
8950 Cal Center Drive, Suite 230
Sacramento, CA 95826
8950 Cal Center Drive, Suite 230
Sacramento, CA 95826



MEMORANDUM
TO:		Hether Krause and Johann Kuspert, MCAQD
FROM:	Mike Pring and Stephen Treimel, ERG

DATE:	August 28, 2017
SUBJECT:	Rule 324 (Stationary Internal Combustion (IC) Engines)  -  EPA Comment Response Support
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This memo documents the results of analysis conducted by Eastern Research Group, Inc. (ERG) to provide assistance to MCAQD in responding to EPA comments on the proposed Rule 324 (Stationary Internal Combustion (IC) Engines) revisions. This work was conducted under ERG's contract 16077-RFP with the MCQAD for Air Quality Rule Development Technical Support, Task Order (TO) 13.

1.0	BACKGROUND

Maricopa County was designated moderate nonattainment for the 2008 8-hour ozone standard on April 11, 2016. As part of the moderate classification, MCAQD has required Reasonably Available Control Technology (RACT) level of control for air pollution sources in Maricopa County. MCAQD prepared a Notice of Proposed Rulemaking for the proposed revisions to the ozone rules, including proposed changes to Rule 324  -  Stationary Internal Combustion (IC) Engines. EPA has provided MCAQD with comments on the proposed rule changes.

MCAQD requested ERG support to respond to EPA comments on the proposed Rule 324 revisions on three topic areas:

 NSPS Subparts IIII and JJJJ Limits Comparison to Rule 324;
 Engine Testing and Compliance Options; and
 Engine Testing Requirements under Other SIP Plans.

Each of these topics is discussed separately in Sections 2 thru 4 below.

In addition to rules specific to owning and operating engines in nonattainment areas, ERG identified several programs used by state and federal agencies to reduce emissions from engines. These include the Texas Emission Reduction Plan (TERP) program (https://www.tceq.texas.gov/airquality/terp), San Joaquin Valley's REMOVE II program (http://valleyair.org/General_info/Grant_Programs/GrantPrograms.htm), and EPA's Diesel Emissions Reduction Account (DERA) program (https://www.epa.gov/cleandiesel).

2.0	NSPS Subparts iiii and jjjj limits comparison to rule 324

MCAQD requested ERG support analyzing NSPS Subparts IIII and JJJJ under this TO as follows:

"In written comments provided on Maricopa County Rule 324 (revised November 2, 2016), the EPA states that it is insufficient to refer to limits in other regulations, such as 40 CFR 60 subparts IIII and JJJJ (because the rule must stand alone to be RACT). Due to the complexity of these subparts, the department has decided not to incorporate those limits into Rule 324. Our current strategy is to change the applicability dates in Tables 1 so that compression ignition (CI) engines manufactured on or after July 11, 2005 are subject to the same limits as CI engines manufactured on or after October 22, 2003 but prior to July 11, 2005. Similar changes would also be made to Table 2 (see modified tables below). The department has already determined that engines with displacement >= 30 liters per cylinder that were constructed prior to January 1, 2012 may not be able to comply with the limits in Table 1. The department would like to know if there are any other categories of engines that would comply with the requirements of subparts IIII or JJJJ but not comply with the limits in the following tables."
                                       
                                    TABLE 1
                         COMPRESSION-IGNITION ENGINES
MANUFACTURED OR MODIFIED
RATED BHP
ENGINE REQUIREMENTS 
Prior to October 22, 2003 
250-399
770 ppmdv or 10 g/bhp-hr. NOX or turbocharger with aftercooler/intercooler or 4-degree injection timing retard
Prior to October 22, 2003
400 plus
550 ppmdv or 7.2 g/bhp-hr. NOX or turbocharger with aftercooler/intercooler or 4-degree injection timing retard
On or after October 22, 2003 but prior to July 11, 2005
>250
530 ppmdv or 6.9 g/bhp-hr. NOX or turbocharger with aftercooler/intercooler or 4-degree injection timing retard; 1,000 ppmdv CO; 0.40 g/bhp-hr PM


                                    TABLE 2
                            SPARK-IGNITION ENGINES
                               LEAN-BURN ENGINES
MANUFACTURED OR MODIFIED
RATED BHP
OXIDES OF NITROGEN (NOX)
VOLATILE ORGANIC COMPOUND (VOC)
CARBON MONOXIDE (CO)
Prior to October 22, 2003
>250
280 ppmdv or 4.0 g/bhp-hr
800 ppmdv or 5.0 g/bhp-hr 
4,500 ppmdv 
On or after October 22, 2003 but prior to June 12, 2006
>250
110 ppmdv or 1.5 g/bhp-hr
800 ppmdv or 5.0 g/bhp-hr 
4,500 ppmdv 

                               RICH-BURN ENGINES
MANUFACTURED OR MODIFIED
RATED BHP
OXIDES OF NITROGEN (NOX)
VOLATILE ORGANIC COMPOUND (VOC)
CARBON MONOXIDE (CO)
Prior to October 22, 2003 
>250
280 ppmdv or 4.0 g/bhp-hr or three-way catalyst*
800 ppmdv or 5.0 g/bhp-hr or three-way catalyst*
4,500 ppmdv or three-way catalyst*
On or after October 22, 2003 but prior to June 12, 2006
>250
20 ppmdv or 0.30 g/bhp-hr or three-way catalyst*
800 ppmdv or 5.0 g/bhp-hr or three-way catalyst*
4,500 ppmdv or three-way catalyst*
*	The three-way catalyst shall provide a minimum of 80% control efficiency for NOX and CO for those engines fueled with natural gas, propane or gasoline. In addition, the three-way catalyst shall also provide a minimum of at least 50% control efficiency for VOC for those engines fueled by gasoline."

ERG Response:

As requested, ERG compared the limits in Tables 1 and 2 above for engine sizes greater than 250 BHP, but less than 30 liters per cylinder, to the requirements in NSPS Subparts IIII and JJJJ. ERG determined which categories of engines would comply with the requirements of Subparts IIII or JJJJ, but not comply with the limits in Tables 1 and 2. Under the NSPS Subparts IIII and JJJJ, owners and operators are only subject to the rule for certain categories of engines that are constructed, modified, or reconstructed after July 11, 2005 (Subpart IIII) or after June 12, 2006 (Subpart JJJJ). Therefore, any engines manufactured or modified "Prior to October 22, 2003" as listed in Tables 1 and 2 are not subject to the NSPS requirements and are excluded from this analysis.

For NSPS Subpart IIII, all engines that comply with the Subpart IIII standards will also comply with the Maricopa County Rule 324 standards (as shown in Table 1). There are no cases in which the Maricopa County Rule 324 standards are stricter than the applicable NSPS Subpart IIII standards for the applicable class of engines.

For NSPS Subpart JJJJ, there are certain categories of engines that comply with the applicable Subpart JJJJ standards that would not comply with the Maricopa County Rule 324 standards (as shown in Table 2). In these cases, the Maricopa County Rule 324 standards are stricter than the applicable NSPS Subpart JJJJ standards for the applicable class of engines. These engine categories are shown in Table 3.

Table 3. NSPS Subpart JJJJ/Maricopa County Rule 324 Standard Comparisons

                                Engine Category
                                     Size
                               Manufacture Date
                                  JJJJ Limit
                                   (g/hp-hr)
                                Rule 324 Limit
                                   (g/hp-hr)
                           Non-Emergency Natural Gas
                                100<=HP<500
                             on or after 7/1/2008
                                      1.0
                            0.3 (assume rich burn)
                           Non-Emergency Natural Gas
                                100<=HP<500
                             on or after 1/1/2011
                                      1.0
                            0.3 (assume rich burn)
                           Non-Emergency Natural Gas
                                   HP>=500
                             on or after 7/1/2010
                                      1.0
                            0.3 (assume rich burn)
          Landfill/Digester Gas (except lean burn 500<=HP<1,350)
                                   HP<500
                             on or after 7/1/2008
                                      3.0
                                      1.5
          Landfill/Digester Gas (except lean burn 500<=HP<1,350)
                                   HP>=500
                             on or after 1/1/2011
                                      2.0
                                      1.5
   Spark Ignition Landfill/Digester Gas (except lean burn 500<=HP<1,350)
                                   HP<500
                             on or after 7/1/2007
                                      3.0
                                      1.5
                        Landfill/Digester Gas Lean Burn
                               500<=HP<1,350
                             on or after 7/1/2008
                                      3.0
                                      1.5
                        Landfill/Digester Gas Lean Burn
                               500<=HP<1,350
                             on or after 1/1/2011
                                      2.0
                                      1.5
                                   Emergency
                                  >130 HP
                             on or after 1/1/2009
                                      2.0
                                      1.5

3.0 	engine testing and compliance options

MCAQD requested ERG support analyzing compliance requirements as follows:

"In written comments provided on Maricopa County Rule 324 (revised November 2, 2016), the EPA states that the testing schedule for non-emergency engines is irregular and constitutes unacceptable Director's discretion. The EPA recommends testing all applicable units every 2 years. The current version of the rule specifies the following methods listed below. Are there any EPA-approved alternative test methods for engines that may be more affordable and less burdensome than traditional stack test methods? Are there alternative approaches to compliance demonstration, such as exempting from testing all engines that are certified by the manufacturer to meet emissions standards that are at least as stringent as the standards in Rule 324?"


ERG Response:

ERG has identified several EPA-approved alternative test methods to those listed above as specified in NSPS Subparts IIII and JJJJ. EPA-approved alternative methods exist for:

 ALT-104 is an approved alternative to EPA Method 10 (see https://www3.epa.gov/ttn/emc/approalt/ALT104.pdf); and
 ALT-106 is an approved alternative to EPA Method 25A (see https://www3.epa.gov/ttn/emc/approalt/ALT106.pdf).

Information on the costs of using these alternative methods is not available. However, they are comparable in scope and design to the traditional EPA stack test Methods 10 and 25A and costs are expected to be similar.

As discussed in more detail below, the NSPS rules exempt engines that are certified by the manufacturer from testing requirements under certain conditions. In addition, EPA suggests the following alternative approaches for operators wishing to comply with the NSPS rules and avoid the expense of stack testing: 

 Comply by purchasing a CI engine certified by the manufacturer and EPA, and then installing, configuring, operating, and maintaining the engine per the manufacturer's instructions.
 Comply by purchasing a SI engine certified by the manufacturer to meet the emission limits, and then operating it according to manufacturer's instructions.
 Comply either by purchasing an SI engine that the manufacturer has voluntarily certified, or by conducting performance testing to demonstrate that the engine meets the applicable emission limits, and then operating it according to manufacturer's instructions. This method would require an initial stack test. This would likely require EPA approval of the test results in lieu of certification. 
 Purchase a CI engine with displacement < 30 liters per cylinder. 
 Purchase engines with no testing requirements (see below). 

EPA states that the testing portion of the compliance requirements for stationary engines are as follows: 

 Testing for existing non-emergency stationary engines, [CI engines > 100 HP at major source, CI > 300 HP at area source, and SI 100-500 HP at major source] would include an initial emission performance test, followed by subsequent performance testing every 8,760 hours of operation or 3 years for engines >500 hp (5 years if limited use).
 Testing for existing non-emergency stationary engines, [SI 4SRB >500 HP at major source] would include an initial emission performance test, followed by subsequent performance testing semiannually. The test frequency can be reduced to annual. Subsequent performance testing required for 4SRB engine complying with formaldehyde % reduction standard if engine is >=5000 HP.
 Testing for new non-emergency stationary engines, [SI 2SLB >500 HP at major source, SI 4SLB >250 HP at major source, SI 4SRB >500 HP at major source, and CI >500 HP at major source] would include an initial emission performance test, followed by subsequent performance testing semiannually. The test frequency can be reduced to annual. Subsequent performance testing required for 4SRB engine complying with formaldehyde % reduction standard if engine is >=5000 HP.
The following engines do not have a testing requirement:

       Existing emergency/black start engines [<100 HP at major source, <=500 HP at major source, and all existing emergency/black start engines at area source].
       Existing non-emergency engines [<100 HP at major source, CI <=300 HP at area source, SI <=500 HP at area source, SI 2SLB >500 HP at area source, SI LFG/DG >500 HP at area source, and SI 4SLB/4SRB >500 HP at area source used <=24 hours/year or in remote area].
   
Except for CI engines > 30 liters per cylinder (l/cyl) displacement, performance testing is not required under Subpart IIII and compliance is achieved by: 

 Purchasing a new engine that has been certified by EPA, and
 Installing, configuring, operating, and maintaining the engine per the manufacturer's instructions.

For certain SI engines manufactured on/after July 1, 2008, the engine manufacturer is required to certify that the engine meets emission limits. Owners or operators of these engines can comply by purchasing a certified engine and operating it according to manufacturer's instructions. These SI engine types include: 

 <= 25 HP,
 Gasoline engines >25 HP, and
 Rich burn LPG engines >25 HP.

For other SI engines, EPA made it optional for the manufacturer to certify that their engines meet the applicable emission limits. Owners or operators can comply either by purchasing an engine that the manufacturer has voluntarily certified, or by conducting performance testing to demonstrate that the engine meets the applicable emission limits.

4.0 	engine testing requirements under other sip plans

MCAQD requested ERG support analyzing engine testing requirements under other approved Ozone SIPs as follows:

 Are there other jurisdictions with approved Ozone SIPs that use the term Engine Family (or another term to describe a similar concept) to reduce the performance testing burden for facilities with multiple similar engines?
 Are there other jurisdictions with approved Ozone SIPs that exempt testing for engines certified by the manufacturer to emit NOx below the applicable regulatory limits and how do they define Engine Family?  If so, how long are engines exempt?
 Are there jurisdictions with approved Ozone SIPs that only require testing of non-emergency engines at major sources of NOx/VOC emissions?

ERG Response:

ERG addressed the questions regarding engine testing requirements in approved Ozone SIPs by evaluating approved state SIP rules for engines operating in California, Colorado, and Texas ozone nonattainment areas.

 ERG did not identify any other jurisdictions that use the term "Engine Family", or the concept of a group of identical or similar engines, to reduce performance testing requirements as proposed in Rule 324. Generally, the term "Engine Family" is used in regulatory language to group engines requiring testing by manufacturers (such as to demonstrate NSPS compliance by certifying specific makes and models of engines), and not by owners/operators.
ERG has seen a staggered testing approach used on a case-by-case basis in air quality permits for stationary sources with multiple identical units, but not codified in a state rule. Additional information on EPA's position on allowing a reduction of frequency in stack testing for identical units may be found in EPA's stack testing guidance, attached ("EPA Stack Testing Guidance.pdf"). An example of a recent EPA approval of a staggered testing schedule for multiple, identical engines under the conditions outlined in the Stack Testing Guidance document may be found in the attached file "Bio Town Ag.pdf".
Concerning the definition of "Engine Family", one suggestion would be to modify the definition to reference EPA's nonroad rules "Engine families" guidance:
      "Engine Family - A group of stationary RICE with similar design features such as fuel type, cooling medium, method of air aspiration, combustion chamber design including cylinder bore and stroke, exhaust after treatment (if any), method of fuel admission, and method of control, as defined in 40 CFR 89.116(b)." 
The existing Maricopa definition in Rule 324 does account for the characteristics of an engine family listed in 40 CFR 89.116(b). Note that the nonroad rule also uses the term "similar emission characteristics", which EPA appears to be questioning in Maricopa's rule. 
 ERG did not identify any other jurisdictions that exempt testing for engines certified by the manufacturer to emit NOx below the applicable regulatory limits. As described above in Section 3, the purchase of certified engines is one compliance approach suggested by EPA to reduce the stack testing burden on facilities subject to the engine NSPS requirements. That option is presented to demonstrate compliance specifically with the NSPS rules, and not state SIP or RACT rules, but it does appear to be a viable option for Maricopa to propose to EPA for rule 324.

 ERG did not identify any jurisdictions with approved Ozone SIPs that only require testing of non-emergency engines at major sources of NOx/VOC emissions.
Generally, the Ozone State SIP rules require testing of engines every two years, or every 8,760 hours of operation, whichever comes first. The Texas SIP rules for the Dallas-Fort Worth area require biennial testing, or every 15,000 hours, whichever comes first. The Sacramento rule requires testing ever five years, or every 8,760 hours of operation, whichever comes first.


