissions. Specifically , EPA is requiring the following management practices:

 Change oil an d filter every 4, 3 2 0 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 4, 3 2 0 hours of operation or annuall y, whichever comes first,
4 Memorandum from Rebecca Rentz, Bracewell and Giuliani to Melanie King, EPA. Spark Ignited (SI) Recommended Management Practices. January 27, 2010. EPA
- HQ - OAR - 2008 - 0708 - 0354.1.11

and replace as necessary ; and  Inspect all hoses and belts every 4, 3 2 0 hours of operation or annually , whichever comes first, and replace as necessary
. EPA has discussed above the effect that maintaining these parameters have on HAP emissions and believes that the above management practices will ensure that HAP emissions are minimized. EPA also determined that it would be appropriate to include the option to use an oil an al ys is program in the final rule. Non - Emergency 4SLB ≤5 00 HP For existing stationary

non - emergency

4SLB engines less than or equal to 500 HP located at area sources, EPA determined that management practices are generall y available
. EPA looked at promulgating further requirements beyond management practices for non
emergency

4SLB engines less than or equal to 500 HP at area sources. The first option EPA looked at was having a CO emission limit for these engines based on emission levels expected without the use of add
- on controls. EPA looked at the costs as sociated with this option, which include the cost of performance testing, monitoring, recordkeeping and reporting. These costs are estimated to be more than $3,000 on an annual basis per engine. On a cumulative basis, the ye arl y compliance cost would be close to $ 121 million. However, a CO emission limit based on what a 4SLB engine could achieve without oxidation catal ys t would not result in any emissions reductions beyond what would occur with proper management practices . EPA believes the costs associated with this option are unreasonable given there would be no emissions reductions achieved. The second option EPA looked at was going beyond management practices for non
emergency

4SLB engines less than or equal to 500 HP at area sources by requiring emission limits based on levels expected using oxidation cataly st. Again, add
- on controls are technicall y feasible for these engines located at area sources, but control costs are high when compared to the amount of reductions achieved. Information on the cost of control and the potential HAP reductions achieved with oxidation catalyst for different size 4SLB engines is presented in the memorandum “Cost per Ton of HAP Reduced for Existing Stationary SI RICE,” available from the docket (EPA
- HQ - OAR - 2008 - 07 08). R equiring emission limits on this segment of engines that would require the use of oxidation cataly st would result in a significant burden, especially on small businesses. For example, in the 250 HP to 500 HP size range, 40 percent of the population consists of agricultural engines, which are ty pically located at small businesses. For larger size engines, i.e., those above 500 HP, engines used for agricultural purposes represent onl y 14 percent of the total population. EPA does not believe the cost s of requiring aftertreatment are reasonable and therefore, going beyond management practices is not justified and GACT for existing stationary

non - emergency 4 SL B engines less than or equal to 500 HP is management practices
. Management practices represent what is generall y available am ong such engines to reduce HAP and the practices will ensure that emissions are minimized and engines are properly operated. EPA does not believe that management practices would be a substantial burden on owners and operator s such as homeowners and small entities.12

EPA has determined that for existing stationary non - emergency

4SLB engines less than or equal to 500 HP , the management practices shall be performed every 1,440 hours of engine operation or annually , whichever comes first, which reflects the management practices that are generall y available. Again, i ntervals for checking, inspecting and replacing the oil and oil filter, spark plugs , hoses and belts vary with different 4SLB engine makes and models, application, location, and other factors . This makes it difficult to define specific maintenance intervals that would be representative of every possible operating scenario. However, EPA must finalize specific management practices. Based on comments received on the proposed rule and more specificall y information received post
- proposal from Exterran, JW Power Company , and CSI (EJC), 3 which is supported by industry groups INGAA and API, indicates that a maintenance frequency of every 1,440 hours of operation is common practice and generally available. A maintenance interval of every 1,440 hours of engine usage will ensure that the components remain in proper condition and continue to perform the necessary functions to support proper engine operation, reduce HAP, and mi nimize emissions. Therefore , EPA is requiring the following management practices for existing stationary non - emergency 4SLB engines less than or equal to 500 HP at area sources :
 Change oil and filter every 1,440 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 1,440 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 1,440 hours of operation or annually , whichever comes first, and replace as necessary
. Non - Emergency

4SLB >5 00 HP For existing stationary

non - emergency

4SLB engines gr eater than 500 HP located at area sources , EPA determined that management practices are generally available . EPA looked at promulgating further requirements beyond management practices for non
- emergency 4SLB engines greater than 500 HP at area sources that are operated more than 24 hours per calendar ye ar . EPA considered having a CO emission limit for these engines based on emission levels expected without add
- on controls. Compliance costs are estimated to be more than $3,000 on an annual basis per engin e and cumulatively close to $28 million on a yearl y basis. Again, a CO emission limit based on what a 4SLB engine could achieve without oxidation catal ys t would not result in any

emissions reductions beyond what would occur using proper management practic es . EPA believes the costs associated with this option are unreasonable given there would be no emissions reductions achieved. The second option EPA considered was going beyond management practices for non
emergency

4SLB engines greater than 500 HP at area sources that are operated more than 24 hours per calendar year by requiring emission limits based on levels expected using oxidation catal ys t. EPA believes that oxidation cataly st is readily available and feasible for all existing stationary non - em ergency

4SLB engines above 500 HP generall y regardless of location . Further, EPA has determined that costs and economic impacts associated with implementing HAP
reducing technologies are reasonable and justified. For example, the cost per ton of HAP13

remo ved for a 750 HP engine is about $ 20 ,000 and is around $1 6 ,0 00 for a 1,000 HP engine. In formation on the specific add
- on control costs and cost per ton estimates can be found in the memorandum “Cost per Ton of HAP Reduced for Existing Stationary SI RICE,” available from the docket (EPA
- HQ - OAR - 2008 - 0708). Also, the controls that are expected to be used on these engines will have the co
- benefit of reducing volatile organic compounds ( VOC ) and CO emissions as well. The reductions estimated from installing c ontrols on non
- emergency 4SLB engines greater than 500 HP at area sources are 3,500 tons of HAP, 33,000 tons of CO, and 18,000 tons of VOC. Based on this, EPA believes it is appropriate to go beyond management controls for existing stationary non - emergenc y 4SLB engines greater than 500 HP at area sources. Therefore, EPA has determined that the final emission limits should be based on the use of oxidation cataly sts for existing stationary non - emergency

4SLB engines greater than 500 HP that are located at area sources . To determine the final emission limits , EPA looked at the CO emissions data from 4SLB engines less than or equal to 1,000 HP that are equipped with oxidation cataly st control. EPA has test results from 4 existing 4SLB engines with oxidatio n catalyst. Next, EPA followed the MACT floor approach using the upper prediction limit, which was discussed in a separate memorandum 5 , to establish the concentration. This resulted in a concentration of 47 ppm by volume, dry

basis (ppmvd) of CO at 15 p ercent O 2 . A summary of the test data that was used to set the concentration standard is available in Appendix B
- 2 of the memo titled “ MACT Floor and MACT Determination for Existing Stationary SI RI CE ≤500 HP Located at Major Sources
. ” Next, EPA looked at the test results 6 obtained during testing at Colorado State Universit y ( CSU ) for the 4SLB engines equipped with oxidation cataly st. The data from CSU indicate that oxidation catalysts on 4SLB engines are capable of reducing CO emissions by 93 percent or more. A control efficiency of 93 percent is also currentl y the CO percent reduction required for new and reconstructed stationary 4SLB engines greater than 500 HP and located at major sources that are equipped with aftertreatment under 40 CFR part 63, su bpart ZZZZ
. Consequently , for existing stationary

non - emergency

4SLB engines greater than 500 HP located at area sources that are operated more than 24 hours per calendar year , the final emission limit is 47 ppmvd of CO at 15 percent O 2 or a CO reduction of 93 percent. Non - Emergency

4SRB ≤500 HP For existing stationary

non - emergency

4SRB engines less than or equal to 500 HP located at area sources, EPA determined that management practices are appropriate for GACT. E PA looked at promulgating further requirements beyond mana gement practices for non
emergency

4SRB engines less than or equal to 500 HP at area sources. The first option EPA looked at was going beyond management practices by having a formaldehyde emission limit for these engines based on emission levels expected without add
- on controls. EPA looked at the costs associated with this option, which would include the cost of performance testing, monitoring, recordkeeping and reporting. These costs are estimated to be nearl y $4,000 on an annual basis per engine. On a cumulative basis, the yearl y compliance cost would be more than

5 Memorandum f

rom Tanya Parise, EC/R to Melanie King, EPA. MACT Floor and MACT Determination for Existing Stationary SI RICE ≤500 HP Located at Major Sources
. August 10 , 2010 . 6 Memorandum from Melanie Taylor and Jennifer Snyder, Alpha
- Gamma Technologies, Inc. to Sims Roy , EPA OAQPS ESD Combustion Group. January 7, 2004. EPA
- HQ - OAR - 2002 - 0059 - 0665.14

$123 million. However, a formaldeh yd e emission limit based on what a 4SRB engine could achieve without oxidation catal ys t would not result in any emissions reductions beyond what would occur with proper management practices . EPA believes the costs associated with this option are unreasonable given there would be no emissions reductions achieved. The second option considered b y EPA was going beyond management practices for non
emergency

4SRB engines less than or equal to 500 HP at area sources by requiring emission limits based on levels expected using add
- on control technology
. The applicable control technology

for reducing HAP is non - selective cataly tic reduction (NSCR) , which is technical ly feasible for these engines located at area sources
. However, control costs are high for these engines. For example , the cost per ton of HAP removed associated with requiring NSCR control on a 250 HP engine is $ 167 ,000. In formation on the cost per ton of HAP reduced with NSCR for different size 4SLB engines is presented in the memorandum “Cost per Ton of HAP Reduced for Existing Stationary

SI RICE,” available from the docket (EPA
- HQ - OAR - 2008 - 0708). R equiring emission limits on this group of engines ne cessitating the use of aftertreatment would result in a significant burden, especially on small businesses. As previously stated in this memorandum, in the 250 HP to 500 HP size range, 40 percent of the population consists of agricultural engines, which are t ypically located at small businesses. Although there are co
benefits with using NSCR on 4SRB engines, EPA does not believe that this co
- benefit outweighs the other considerations discussed above and does not justify going beyond management practices f

or existing non
- emergency 4SRB engines less than or equal to 500 HP at area sources. Management practices represent what is generall y available among such engines to reduce HAP, and the practices will ensure that emissions are minimized and engines are properl y operated. EPA determined that it is not appropriate to go beyond management practices for existing non
emergency

4 SRB engines less than or equal to 500 HP. EPA does not believe the costs of requiring aftertreatment are reasonable and theref ore, going beyond management practices is not justified and GACT for existing stationary non emergency

4SLB engines less than or equal to 500 HP is management practices. EPA does not believe that management practices would be a substantial burden on owner s and operators such as homeowners and small entities. EPA has determined that for stationary non - emergency

4SRB engines at or below 500 HP, it is appropriate for the management practices to be performed every 1,440 hours of engine operation or annually , whichever comes first, which reflects the management practices that are generall y available. As with 2SLB and 4SLB engines, intervals for checking, inspecting and replacing the oil and oil filter, spark plugs, hoses and belts vary between 4SRB engines b ased on different makes and models, application, location, and other factors. This makes it difficult to define specific maintenance intervals that would be representative of every possible operating scenario. However, EPA must finalize specific manageme nt practices. Based on comments received on the proposed rule and more specifically information received post
- proposal from Exterran, JW Power Company , and CSI(EJC), 3 which is supported b y industry groups INGAA and API, indicates that a maintenance frequ ency of every 1,440 hours of operation is common practice and generall y available. A maintenance interval of every 1,440 hours of engine usage will ensure that the components remain in proper condition and continue to perform the necessary functions to support proper engine operation, reduce HAP, and minimize emissions.15

Therefore, for existing stationary non - emergency

4SRB engines less than or equal to 500 HP at area sources , EPA is requiring the use of management practices as follows:

 Change oil and fi lter every 1,440 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspe ct spark plugs every 1,440 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 1,440 hours of operation or annually , whichever comes first, and replace as necessary
. Non - Emergency

4S RB >5 0 0 HP For existing stationary

non - emergency

4SRB engines greater than 500 HP located at area sources, EPA determined that management practices are generally available . EPA looked at promulgating further requirements beyond management practices for non
- eme rgency 4SLB engines greater than 500 HP at area sources that are operated more than 24 hours per calendar ye ar . EPA considered having a formaldehyde emission limit for these engines based on emission levels expected without add
- on controls. Compliance co sts are estimated to be almost $4,000 on an annual basis per engine and cumulativel y more than $28 million on a yearly basis. Again, a formaldeh yde emission limit based on what a 4 SRB engine could achieve without oxidation catal ys t would not result in any emissions reductions beyond what would occur with proper management practices . EPA believes the costs associated with this option are unreasonable given there would be no emissions reductions achieved. The second option EPA considered was going beyo nd management practices for non
emergency

4 SRB engines greater than 500 HP at area sources that are operated more than 24 hours per calendar year by requiring emission limits based on levels using aftertreatment
. Aftertreatment controls (NSCR) for existin g non - emergency 4SRB engines greater than 500 HP are readil y available and feasible regardless of location. Non
- selective cataly tic reduction , the technology

applicable to 4SRB engines for HAP reduction is generally available. Further, costs and economic impacts associated with implementing HAP
- reducing technologies are reasonable and justified
. T he cost per ton of HAP removed from a 750 HP engine is about $ 68 ,000 and $ 56,0 00 for a 1,000 HP engine. In formation on the specific add
- on control costs and co st per ton estimates can be found in the memorandum “Cost per Ton of HAP Reduced for Existing Stationary

SI RICE,” available from the docket (EPA
- HQ - OAR - 2008 - 0708). In addition, the controls that are expected to be used on these engines will have the co
- b enefit of reducing VOC, CO emissions and NO x emissions. For example, co
- benefits of NO x reductions can be achieved at a favorable cost effectiveness of less than $1,0 00/ton for a 750 HP engine and $720/ton for a 1,000 HP engine. EPA believes that this co - benefit adds to the justification for establishing emission limits based on the use of NSCR for these engines. The reductions estimated from installing controls on non
- emergency 4SRB engines greater than 500 HP at area sources are 1,200 tons of HAP, 64,0 00 tons of CO, 96,000 tons of NO x , and 6,400 tons of VOC. For these reasons, EPA believes it is appropriate to go beyond management practices for existing stationary non - emergency

4SRB engines greater than 500 HP at area sources. Therefore, EPA16

has deter mined that the final emission limits should be based on the use of NSCR for existing stationary non - emergency

4SRB engines greater than 500 HP that are located at area sources
. To determine the final emission limits for non
- emergency 4SRB engines great er than 5 00 HP located at area sources that are operated more than 24 hours per calendar year , EPA looked at the formaldeh yd e emissions from 51 uncontrolled 4SRB engines and determined the average uncontrolled formaldeh yde concentration . The average uncontrolled formaldehyde concentration was 11.3 ppmvd at 15 percent O 2 . Next, EPA applied a 76 percent formaldeh yd e control efficiency

to the uncontrolled formaldeh yde level
. The 76 percent formaldehyde control efficiency is based on test results 7 used to se t the final standards for stationary 4SRB engines greater than 500 HP at major sources and is consistent with the current requirement for these engines. As a result, the final emission limit for existing non
- emergency 4SRB engines greater than 5 00 HP is 2 .7 ppmvd formaldeh yde at 15 percent O 2 or a 76 percent formaldeh yde reduction
. Emergency

S I For existing stationary

emergency SI engines located at area sources, EPA believes that it is appropriate to set GACT to be the same requirements as is required for emergency engines at major sources because the same issues that were discussed above for stationary emergency

SI engines at major sources apply to emergency

SI engines at area sources. Again, this is consistent with how EPA treated existing stationary emergency CI engines in the requirements finalized on March 3, 2010 under 40 CFR part 63, subpart ZZZZ. There is no reason why the requirements for engines located at area sources pursuant to GACT should be different than those for engines located at maj or sources. The management practices are generally available and being located at an area source does not prevent the engine from being maintained appropriately and according to how engines at major sources are being maintained. Further, the management p ractices do not present an economic burden on area source engines . Therefore, GACT for existing stationary emergency

SI engines at area sources is the use of management practices as follows:

 Change oil and filter every 500 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 1,000 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 500 hours of operation or annuall y, whichever comes first, and replace as necessary
. As discussed above for major sources, these sources may utilize an oil analy sis program in order to extend the specified oil change requirement specified above. Black S tart E ngines

7 Memorandum from Melanie Taylor and Jennifer Snyder, Alpha
- Gamma Technologies, Inc. to Sims Roy, EPA OAQPS ESD Combustion Group. January 7, 2004. EPA
- HQ - OAR - 2002 - 0059 - 06 65.17

For existing stationary black start engines located at area sources, EPA believes that it is appropriate to set GACT to be the same requirement s as is required for black start engines at major sources because the same issues that were discussed above for stationary black start engines at major sources apply to these engines at area sources. There is no reason wh y the requirements for area source s pursuant to GACT should be different than those for black start engines at major sources. Therefore, GACT for existing stationary emergency SI engines at area sources is the use of management practices as follows:

 Change oil and filter every 500 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 1, 000 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 500 hours of operation or annuall y, whichever comes first, and replace as necessary
. Non - Emergency Landfill and Digester Gas For ex isting stationary

landfill and digester gas engines located at area sources, EPA determined that management practices are appropriate for GACT. EPA looked at going beyond management practices for non
- emergency landfill and digester gas engines at area sources. The first option EPA looked at was going beyond management practices by having a CO emission limit for these engines based on levels expected without add
- on controls. EPA looked at the costs associated with this option, which would include the cost of performance testing, monitoring, recordkeeping and reporting. These costs are estimated to be between $3,000 and $4,000 on an annual basis per engine, depending on the engine type. On a cumulative basis, the ye arl y compliance cost would be close to $ 2.5 million. However, a CO emission limit based on what landfill and digester gas engines could achieve without add
- on controls would not result in any emissions reductions beyond what would occur with proper management practices . EPA believes the costs associated with this option are unreasonable given there would be no emissions reductions achieved. The second option EPA looked at was going beyond management practices for non
emergency landfill and digester gas engines at area sources by requiring em ission limits based on levels expected using add
- on controls. However, a dd
- on controls are not technicall y feasible for these engines and it is possible to achieve reasonable controls using management practices. Therefore, going beyond management practic es is not justified and GACT for existing stationary non - emergency landfill and digester gas engines is management practices. M anagement practices represent what is generall y available among such engines to reduce HAP, and the practices will ensure that e missions are minimized and engines are properl y operated. Regarding what management practices are required , EPA has determined that maintaining and replacing the following stationary engine components is generall y available management practice : oil and oil filter, spark plugs, hoses, and belts. These same components must be maintained for the existing engines at major sources where MACT is work practices, and EPA believes these practices are transferable and generall y available to area sources. There18

is nothing preventing existing non
- emergency landfill and digester gas engines at areas from maintaining and replacing these engine components. To determine the specific intervals for management practices for stationary non emergency

landfill and digest er gas engines at area sources , EPA reviewed information obtained from different manufacturers and operators of S I , including operators of landfill and digester gas engines . Based on the information reviewed, it appeared that the management practices for landfill and digester gas engines are comparable to those of 4
- stroke engines in general. Ty pically , engines operating at landfills or that use digester gas fuels are either 4SLB or 4SRB. Also, based on information available to EPA, the majority of landf ill gas fired engines at 4SLB engines and digester gas engines are 4SRB. Therefore, management practices for landfill and digester gas engines are the same as for 4
- stroke engines. Specificall y, GACT for existing stationary non - emergency landfill and dig ester gas engines at area sources is the use of management practices as follows:

 Change oil and filter every 1,440 hours of operation or annuall y, whichever comes first, except that sources can extend the period for changing the oil if the oil is part of an oil anal ys is program as discussed below and none of the condemning limits are exceeded;  Inspect spark plugs every 1,440 hours of operation or annuall y, whichever comes first, and replace as necessary ; and  Inspect all hoses and belts every 1,440 hours of operation or annually , whichever comes first, and replace as necessary
.