## INGAA Emissions Data Collection:

Carbon Monoxide Emissions from Natural Gas-Fired Two-Stroke Cycle and Four-Stroke Cycle Lean Burn Reciprocating Internal Combustion Engines

Emissions Data for Reciprocating Internal Combustio n Engine National Emission Standard for Hazardous Air Pollut ants (RICE NESHAP): 2010 Amendments for Existing Engine s

Technical Report: CO Emissions Data for Lean Burn Engines and MACT Floor Analysis

Prepared for:

Interstate Natural Gas Association of America 10 G Street NE, Suite 700 Washington, DC 20002

Prepared by:

Innovative Environmental Solutions, Inc.

P.O. Box 177 Cary, IL 60013

April 2010Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

i TABLE OF CONTENTS

1. Project Objectives and Data Sources ................

................................................... ....................... 1

2. MACT Floor Determination: Basis and Analysis Approa ch ................................................. ..... 3

2.1. Identifying Best Performing Units..................

................................................... .................. 4

2.2. MACT Floor Variability .............................

................................................... ...................... 7

3. Data Summary: Four-Stroke Cycle Lean Burn Engines ..

................................................... ........ 9

3.1. Comparison with EPA 4SLB Data......................

................................................... .............. 12

3.2. Variability and Factors that Influence 4SLB CO Emis sions .............................................. . 12

4. Data Summary: Two-Stroke Cycle Lean Burn Engines ...

................................................... ....... 15

4.1. Overview of MACT Floor Engines and 2SLB Engine Subc ategories ................................ 20

4.2. Emissions Variability Assessment ..................

................................................... ................. 22

4.3. Discussion of CSU 2SLB Engine Data and NOx – CO Tra deoff........................................ 23

5. Conclusions and Recommendations....................

................................................... ..................... 28
Appendices .........................................

................................................... ............................................ 30
Appendix A: 4-stroke Lean Burn Engine Data
Appendix B: 2-stroke Lean Burn Engine DataTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

1 1.0 Project Objectives and Data Sources
A rule to amend the Reciprocating Internal Combusti on Engines (RICE) National Emission Standards for Hazardous Air Pollutants (NE SHAP) was proposed on March 5, 2009. The proposed rule addresses standards for ex isting major source engines 500 horsepower (hp) and smaller and existing area sourc e engines of all sizes. The Interstate Natural Gas Association of America (INGAA) is a tra de association of the interstate natural gas transmission industry, and INGAA member companies operate stationary natural gas-fired spark ignition internal combustio n (IC) engines. These engines are installed at compressor stations along the pipeline s to transport natural gas to residential, commercial, industrial and electric utility custome rs. INGAA submitted comments on the proposed rule on June 3, 2009, and a primary co ncern was the basis of proposed emission standards for gas-fired IC engines. This concern was primarily due to deficiencies in the data used to establish emission standards for a regulation that will impact thousands of engines. These deficiencies in clude both a lack of emissions data and data quality issues. INGAA’s concerns are deta iled in its comments, which are available in the rule docket (Docket Document No. E PA-HQ-OAR-2008-0708-0155).

The proposed rule addresses existing engines; thus, emissions data for existing equipment are of interest. INGAA conducted an emissions data collection effort, gathering data from its members to supplement the emissions data a vailable for the rulemaking. The proposed rule includes carbon monoxide (CO) emissio n standards for lean burn engines, with CO emissions a surrogate for HAP emissions. F ormaldehyde emission standards were proposed for rich burn engines. CO testing ha s been completed for many engines, typically associated with NOx compliance tests. Th us, it was anticipated that CO data would be available for lean burn engine categories. Formaldehyde testing is relatively rare, but formaldehyde data were also solicited. T he objective of this effort was to:

• Assess the availability of emissions data for the t hree primary natural gas-fired IC engine subcategories: 2-stroke lean burn (2SLB), 4 -stroke lean burn (4SLB), and 4- stroke rich burn (4SRB) engines;

• Collect available emissions data, including CO data for 2SLB and 4SLB engines and formaldehyde data for 4SRB engines;

• Compile and organize the data into a report for tra nsmittal to EPA; and,

• Review and analyze the data to assess implications for the emission standard, including the basis for the minimum standard requir ed under the Clean Air Act. This minimum standard is referred to as the “MACT floor” . The Clean Air Act requires that the emission standard for existing units be ba sed on the average emission limitation achieved by the best performing 12% of e ngines in a subcategory. In recent Court cases, it has been clearly delineated that NESHAP standards can take into account emissions variability, which considers emissions at adverse operating conditions that are reasonably likely to recur. Th us, INGAA analysis considered the MACT floor and emissions variability. As discussed in Sections 3, 4, and 5, this review concludes emissions variability warrants CO standards over 370 ppmv (at 15% O 2 ) for both 4SLB and 2SLB engine subcategories and s pecific recommendations are discussed in those sections.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

2 Since CO data are relatively common, INGAA members provided data summaries for review and compilation. A significant amount of CO data were collected for lean burn engines, especially 2SLB engines, which are the mos t common units used in gas transmission. Formaldehyde data for 4SRB engines w ere generally not available. Since formaldehyde data are sparse, INGAA understands tha t other efforts are underway to test 4SRB engines and recommends that EPA consider those data for establishing 4SRB standards.

This report presents the results of the INGAA emiss ions data collection effort and provides CO emissions data for 2SLB and 4SLB engine s. A summary of the engine types and collected data presented in this report i ncludes:

• CO emissions test data from over 400 natural gas-fi red engines, including 85 fourstroke lean burn engines and 325 two-stroke lean bu rn engines;

• Over 3,000 test runs and 1,000 individual tests (i. e., 3 test runs are common for many compliance tests);

• Most engines are larger than 500 hp, consistent wit h the population of existing gas transmission engines, but test data are included fo r engines 500 hp and smaller.

Engines with multiple tests and multiple test condi tions across the operating envelope are of special interest for assessing emission variabil ity. Data review indicates that many engines had four or fewer test runs (i.e., a single “test” often includes 3 or 4 “test runs” at a single operating condition). The number of test runs per engine varied from one to over fifty. Based on Court decisions, EPA’s approach fo r standard development assesses variability on emissions from the best performing 1 2% of sources (i.e., “MACT floor units”). Thus, it is informative if MACT floor uni ts have emissions data at multiple test conditions and across the operating range.

In addition, INGAA and its members have actively en gaged in other emissions testing programs for over 15 years. These include projects at the Colorado State University (CSU) Engines and Energy Conversion Laboratory (EEC L) engine testbed, which includes a 2SLB engine common in gas transmission. For example, in 1999 EPA funded testing on the CSU 2SLB engine to develop data for the original RICE MACT standard, and gas transmission stakeholders participated in t hat effort through the Pipeline Research Committee International (PRCI) and Gas Res earch Institute (GRI). Compared to engines in field operations where tests are pred ominantly high load compliance tests, this 2SLB engine provides data over a broader range of standard operating conditions. As noted in the June 2009 INGAA comments, these tes ts may provide data to assess emissions variability. Thus, data from the CSU 2SL B engine are included in this report, and the test data from the 1999 EPA study are suppl emented with additional CSU data. EPA also funded 4SLB engine tests at CSU. Unfortun ately, that engine was sited at the test bed for only a sort time and additional data b eyond the EPA program are not available for the 4SLB engine. The EPA test data a re already in the rule docket. The CSU 2SLB data are discussed in Section 4. In addit ion, 2SLB data from recent testing completed by compression service providers is inclu ded in this report, as discussed in Section 4.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

3 While this is primarily a “data report”, the docume nt includes analysis and discussion that provide a technical summary of the collected data. In addition to this introduction, Section 2 of this report discusses the process asso ciated with the “MACT floor” analysis based on INGAA’s understanding of Clean Air Act req uirements and recent Court cases. This “process” includes identifying the best perfor ming 12% of engines and assessing variability from that engine population. Section 3 presents summary data and tables for the 4SLB engine subcategory. Section 4 presents su mmary data and tables for the 2SLB engine subcategory. Section 5 summarizes the resul ts and conclusions. Detailed data and quality assurance information are provided in a ppendices. Appendix A provides data tables for the 4SLB engines and Appendix B provides data tables for the 2SLB engines. The table format includes a unique engine identifie r, test run identifier, engine information (e.g., make, model, type), test informa tion (e.g., test date, engine load), emissions data, and averages of multi-run tests if more than one test-run is completed at a single operating condition (e.g., compliance tests) . In addition to these appendices, supplementary information such as test reports and test validation documentation for engines that populate the MACT floor will be provid ed to EPA separately.

2.0 MACT Floor Determination: Basis and Analysis Approa ch
Appendices A and B provide the data from the INGAA collation of reciprocating engine emission tests. Appendix A presents 4SLB data and Appendix B presents 2SLB data. For tests (e.g., compliance tests) with multiple te st runs (typically three runs) at the same engine operating condition, the average of the runs is presented and each test run is shown as a separate row. These data are summarized in Sections 3 and 4, and INGAA includes analysis and discussion of our perspective of this dataset, including identification of the “MACT floor” and consideratio n of variability. This section discusses the basis for the analysis in this report

.
Section 112(d)(3)(A) of the Clean Air Act requires that emission standards for existing engines be based on “the average emission limitatio n achieved by the best performing 12% of the existing sources...”. This emission level is typically referred to as the “MACT floor”. As discussed below, decisions from t he D.C. Circuit Court support the consideration of variability in establishing the em ission standard. The analysis and discussion in Sections 3 and 4 focus on the engines that comprise the MACT floor with data for all engines in the Appendices. The method ology for defining the MACT floor engines is discussed below.

For this analysis, INGAA considered the Clean Air A ct, Court decisions regarding the basis for determining Section 112(d) emission stand ards, EPA’s analysis for existing compression ignition engines in the March 3, 2010 RICE NESHAP amendments, and recent EPA MACT floor analysis from other NESHAP ru les. In addition, this analysis is supplemented by INGAA’s understanding of reciprocat ing engine emissions, the inherent variability in emissions from natural gas-fired rec iprocating engines, and operating conditions such as load that can affect lean burn e ngine CO emissions.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

4 For lean burn gas-fired engines, the proposed rule establishes CO as a surrogate for HAP emissions such as formaldehyde. In discussions wit h INGAA, EPA has indicated that it is acceptable to complete the MACT floor analysis b ased on CO emissions data, and companion HAP data (e.g., formaldehyde) are not nec essary. Since CO measurement is common in compliance tests, available test results offer considerable data and the INGAA data collection focused on CO emissions data. Since formaldehyde emissions testing typically has not been required and formald ehyde is more difficult to measure than CO, it was expected that very little formaldeh yde data would be available from previously conducted tests. This was verified in t he data collection effort.

INGAA understands that EPA will complete a MACT flo or analysis based on available data, including the data in this report. INGAA is compelled to provide its perspective of the MACT floor analysis and consideration of variab ility based on Clean Air Act requirements and recent Court decisions. Because t here are many existing reciprocating internal combustion engines and it is not feasible to have a detailed understanding of emissions from all engines, any available dataset w ill have inherent limitations or deficiencies and those limitations need to be consi dered in the analysis. For example, although this report provides considerable data fro m many engines, there are limitations that could result in an unreasonable outcome depend ing upon the technical analysis of the data. INGAA compiled data from previous tests and some limitations include:

• The CO data are primarily from previous compliance emission tests. The CO emissions data were not collected as part of a comp rehensive testing project with specific objectives to understand either “best perf orming” CO levels or emission variability. Thus, the dataset characteristics str ongly reflect compliance test criteria;

• Almost all the test data are from compliance tests such as annual performance tests or quarterly portable analyzer tests. These tests are typically driven by NOx concerns that require high load tests. The proposed rule req uires compliance at all operating conditions including low load, and it is commonly understood that lean burn engine CO emissions increase at lower load. CO test data at low load are sparse; thus, the collective data set significantly under-represents low load operating conditions and bias the data, on average, towards high load condit ions with lower characteristic CO emissions and higher NOx emissions.

• The number of tests for any particular engine varie s from one test , which often includes three test runs at one operating condition , to numerous tests conducted over a period of years and/or at various operating conditi ons. As discussed below, this influences the preferred approach for identifying b est performing engines when comparing emissions in the dataset – i.e., which em issions data are used to determine the best performing engines when considering engine s with multiple tests.

2.1 Identifying Best Performing Units
The March 2009 proposed rule established the “MACT floor” technology as an uncontrolled engine – i.e., no add on HAP controls are applied. INGAA supports that conclusion, and the analysis for RICE subcategories is not complicated by multiple HAP or CO control technologies within the INGAA data po pulation. The INGAA COTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

5 emissions data are from engines that do not include CO controls – i.e., do not include an oxidation catalyst.

INGAA understands that EPA plans to focus on the be st performing units (i.e., data from the best performing 12%) when assessing variability . However, different approaches can be considered, and have been used by EPA in NESHAP rules, to identify the best performing units in the dataset. Since the engines in this report include some engines with single or very few tests and other engines wit h multiple tests at various times and/or operating conditions, the basis of this comparison is important.

In addition, some tests include multiple test runs at a single operating condition – i.e., three tests runs that are averaged for a compliance test. Other tests in the data set are single runs. The analysis approach needs to identi fy how data will be treated for tests with multiple test runs completed at a single opera ting condition.

Based on docket documents, INGAA understands that f or the March 2010 compression ignition NESHAP amendments, when multiple test runs are available for a single test condition , such as three “high load” test runs for a complia nce test, EPA used the average of the multiple runs (i.e. the test average) when c omparing emissions data between engines to identify the best performing 12%. If on ly a single run is available at a particular test condition (e.g., prevalent for test data from EPA-sponsored and other tests at the Colorado State University engine test bed), that single test result is used for the inter-engine comparison to identify the best perfor ming 12%. INGAA uses this same approach in the Section 3 and Section 4 discussion.

The next step is to consider how to evaluate engine s and compare data between engines when some engines have multiple tests. This compar ison “ranks” the engines and identifies the best performing 12% of the engine po pulation. In the INGAA data set, engines with multiple tests include engines tested at different times (e.g., annual or quarterly compliance tests over a period of time), and, to a lesser extent, engines tested at multiple operating conditions (e.g., multiple loads ). As described below, INGAA recommends that for engines with multiple CO emissi on tests, the lowest or best performing CO emissions from each engine should be used for engine-to-engi ne comparisons to identify the best performing 12%. T his approach bases the comparison on the best performance for each individual engine, and provides the best assurance that tests completed at similar operating conditions (e. g., tests at high load) are compared when defining the engines that comprise the top 12%

.
To further explain, consider an alternative approac h where the highest CO emissions are used for engine-to-engine comparisons when an engin e has multiple tests. Since the CO data compiled from INGAA members are typically from compliance tests, high load is the norm. Thus, for engines in the data set with a single test, a high load test with lower characteristic CO emissions is most likely. Altern atively, an engine with multiple tests may have data over a broader array of conditions, i ncluding changes to load or other parameters that can impact CO such as the air to fu el ratio (i.e., AFR which reflects the amount of excess combustion air) or ambient conditi ons (e.g., summer versus winterTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

6 tests). The prevalence of compliance test data als o ensures that multi-test engines very likely include data at full load with lower charact eristic CO emissions.

If the top 12% is selected based on comparing the h ighest CO from multi-test engines, it is likely that an operating condition with higher c haracteristic CO emissions (e.g., lower load and/or higher AFR) from the multi-test engine would be compared to a full load test with lower characteristic CO emissions for the sing le-test engine. This is an inequitable comparison which will result in multi-test engines being precluded from or limited in the engine population that comprises the best performin g 12%. In addition, this approach prevents the comparison of CO emissions at common operating conditions (e.g., high load and nominal AFR) for the multi-test versus sin gle test engines, and also prevents consideration of operating conditions that reflect “best performance” for multi-test engines.

Based on this understanding of the emissions datase t and associated test conditions, INGAA believes that the most logical and technicall y preferred approach is to compare engine-to-engine data under similar operating condi tions where feasible. Such a comparison has a higher probability of identifying the better performing engines. For example, comparing CO emissions from two engines at high load provides an indication of the better performer. However, comparing high l oad emissions (with lower characteristic CO) from one engine with low load em issions (with higher characteristic CO) from another engine does not provide a reasonab le basis for assessing which engine is the better performer because there is a discrepa ncy in load, a key operating parameter that is known to impact lean burn engine CO emissio ns.

Engine emission characteristics also support the co mmon operating condition comparison that is best achieved by comparing lowest emissions from multi-test engines. For example, for lean burn reciprocating engines, it is generally expected that CO emissions are more variable across the range of typical engin e conditions (e.g., load and AFR) on an individual engine than the variability that would b e reflected by comparing multiple similar engines at a common high load operating con dition. If all engines in the dataset were tested under a similar range of operating cond itions and had a similar number of test points, this issue would be less compelling. Howev er, for the data provided in this report, where the number of tests per engine varies from a single test on many engines to more than ten tests on other engines, this analytical ap proach is important not only for defining best performers, but also for providing the ability to consider data from multiple tests to better understand emissions variability.

While the alternative approach (i.e., identifying M ACT floor engines based on highest CO emissions) is not detailed in this report, INGAA review of the dataset confirms the concerns expressed here: sorting the data based on the best performing or lowest CO emissions for multi-test engines results in many en gines with multiple tests in the MACT floor (as shown in Sections 3 and 4); in contrast, an alternative that sorts the engines based on maximum emissions results in nearly all of the MACT floor engines being single test engines (i.e., CO based on one test run or one, three run test at a single operating condition). The latter outcome hinders t he ability to assess emissionsTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

7 variability for the best performing 12% of engines. It also fails to identify the engines with the best CO emissions performance.

Thus, INGAA strongly recommends that the “best perf orming” engines within a subcategory be based on selecting the lowest CO tes t from multi-test engines for comparison with other engines. INGAA believes that this approach is consistent with the Clean Air Act and has the most technical merit for equitably comparing engine emissions performance and identifying best performing engines . In addition, since this approach will limit the likelihood that multi-test engines w ill be inappropriately excluded from the “MACT floor” engine population, this approach also facilitates consideration of the range of emissions for best performing engines and CO emi ssions variability. INGAA analysis and discussion in Sections 3 and 4 use this approac h for identifying the engines in the “MACT floor”.

2.2 MACT Floor Variability
As noted above, EPA has indicated that review of em issions variability should be limited to the “MACT floor” units – i.e., the engine popula tion in the best performing 12%. This report does not

discuss possible alternatives to this interpretati on for the variability assessment; however, the EPA approach does introduc e limitations when considering the vast array of engine types and applications.

For example, it is commonly understood that ambient conditions (e.g., temperature, humidity or precipitation) and elevation can impact emissions. Both higher elevation and cooler ambient temperature can increase CO emission s. If data from the MACT floor engine population are limited to engines at lower e levation or from warmer weather tests, than variability associated with these factors will not be captured. In addition, some engines with multiple tests over a broad range of o perating conditions may provide informative emissions variability data; however, if the lowest CO emissions are not within the best performing 12%, then that data set is not included in the analysis.

These factors, along with the fact that the CO data in this report are not based on a test program designed to characterize and understand var iability but rather are primarily from high load compliance tests, indicate that the emiss ions variability in the data set is likely to be conservative and under-estimate the CO emissi ons variability that will occur on best performing engines in practice. The INGAA data rep resent a relatively large data set, and it is understood that there are practical limit ations to the amount of data and emissions characterization studies that can be comp leted for an equipment category as diverse as reciprocating internal combustion engine s. Nonetheless, it is important to consider these limiting factors when assessing vari ability.

This report is an “emissions data report” with comp lementary technical discussion, and detailed citations and legal justification for cons idering variability are not provided. However, a review of recent Court decisions provide s insight into assessing variability when establishing the MACT floor for existing engin es. The 2007 Brick MACT encapsulates many of these decisions by referring t o the recent record from other NESHAP challenges. Examples include:Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

8 • The Brick MACT decision reiterates a finding from t he 2001 Cement Kiln MACT decision and a related 1999 decision where the D.C. Circuit Court explained, “EPA would be justified in setting the floors at a level that is a reasonable estimate of the performance of the ‘best controlled similar unit’ u nder the worst reasonably foreseeable circumstances.”

• “Cement Kiln” also acknowledges that it is accepta ble for EPA to consider the range of emissions from the best performing sources and t hat results at more adverse conditions “are more helpful than normal operating data would be in estimating performance under a variety of conditions and thus in helping to assure that properly designed and operated sources can achieve the stand ard.”

• The Brick MACT decision also references the 2003 Mo ssville Environmental Action versus EPA decision in which the D.C. Circuit Court “...held that floors may legitimately account for variability because “each [source] must meet the [specified] standard every day and under all operating conditio ns.”

• A similar theme is evident in a 1999 Sierra Club ve rsus EPA decision noting that the MACT floor standard must be achieved at all times a nd relevant factors should be considered, “under the most adverse circumstances w hich can reasonably be expected to recur.”

Thus, it is acceptable and expected for EPA to cons ider emission levels associated with normally anticipated and recurring operating condit ions, and Court decisions acknowledge that data from more adverse operating c onditions may better inform the basis of the standard. For the context of the lean burn engine emission standard considered in this report, higher CO emissions asso ciated with reasonable operating conditions likely to recur are of special interest. These operating conditions and associated emissions are of interest due to the nat ure of the dataset, where high load compliance tests are prevalent due to the basis for historical engine tests. Thus, the data distribution is not indicative of actual day-to-day operations and more adverse conditions (for CO emissions) such as low load are significant ly under-represented.

In addition, Court cases buttress EPA’s position th at the floor should not be based on “worst performer” units with the MACT floor technol ogy (i.e., lean burn engines without HAP/CO control for this standard) that are not with in the best performing 12%. For example, the Brick MACT decision references a Cemen t Kiln MACT finding, “...that EPA may not use emission levels of the worst perfor mers to estimate variability of the best performers without a demonstrated relationship between the two...”. Demonstrating a relationship could provide an avenue to consider variability from units outside the top 12% (e.g., a unit not within the floor that is the same make and model as a MACT floor unit but located at a different elevation). Howeve r, this is not pursued in the analysis in this report.

In summary, in considering variability, INGAA recom mends that EPA:

• Identify “best performing” engines based on the low est CO emissions for engines with multiple tests;Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

9 • Incorporate the range of emissions from best perfor ming engines into the standard setting process;

• Consider whether the operating conditions associate d with higher CO test results points are within the envelope of reasonable operat ions and likely to recur;

• Consider that the CO emission data distribution for this dataset is not indicative of actual day-to-day operations and more adverse condi tions for CO emissions such as low load are under-represented;

• Consider that the units must meet the standard ever y day and under all operating conditions; and

• Establish a standard that MACT floor units can meet if operating “under the most adverse circumstances which can reasonably be expec ted to recur.”

In Sections 3 and 4, data are summarized for the en gines that comprise the best performing 12%. The analysis and discussion of the CO emissions data collected by INGAA are based on the principles discussed above.

3.0 Data Summary and Discussion: Four-Stroke Cycle Lean Burn Engines

This section discusses the CO emissions data for 4- stroke lean burn engines, and focuses on emissions for the best performing 12% of engines . CO emissions data are available from eighty-five 4SLB engines with over 1,000 test runs. Engine size ranged from approximately 600 hp to 7,800 hp and includes large bore, slow speed “integral” engines and higher speed separable engines. Integral engin es are common in gas transmission and include the engine and compressor (i.e., driven equipment) in one package with both driven off a common crankshaft. For separable engi nes (e.g., Caterpillar and Waukesha engines), the driven equipment (e.g., compressor, p ump, electric generator) is a separate package linked to the engine drive shaft.

Because these data are from gas transmission, the m ost prevalent engine manufacturer in the data set is Ingersoll Rand, which is the primar y 4SLB integral engine manufacturer. Other engine manufacturers represented within the d ata set include Cooper Bessemer, Caterpillar, Waukesha, Superior, and Wartsila. Sin ce INGAA members participated in the EPA testing for the RICE MACT at the Colorado S tate University EECL, the CSU Waukesha 3521GL engine is included in this report. Emissions data are in Appendix A, but this 4SLB engine is not in the best performing 12%.

The emissions review and analysis, and data present ation are consistent with the discussion in Section 2. When a single test includ ed multiple test runs (e.g., 3-run compliance test), the average of the three runs was used for comparison with other engines. This is consistent with the EPA diesel en gines data presentation for the March 2010 RICE NESHAP amendments. When an engine has da ta for more than one test, the lowest (i.e., best performing) emissions level from the multiple tests was used for comparison with other engines. Based on this compa rison, the engine population that comprises the best performing 12% was identified. Eighty six engines were evaluatedTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

10 and eleven engines comprise the best performing 12% . This evaluation is termed the “MACT floor” and these engines are referred to as “ MACT floor units” or “MACT floor engines” in this report.

All of the 4SLB data are presented in Appendix A, w ith the individual tests associated with the eleven MACT floor engines presented in App endix A-1 and the remaining engines in Appendix A-2. Each test run is shown in a single row in the data tables, and the average of multiple runs at a common operating condition is shown where applicable. INGAA members provided summary data and test report s for MACT floor engines will be provided to EPA separately.

For both 4SLB engines and 2SLB engines in Section 4 , standard test methods were used. Tests were typically to demonstrate compliance with emission limits (e.g., annual tests, quarterly tests) or in some cases to collect data f or initial Title V permits or define an engine specific emission rate. Standard methods we re used including EPA reference methods (e.g., Method 10 for CO), the ASTM portable analyzer test method, or other standard portable methods (e.g., state sanctioned m ethods). Additional detail on test methods and data quality assurance for MACT floor e ngines is available in test reports that will be provided separately.

Table 1 presents summary information for the best p erforming 12% of the engines (i.e. the MACT Floor units), including the minimum emissi ons, maximum emissions, number of tests, and horsepower range for the tests. The engines are ranked based on the minimum emission level. In addition to the MACT fl oor units, the next two best performing engines are shown to indicate the next u nits that would be included in the MACT floor if the number of MACT floor units change s (e.g., other data are available that increases the number of MACT floor units). In addition, Table 1 indicates whether the engines are equipped with low emission combusti on (LEC) technology for lower NOx emissions. LEC is a technology difference that could warrant a separate subcategory, but since both engine types are repres ented in the floor, this does not appear
necessary.Technical Report: Natural Gas-Fired Engine Emissions Data for MACT FloorApril 201011Table 1. Summary of INGAA CO Emissions Data for 4SLB MACT Floor UnitsACO(ppm, 15% O2)PerformanceRankID No.MakeModelMinMax#TestsEMin. LoadTested (%)hp RangeTestedBLECC1 1 Ingersoll Rand 512 KVS 114 214 16 78 1,959 – 2,508 Yes2 2 Cooper Bessemer LSV-16 123 140 3 78 3,347 – 4,278 No3 3 Ingersoll Rand 36 KVS 124 270 16 76 798 – 1,044Yes4 4 Ingersoll Rand KVH-616 128 240 13 57 2,393 – 4,209 No5 5 Ingersoll Rand 512 KVS 131 226 16 80 1,626 – 2,040 Yes6 6 Cooper Bessemer LSV-16 135 144 3 82 3,550 – 4,323 No7 7 Ingersoll Rand 36 KVS-FT 137 375 11 47 472 – 990DYes8 8 Ingersoll Rand 36 KVS 139 298 16 71 705 – 987 Yes9 9 Caterpillar G3516 141 196 5 76 659 – 861 Yes10 10 Ingersoll Rand KVT 512 149 226 6 67 2,024 – 2,921 No11A11 Ingersoll Rand KVSR 412 153 223 2 88 1,793 – 2,044 Yes12 12 Waukesha 3521GL 154 338 3 75 582 – 782 Yes13 13 Superior 12SGTB 159 254 38 79F1,611 – 2,026FYesAThe first eleven engines comprise the MACT floor from the INGAA data. The next two best performing engines are also listed.BMaximum horsepower tested is at or near maximum rated load.CLow (NOx) Emission Combustion configuration (e.g.,enhanced ignition and/or mixing, pre-combustion chambers, turbocharging).DEngine ID No. 7 included “operating map” testing in March 2006. Multiple operating conditions were run to map the engine from47% to 99% load. This is the broadest load range tested for any of the 4SLB engines in the MACT floorand the highest COemissions are associated with the low load test condition.ENumber of “tests” at unique conditions; not numberof test runs. A multi-test run average (e.g., 3-run compliance test) is counted as 1 test.FLoad not available for all tests associated with quarterly portable analyzer tests.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

12 3.1 Comparison with EPA 4SLB Data

INGAA discussed the EPA database emission data for 4SLB engines in its June 2009 comments. Those data are not presented in this report, but IN GAA briefly reviewed the EPA data for comparison to the engines and CO emissions in Table 1. There are about 12 uncontrolled 4SLB engines in the EPA database with CO emission levels ranging from less than 100 ppmv to 420 ppmv. Two or three engines have “best performing” CO emissions commensurate with the MACT floor engines in Table 1. Nearly all of the t ests are at relatively high load (80% or higher) and there are no engines with multiple test s that include low load (i.e. < 60 - 70%) data in the EPA data set. The EPA CSU engine was tested at loads as low as 59% of full load with CO emissions as high as 420 ppmv, but its lowest emiss ion test was over 200 ppmv and thus it is not in the best performing 12% of the engine population

.
If the EPA database engines are combined with the I NGAA 4SLB data, the new total engine count would result in twelve or thirteen total engi nes in the MACT floor; these would include two or three engines from the EPA database (i.e., e ngine-specific identification is not clear in the EPA database and a “MACT floor” engine from the EPA database may be two similar engines or a single engine with multiple tests). These engine s were tested at one point in time at high load and do not provide insight into variability. Thus, integrating the EPA and INGAA engines into a single data set should not significantly impact the determination of the MACT floor units shown in Table 1. In addition, that data integration sho uld not significantly impact the variability analysis.

As discussed in Section 2, INGAA believes that the variability analysis needs to consider the range of emissions, and the related operating condi tions for the emissions. The data in Table 1 and Appendix A document that nearly all the emissio n tests were conducted at higher load, typically 80% load or higher, and there are very fe w low load tests. The lack of low load data is not indicative of the typical operating profile for lean burn engines in common applications, but rather due to the preponderance of compliance tests emissions data, where high load is typically required for demonstrating compliance with NOx limi ts. Variability review should thus value tests on lean burn MACT floor engines that are comp leted over a range of operating conditions, such as load, because these tests provide more insi ght into emissions variability and operation under adverse conditions. This is consistent with the Court’s conclusion, noted in Section 2, that data under more adverse conditions are more helpful in establishing the standard.

Based on the March 2010 RICE NESHAP, the emission s tandard will apply under all operating conditions other than startup. Thus, the operating conditions associated with CO emissions data for the MACT floor engines must be considered when assessing variability. This approach is warranted to achieve the directive of recent Court decisions that units must comply every day and under all operating conditions, and that it is reasonable to establish a standard that MACT floor units can meet if operating “under the most a dverse circumstances which can reasonably be expected to recur.” Lower load is a common and rec urring condition for engines.

3.2 Variability and Factors that Influence 4SLB CO Emis sions
For many gas transmission applications, it is commo nly understood that a reciprocating engine is the preferred compressor driver (i.e., rather than a combustion turbine) because a reciprocatingTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

13 engine performs better at reduced load and increase s operational flexibility. While higher load operation is generally preferable and inherent to p ipeline system operating principles, gas transmission operations respond to pipeline demands , which require operational flexibility and lower load operation. Thus, reciprocating engines will continue to be an integral component of natural gas pipeline operational flexibility, and l ower load operation is and will continue to be an inherent part of reciprocating engine operations in natural gas transmission. However, as discussed in Section 2, available emissions data ar e predominantly from high load compliance tests. The 4SLB data in the EPA database are also primarily high load data. With lower load significantly under-represented in the available da ta, special consideration of low load data is warranted when assessing emissions variability.

Thus, even though the INGAA data set includes many engines and test points, the population of test data is predominately from high load complianc e tests, and the data do not adequately or uniformly encompass or capture emissions under more adverse conditions, such as operation at lower load operation or leaner air-to-fuel ratio wh ere CO emissions will be higher. Since the MACT floor emission limit must be achievable at all times, proper consideration of emissions variability and the range of potential engine opera ting conditions is imperative to the analysis. ”At all times” achievability should not be overlook ed or dismissed when establishing the MACT floor, because failure to assess lower load operati on and reasonable operating envelopes could result in technically questionable conclusions. Th is issue is discussed further below. Section 4.2 on 2SLB engines provides a hypothetical example of how data from more adverse operating conditions better inform the variability assessment . The example in Section 4.2 illustrates why it is reasonable to consider the relevance of data tha t better capture emissions over a range of operating conditions when assessing variability and that same rationale applies for 4SLB engines in this data set.

From Table 1, only one of the 4SLB MACT floor engin es has data over an operating envelope that includes less than 50% load – the Ingersoll Ra nd 36 KVS-FT engine, the seventh engine listed in Table 1 with Unit Identification Number 7 . The tested load range is well within normal operating scenarios and lower load operation (i.e., lower than 47% load) will recur in practice for gas transmission engines. This engine is rated at 1,000 hp and was purposefully tested over a range of common operating conditions in March 2006. This existing dataset is especially valuable because it provides better insight into ad verse operating conditions and emissions variability across common operating conditions than other 4SLB engines in the INGAA data set. The test data for this engine are presented in Appe ndix A-1 and summarized in Table 2. The engine was tested over a range of common loads and speeds; but even for this more robust data set the minimum load was 47%, and lower operating l oads occur in normal operation.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

14

Table 2. CO Emissions Summary for Ingersoll Rand 3 6 KVS-FT.

Test No. Load (hp) Speed (rpm) % load %O 2 CO (ppm, at 15% O 2 )

1 573 270 57 12.4 230

2 472 270 47 13.4 375

3 990 330 99 11.8 137

4 926 300 93 12.2 202

5 853 270 85 12.1 182

6 725 270 73 11.9 207

7 795 300 80 11.0 200

8 872 330 87 11.0 175

9 752 330 75 11.2 213

10 675 300 68 10.9 178

11 571 270 57 11.2 182

The Ingersoll Rand 36 KVS-FT engine data demonstrat e expected CO emission trends, with CO lowest at high load and increasing with lower loads . Although these data represent a more complete range of operating conditions and loads th an other 4SLB MACT floor engines, the data do not capture the full range of expected operating condi tions. For example, engine operation at lower than 47% of rated load will occur for gas tra nsmission engines during normal operations. These March tests occurred at relatively cool ambie nt temperatures of 29 to 37 o F, but this range does not represent minimum temperatures for this si te, and lower temperature can increase CO emissions.

Thus, while the test at 47% load represents the mos t adverse condition for this particular test program, it is not indicative of the most adverse c ondition likely to recur – i.e., lower load and/or cooler temperature are two parameters that will adv ersely effect CO emissions and would likely result in higher CO emissions over the course of an nual operation. Those effects are not captured in this data set or other data that are av ailable for this review, but support the assertion that 375 ppmv CO (at 15% O 2 ) for the low load (47%) test does not fully addres s the variability that is inherent to this MACT floor engine.

The data set for this MACT floor analysis is imperf ect, and it is clear that the range of emissions (i.e., variability) for the MACT floor engines is l imited by the fact that most tests were conducted at high load for compliance purposes, whi le the standard will require compliance under all operating conditions. Similarly, even th e most robust test data within the MACT floor engines are limited by the testing completed. The 2006 test was not designed or conducted to evaluate emissions over the full range of operating conditions, but fortuitously included tests at lower load than other MACT floor units, as well as high load tests. Thus, when considering operating conditions and emissions variability that are likely to recur for MACT floor engines, it is reasonable to conclude that a 4SLB CO standard o f at least 375 ppmv is warranted.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

15 While INGAA understands that the regulatory criteri a and standards differ, this emission level can be compared with other emission results and tec hnology driven standards to provide context. For example, the spark ignition RICE New Source Per formance Standard (NSPS) is based on “best demonstrated technology” for new engines and the NSPS does not require catalytic co ntrol – i.e., the technology basis is similar to the RICE NESHAP MACT floor. The NSPS CO standard is 540 ppmv (at 15% O 2 ) for new, modified and reconstructed engines, and decreases to 270 ppmv for new, non-emergency units manufactured after 2010 or 2011 (date depends on NSPS subcategory). Thus, the most adverse emission level shown in Table 2 is within the range of anticipated CO emissions for a new engine with b est demonstrated technology. For another comparison, the EPA-sponsored 4SLB RICE MACT tests at CSU include testing over a reasonable operating envelope, but the minimum load was only about 59% of rated capacity. CO emissions for those tests ranged from 305 to 420 pp mv, with the highest emissions actually from a higher load test with marginally leaner operation (i.e., slightly higher excess O 2 ).

4.0 Data Summary and Discussion: Two-Stroke Cycle Lean Burn Engines

This section discusses the CO emissions data for 2- stroke lean burn engines, and focuses on emissions for the best performing 12% of engines. The majority of compressor drivers in the U.S. natural gas transmission sector are 2SLB integ ral engines. Because of this prevalence, there are many tests available; however, as discussed in Section 3 for 4SLB engines, the vast majority are high load compliance tests in response to NOx r equirements. Data are available from 325 engines with over 3,000 test runs. Despite this we alth of data, there are still limitations due to the lack of low load tests. In addition, the 2SLB engine category could be more complicated due to technical differences inherent to engine design that could warrant the need for additional subcategories. Example technical differences inclu de cylinder displacement (i.e., size), air supply (e.g., turbo-charged, piston scavenged), and air flow (e.g., “uniflow” versus loop scavenged designs).

These and other factors present technical differenc es that affect the engine “type” and characteristic emissions – and thus may warrant con sideration for additional 2SLB subcategories. However, INGAA believes that with proper considerat ion of variability, the emission differences for different 2SLB engine types are minimized. Thu s, despite these design differences, it may be feasible to avoid additional subcategorization if a MACT floor engine has test data over a broad enough range of operating conditions to encompass e missions variability indicative of performance for the MACT floor engines for differen t possible subcategories – i.e., variability exhibited across the operating envelope may reasona bly capture the emission differences due to design and operational differences between 2SLB eng ine types. Or, expressed another way, while the lowest or best performing emissions for d ifferent possible subcategories may be significant and reflective of different engine type s, emissions variability across the operating range for different engine types may suppress some of the differences seen at the “best performing” point (i.e., lowest emissions exhibited at high load and nominal speed and AFR). These issues are discussed further below, after the summary data for “MACT floor” engines are presented.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

16 Two-stroke lean burn engines are typically large bo re, slow speed integral units and the size of tested engines ranged from under 300 hp (Ajax engin es) to more than 10,000 hp with most engines from 1,000 to 4,000 hp. The most prevalent 2SLB engine types (based on manufacturer) are Cooper Bessemer, Clark, Worthington, and Cooper Cameron (Ajax). Within the engine lines produced by these manufacturers, operated by INGAA members, and represented in the INGAA dataset, there are more 2SLB engine models in this report with unique design and technical attributes than 4SLB engine models with design and technical attributes that significantly impact CO emissions. These array of differences are due i n part to different ways of “handling the air” to promote cylinder scavenging (i.e., sweep out the exhaust products for the two-stroke cycle).

In addition to the INGAA data, 2SLB Ajax engine tes t data is presented in this report from the Exterran, JW Power and CSI (EJC) Group that also re cently submitted a test report to EPA for rich burn engines. The Ajax engine CO emissions te sts completed during the EJC test program were limited in scope. The CO data were reviewed a long with the INGAA data and CSU engine data (discussed below). None of the Ajax engines, including an Ajax engine operated by an INGAA member, exhibited CO emissions low enough for inclusion in the MACT floor. Thus, the data for these engines are shown in Appendix B- 3 with units that comprise 88% of the 2SLB engine population that are not MACT floor engines.

In addition, INGAA members participated in EPA test ing for the RICE MACT at CSU, and the CSU Cooper Bessemer GMV-4TF engine is included in t his report, with a separate section discussing the engine and emission results. This e ngine is extremely important to the 2SLB engine dataset because:

• The Cooper GMV engine is the most prevalent engine model in natural gas transmission. There are several different primary designs mainly differentiated by air handling (e.g., piston scavenged, blower scavenged, turbo-charged);

• The CSU engine cylinder bore and stroke, parameters that impact emission performance, are characteristic of in-service engines. While the CS U engine has a lower full load rating than most field applications of Cooper GMV engines, this difference is due to the number of cylinders – i.e., four cylinders for the CSU engine where eight is the most standard GMV configuration. Despite this difference in maximum rating, the key “size” characteristics (cylinder bore and stroke) and engine systems that impact performance and emissions for the CSU GMV-4 are the same as GMV engines with more cyl inders and higher rated capacities.

• The EPA-sponsored tests at CSU captured some operat ional variability. As discussed below, the “best performing” CO results from the CSU test matrix for the EPA-sponsored RICE MACT testing are just marginally higher than the th reshold that defines the best performing 12%. Thus, the engine would not be a MACT floor un it based solely on the EPA tests. However, this engine has been used for numerous oth er studies and supplemental data are available from “standard” engine configurations (i. e., not “experimental” configurations associated with technology review or development pr ojects at the CSU test bed) with a wider range of emissions. Additional supplemental data a re further discussed below and presented in Appendix B-2. CO emissions from these supplemen tal tests include test points with marginally lower (and marginally higher) emissions than from the EPA tests. This results in the CSU engine being in the best performing 12%, an d thus establishes the engine as a MACT floor unit.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

17 • For 2SLB engines, the full range of emissions data from the CSU engine provides the best data set to assess variability for 2SLB engines. Al though, like other engines, low load test data are limited. The lack of low load emissions d ata is due to the historical focus on NOx emissions; because NOx emissions decrease at lower load for 2SLB engines, minimal low load data have been collected. However, some emiss ion data are available for engine operation at lower loads and marginally higher air- to-fuel ratios, and these data provide an indication of CO variability at operating condition s that recur in practice for 2SLB engines.

The emissions review and analysis, and data present ation in this section are consistent with the discussion in Section 2. When a single test includ ed multiple tests runs (e.g., 3-run compliance test), the average of the three runs was used for e ngine-to-engine comparisons. This is consistent with the EPA diesel engines data presentation for t he March 2010 RICE NESHAP amendments. When an engine has data for more than one test, the lowest (i.e., best performing) emissions level from the multiple tests was used for comparison wit h other engines. Based on this comparison, the engine population that comprises the best perfo rming 12% was identified. 325 engines were evaluated, so thirty-nine engines comprise the best performing 12% if all 2SLB units are grouped in a single subcategory. (A section below discusse s the possible need for additional subcategories but INGAA believes that additional su bcategories may not be necessary if emissions variability is assessed as discussed in S ections 4.2 and 4.3.)

All of the 2SLB emission test data are presented in Appendix B, with the MACT floor engines in Appendix B-1, CSU engine data tabulated in Appendix B-2, and the balance of the 2SLB engine population in Appendix B-3. Each test run is shown in a single row in the data tables, and the average of multiple runs at a common operating cond ition is shown where appropriate.

Table 3 presents summary information for the best p erforming 12% of the 2SLB engines (i.e. the MACT floor units) from the INGAA data set, includin g the minimum CO emissions, maximum CO emissions, number of tests, and horsepower range for the tests. The CSU engine is included in the MACT floor. The engines are ranked based on the minimum emission level. In addition to the MACT floor units, the next three best perfor ming engines are shown to indicate the next units that would be included in the MACT floor if t he number of MACT floor units changes (e.g., other data are available that increases the number of MACT floor units). In addition, Table 3 indicates whether the engines are LEC-equipped fo r lower NOx emissions. LEC includes technology differences that could warrant separate subcategories.Technical Report: Natural Gas-Fired Engine Emissions Data for MACT FloorApril 201018Table 3. Summary of INGAA CO Emissions Data for 2SLB MACT Floor Units (39 units comprise the top 12%).ACO(ppm, 15% O2)PerformanceRankID No.MakeModelMinMax#TestsEApproximateMin. LoadTested (%)hp RangeTestedBLECC1 2S-90 Cooper Bessemer GMVA-1033 104 11 84% 1,110 – 1,318 No2 2S-137Cooper Bessemer GMW-6TF 40 198 13 53% 596 – 1,117No3 2S-57 Cooper Bessemer GMV-10TF 43 43 1 >90% 982 –1,235 No4 2S-80 Cooper Bessemer GMVA-10 50 56 2 95% 1,235 –1,300 No5 2S-86 Cooper Bessemer GMVA-10 51 108 10 80% 982 –1,235 No6 2S-79 Cooper Bessemer GMVA-10 52 52 1 >90% 1,300No7 2S-145Cooper Bessemer GMV-8TF 53 142 13 75% 1,397 – 1,856No8 2S-96 Cooper Bessemer GMVC-10 53 53 1 >90% 1,790No9 2S-132Cooper Bessemer GMW-10 53 325 5 72% 1,863 – 2,582 Yes10 2S-55 Cooper Bessemer GMV-10TF 54 54 1 >90% 875No11 2S-78 Cooper Bessemer GMVA-1056 56 1 >90% 1,270 No12 2S-141Cooper Bessemer GMW-6TF 56 127 10 67% 927 – 1,379 No13 2S-78 Cooper Bessemer GMVA-10 56 56 1 >90% 1,270No14 2S-91 Cooper Bessemer GMVA-10 57 114 12 78% 977– 1,260 No15 CSUA,DCooper Bessemer GMV-4TF 58 407 98 62% 273 – 441 Y/ N16 2S-85 Cooper Bessemer GMVA-10 58 91 10 86% 1,131– 1,320 No17 2S-87 Cooper Bessemer GMVA-10 58 190 10 86% 1,137 – 1,325 No18 2S-97 Cooper Bessemer GMVC-10 59 59 1 >90% 1,780No19 2S-144Cooper Bessemer GMW-8TF 59 301 14 64% 1,240 – 1,948No20 2S-140Cooper Bessemer GMW-6TF 59 238 14 77% 967 – 1,254 No21 2S-124Cooper Bessemer GMVH-8 59 59 1 >90% 1,790 No22 2S-88 Cooper Bessemer GMVA-10 61 161 10 89% 1,110 – 1,250 No23 2S-105Cooper Bessemer GMVH-12 61 64 2 90% 2,457 – 2,737 Yes24 2S-89 Cooper Bessemer GMVA-10 62 98 10 75% 959 –1,275 No25 2S-82 Cooper Bessemer GMVA-10 62 146 9 >90% 1,110 No26 2S-108Cooper Bessemer GMVH-12 63 125 15 91% 2,489 – 2,725YesTechnical Report: Natural Gas-Fired Engine Emissions Data for MACT FloorApril 201019CO(ppm, 15% O2)PerformanceRankID No.MakeModelMinMax#TestsEApproximateMin. LoadTested (%)hp RangeTestedBLECC27 2S-115Cooper Bessemer GMVH-12 64 118 27 86% 2,418 – 2,824Yes28 2S-118Cooper Bessemer GMVH-12 64 117 27 87% 2,375 – 2,726Yes29 2S-134Cooper Bessemer GMW-6TF 65 135 13 55% 625 – 1,136 No30 2S-119Cooper Bessemer GMVH-12 65 123 17 65% 1,775 – 2,739Yes31 2S-113Cooper Bessemer GMVH-12 67 122 27 73% 1,969 – 2,708Yes32 2S-95 Cooper Bessemer GMVB-10 67 97 24 73% 1,026– 1,400 Yes33 2S-146Cooper Bessemer GMW-8TF 68 150 13 82% 1,467 – 1,800No34 2S-110Cooper Bessemer GMVH-12 68 128 27 80% 2,175 – 2,708Yes35 2S-83 Cooper Bessemer GMVA-10 68 95 10 62% 811 –1,303 No36 2S-117Cooper Bessemer GMVH-12 69 122 27 84% 2,330 – 2,765Yes37 2S-112Cooper Bessemer GMVH-12 69 132 27 91% 2,541 – 2,787Yes38 2S-139Cooper Bessemer GMW-6TF 69 278 13 60% 749 – 1,253No39A2S-84 Cooper Bessemer GMVA-10 70 123 9 82% 1,010 –1,235 No40 2S-129Cooper Bessemer GMW-10 71 327 10 85% 2,021 – 2,374No41 2S-107Cooper Bessemer GMVH-12 71 117 16 89% 2,402 – 2,697YesAThe first 39 engines comprise the MACT floor fromthe INGAA data (plus CSU engine) and EJC Group data. The next two enginesin the list are also shown.BMaximum horsepower tested is at or near maximum rated load.CLow (NOx) Emission Combustion configuration (e.g.,enhanced ignition and/or mixing, pre-combustion chambers, turbocharging)DThe CSU engine is included in the MACT floor. Data are presented in Appendix B-2, and the data are discussed in Section 4.2.ENumber of “tests” at unique conditions; not numberof test runs. Counts multi-test run average (e.g.,3-run compliance test) as one test.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

20 4.1 Overview of MACT Floor Engines and 2SLB Engine Subcategories

INGAA discussed the EPA database emission data for 2SLB engines in its June 2009 comments. Those data are not presented in this report, with t he exception of the CSU engine, as discussed below. There are about fifteen to twenty 2SLB engi nes in the EPA database, and several have emissions at or below the MACT threshold of 70 ppmv from Table 3. The integration of EPA engines with the data in this report would not have a significant impact on the analysis. However, in comparing CSU data, an apparent discrep ancy was discovered. It appears that the EPA database recorded “as measured” CO values as “c orrected to 15% O 2 .” The original CSUEPA report was reviewed to confirm that the CSU CO emissions data presented in this document are correct and based on the original data in the r eport. (The report citation is provided in Section 4.3.)

The CSU engine is a Cooper Bessemer GMV-4TF engine and the MACT floor engines in Table 3 are all Cooper GMV and GMW engines. Other Cooper engine models, or Clark or Worthington engines are not represented in the MACT floor. This is likely due to two primary factors: Cooper engines are relatively “well-mixed” in comparison to Clarks and Worthingtons (e.g., Worthingtons use “uniflow” rather than “loop ed” air scavenging which significantly affects mixing), and the GMV and GMW series include many en gines that are not turbo-charged. In addition, the GMV cylinders are smaller (smaller bo re and stroke or swept cylinder volume) than nearly all other 2SLB engines in the INGAA dataset, with Ajax engines an exception. More recent vintage Cooper engines include turbochargers . Thus, a 2SLB floor comprised entirely of Cooper GMV and GMW engines could inappropriately re present other types of 2SLB engines, and additional subcategories may need to be conside red to address different types of engines. However, if variability is appropriately considered , the need for additional subcategories may be mitigated.

INGAA understands that emission levels are not the basis for defining a subcategory. This decision must be based on unique size, type or clas s attributes according to the Clean Air Act. While detailed documentation is not provided in thi s report, there are distinct differences between different types of 2SLB engines, and those differences are reflected in the CO emissions data. Thus, for comparison to the summary emission s data provided in Table 3, Table 4 presents the best performing units for 2SLB engine types not represented in the MACT floor (i.e. engines other than Cooper GMVs and GMWs). In addition, det ailed data in Appendix B show different characteristic emissions for different 2SLB engine types. There are inherent physical and operational characteristics within the 2SLB subcate gory, and INGAA believes that additional subcategories based on different types of technolog y (or different size) could be justified and may be warranted. However, this would add complexi ty to rule development and implementation. Review of the emission ranges in T able 3 and Table 4 indicates that considering variability within the data set for GMV s – primarily based on more comprehensive data from CSU tests – offsets some of the CO emissi on differences evident at the lowest or best performing points. Thus, properly accounting for v ariability may in part reconcile emission differences that could otherwise compel INGAA to st rongly support developing additional 2SLB subcategories.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

21 Table 4. Summary of Best Performing 2SLB Engines Excluding C ooper GMV and GMW Engines.

A Clark, Worthington and Cooper Engines (excluding G MV and GMW) total 175 engines, thus 21 units comprise the best performing 12% for this engine group.

The lowest emissions (i.e., minimum CO) and cut poi nt for the best performing 12 percent is higher for these engines than units in Table 3. In addition, some engines exhibit a significantly higher maximum. However, the upper end of the CO e missions range from the CSU data set (in Table 3) is similar in magnitude to some engines in Table 4. Appendix B data for all engines, including the 88% not in the MACT floor, indicate t hat many of the makes / models of engines in Table 4 have emissions significantly higher than the best performing units shown in Table 4.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

22 Thus, the range of emissions (variability) in Table s 3 and 4 is not high enough to ensure that many of the engines in the INGAA data set can achie ve those levels without additional action; that is, variability is not being assessed in this report as a convenient means to facilitate compliance, but rather as an imperative part of the standard setting process.

The range of emissions for the CSU engine provides a reasonable means to assess variability. If all 2SLB engines are grouped into one subcategory r egardless of technical differences, then over thirty engines comprise the MACT floor and, as show n in Table 3, the CSU engine is included in the best performing 12 percent. However, if the en gines in Table 3 are used to establish a standard without consideration of lower load and ot her common and more adverse operating conditions, then INGAA would recommend reviewing th e need for additional subcategories. INGAA does not provide a detailed technical basis f or subcategories in this report. However, if needed, that technical information can be provided so that the different 2SLB engine types can be better documented and subcategories can be suppo rted.

4.2 Emissions Variability Assessment
As discussed in Section 3, reciprocating engines ar e preferentially used in gas transmission because of their operational flexibility and abilit y to perform reasonably well across a range of loads based on pipeline demand. INGAA believes tha t it is appropriate, technically justifiable, and consistent with D.C. Circuit Court directives t o carefully consider the available emissions data that best captures the range of expected opera tions (i.e., adverse conditions that are reasonably likely to recur) when assessing variabil ity. If an emissions dataset for variability analysis is homogeneous (i.e., all or most units te sted under similar operating conditions that encompass the expected/normal range of engine opera tion), determining and considering which of the available emissions data best captures the r ange of expected operations is less of an issue. However, even though the INGAA data set inc ludes many engines and test points, the population of test data is predominately from high load compliance tests and does not adequately encompass or capture emissions under more adverse c onditions, such as lower load operation, where CO emissions will be higher. Since the MACT floor emission limit must be achievable at all times, proper consideration of emissions variab ility and the range of potential engine operating conditions is imperative to the analysis. ”At all times” achievability should not be overlooked or dismissed when establishing the MACT floor, because failure to assess lower load operation and reasonable operating envelopes could result in technically questionable conclusions.

To illustrate this point, consider an example case where the initial step of MACT review has been completed and there are two “units” in the MAC T floor. Both units utilize the same technology. As is commonly observed for engines, t his example assumes that it is understood and technically supported that emissions for these units will vary across the operating envelope. One of the two units (unit 1) has a single data poi nt measured at optimal operating conditions (e.g., full load, warm ambient conditions, and nomi nal air to fuel ratio for a lean burn engine). Conversely, unit 2 has emissions data from multiple test conditions. One test condition for unit 2 is identical to the unit 1 data point (high load, a nd nominal settings) and results in similar emissions. The other data points for unit 2 cover the full operating envelope and include a range of operating conditions at different points in time ; that is, the emission data encompass seasonal variation (cold versus warm weather) and include a range of process operations. Although dataTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

23 from unit 2 show similar emissions under the simila r optimal operating condition, significant variability is exhibited in its more robust data se t. In this instance, it is appropriate and technically superior to assess variability based on the data set from the second unit.

In addition, if the unit 2 data are combined or int egrated with the single test from the first unit, different weighting should be applied to the datase ts. If each unit is assigned similar weighting, the technical insight on variability from the more complete data set will be compromised , and proper consideration will not have been given to th e range of observed operating conditions that are likely to recur as reflected in the unit 2 data

.
INGAA believes that it is imperative that technical objectives for assessing variability consider the range of reasonable operating conditions. In t his example, that would mean that the variability assessment would consider the range of emissions associated with the more robust data set from the second unit, and limitations asso ciated with the single data point from the first unit would be recognized.

Thus, the breadth of operating conditions and assoc iated CO emissions data from individual MACT floor engines should be considered when assess ing variability. This approach is warranted to achieve the directive of recent Court decisions that units must comply every day and under all operating conditions, that data under adverse conditions may be more informative, and that it is reasonable to establish a standard t hat MACT floor units can meet if operating “under the most adverse circumstances which can rea sonably be expected to recur.” Lower load is a common and recurring condition for engines tha t will impact CO emissions for lean burn engines.

4.3 Discussion of CSU 2SLB Engine Data and NOx – CO Tradeoff
The CSU Engines & Energy Conversion Laboratory Cooper-Bessemer GMV-4TF has four cylinders with 14 inch diameter cylinder bore and 1 4-inch piston stroke. The nominal speed is 300 rpm and the nominal maximum load is 440 brake-h orsepower. This engine is used to characterize emissions and evaluate the impacts of ignition and mixing enhancements on engine performance. It has been instrumental in supportin g the development of technologies that are reducing emissions in the existing gas transmission fleet. During the course of these evaluations, the CSU engine is often operated and t ested at standard, baseline configurations to provide a benchmark for the particular project. Th e standard configurations, typical of the 2SLB engine population, include an open combustion chamb er (OCC) design and a pre-combustion chamber (PCC) design. Emission data from multiple test projects that include standard configuration tests provide a dataset to evaluate e mission variability for a single engine. In addition to OCC and PCC, some open chamber tests us ed multi-strike spark plugs. The CSU data incorporate the impacts of time (e.g., differe nt ambient conditions, time lapse since engine maintenance) and normal range operating parameters (e.g. load, air-to-fuel ratio, ignition timing). Thus, these emissions data represent operation at c onditions that are reasonably expected to recur, and are common to the fleet of Cooper GMV an d other gas transmission engines.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

24 Table 5 presents emission measurement data, sorted from lowest to highest CO emissions, from test projects conducted on the CSU engine. These p rojects include the EPA sponsored testing 1 and an emissions tradeoff paper from a 1999 confere nce 2 . Additional data are provided from industry or manufacturer sponsored testing and thos e results are documented in Appendix B-2.

These data are for engine operation in standard, ba seline configurations and do not include emission data from engine operation associated with evaluating developmental or experimental control technologies. CO emissions range from 58 t o 407 ppmvd at 15% O 2 . These data also demonstrate the tradeoff between CO and NOx emissio ns, with NOx ranging from 8 to 1,317 ppmvd at 15% O 2 . These emissions are not indicative of long-term performance that is continuously achieved, but rather the range of emis sions that can occur under operating conditions associated with variations in load and e xcess air.

Figure 1 plots the CO emission data as a function o f NOx emissions. As expected, operations associated with higher NOx result in the lowest CO emissions. Thus, a too strident CO standard could compel operators to operate at conditions tha t result in higher NOx. The curve shows the familiar CO/NOx trade-off, illustrates the emission s variability, and demonstrates the overlap of the CO emissions data from different test projects at similar NOx emission levels. The data congruency supports the ability to consider emissio ns from these different points in time, and supplement the EPA program data already in the EPA database with additional test results. Additional data details are provided in Appendix B.

1 CSU-EPA 2000 – “Final Report: Testing a 2-Stroke Lean Burn Gas-Fired Reciprocating Internal Combusti on Engine to Determine the Effectiveness of an Oxidati on Catalyst System for Reduction of Hazardous Air Pollutants,” EPA/OAQPS, EPA-454/R-00-036a, July 200 0.

2 CSU GMC 1999 – “Carbon Pollutant Emissions and Eng ine Performance Trade-Offs vs NOx Emissions for Reciprocating Internal Combustion Engines Utilized in Gas Transmission Service.” Gary Hutcherson, CSU; Chad Fletcher, Enginuity International, Inc.; Greg Besho uri, Advanced Engine Technologies Corporation (AETC ). Presented at 1999 Gas Machinery Conference, Houston , October 6, 1999.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

25 Table 5. CSU CB GMV-4TF Standard Configurations E missions Data.

Load O2 CO NOx Project Test # % % dry ppmvd @ 15% O2
CSU-GMC 1999 4A-1 112% 13.5% 58 740 CSU-GMC 1999 2A-6 100% 13.4% 59 1,018 CSU-GMC 1999 0.10 86% 11.9% 59 1,116 CSU-GMC 1999 2B-3 101% 13.2% 61 1,315 CSU-GMC 1999 3A-6 86% 12.2% 61 1,159
CSU-GMC 1999 0.20 101% 13.6% 61 862
CSU-GMC 1999 4A-2 112% 13.6% 65 456
CSU-GMC 1999 2A-7 86% 13.4% 65 786 CSU-GMC 1999 4B-8 86% 12.0% 65 1,317
CSU-GMC 1999 2A-5 100% 13.6% 66 648
CSU-GMC 1999 0.40 112% 13.3% 66 797 CSU-GMC 1999 3B-1 112% 13.0% 67 1,154
CSU-GMC 1999 2A-4 101% 13.7% 68 560
CSU-GMC 1999 2A-8 100% 13.8% 69 585
CSU-GMC 1999 4A-3 112% 13.9% 71 275
CSU-GMC 1999 2B-2 100% 13.6% 72 750
CSU-GMC 1999 0.02 100% 13.9% 73 482
CSU-EPA PAH-1 85% 14.6% 73 304
CSU-EPA 6 100% 14.3% 75 202
CSU-EPA 4 86% 14.7% 75 306
CSU-GMC 1999 3B-2 112% 13.4% 75 826
CSU-GMC 1999 0.04 112% 13.4% 76 471
CSU-EPA 9A 100% 14.5% 78 123
CSU-GMC 1999 2A-3 100% 13.8% 78 331
CSU-EPA 10 100% 14.6% 78 145
CSU-EPA 13 100% 14.6% 81 88
CSU-GMC 1999 3A-1 86% 14.3% 81 248
CSU-GMC 1999 0.00 100% 14.0% 83 236
CSU-EPA 1 100% 14.6% 83 101
CSU-GMC 1999 0.00 112% 13.6% 84 283
CSU-GMC 1999 4A-4 112% 14.4% 85 117
CSU-GMC 1999 2A-2 101% 14.0% 85 184
CSU-GMC 1999 0.01 86% 14.5% 86 177
CSU-GMC 1999 3A-2 86% 14.4% 87 151
CSU-EPA 16 100% 14.6% 88 152
CSU-GMC 1999 3B-3 112% 13.7% 88 402
CSU-GMC 1999 2A-12 100% 13.8% 89 129
CSU-GMC 1999 1B-1 100% 14.0% 89 438
CSU-GMC 1999 2B-1 100% 14.0% 89 388
CSU-GMC 1999 4B-7 86% 14.4% 89 243
CSU-GMC 1999 0.00 100% 14.1% 91 141
CSU-EPA 15 100% 14.7% 92 133
CSU-GMC 1999 0.00 101% 13.8% 92 49
CSU-GMC 1999 4A-5 112% 14.5% 93 110
CSU-EPA 14 100% 14.6% 95 82Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

26 Table 5. CSU CB GMV-4TF Standard Configurations Em issions Data. (continued)

Load O2 CO NOx Project Test # % % dry ppmvd @ 15% O2
CSU-GMC 1999 0.00 86% 14.6% 95 87
CSU-GMC 1999 2A-1 101% 13.8% 96 134
CSU-GMC 1999 2A-9 101% 14.3% 98 133
CSU-GMC 1999 3A-3 86% 14.6% 99 120
CSU-GMC 1999 0.00 112% 14.2% 102 73
CSU-GMC 1999 2A-10 100% 14.2% 102 124
CSU-GMC 1999 0.00 100% 14.1% 102 88
CSU-GMC 1999 1B-2 101% 14.2% 105 223
CSU-GMC 1999 3A-4 86% 14.7% 109 99
CSU-GMC 1999 0.00 100% 14.2% 111 56
CSU-GMC 1999 4B-6 86% 14.7% 114 105
CSU-GMC 1999 1B-6 101% 14.3% 115 81
CSU-EPA 5 100% 15.1% 116 41
CSU-GMC 1999 0.00 112% 14.5% 116 51
CSU-GMC 1999 0.00 86% 14.7% 116 61
CSU-GMC 1999 2A-11 100% 13.8% 116 117
CSU-EPA 12 86% 15.3% 120 32
CSU-EPA PAH-3 85% 15.3% 121 30
CSU-GMC 1999 3A-5 86% 14.8% 122 94
CSU-EPA 11 86% 15.2% 123 29
CSU-GMC 1999 3B-4 112% 14.7% 124 68
CSU-EPA PAH-2 85% 15.4% 127 29
CSU-GMC 1999 0.00 112% 14.6% 130 51
CSU-GMC 1999 0.00 86% 14.7% 131 50
CSU-EPA 8 86% 15.6% 134 33
CSU-GMC 1999 0.00 100% 14.6% 136 46 PRCI PCC Eval FE_BL_BM2 100% 14.3% 141 88
CSU-GMC 1999 1B-5 100% 14.7% 142 32
CSU-GMC 1999 0.00 101% 14.8% 151 41
CSU-GMC 1999 4B-5 86% 15.0% 152 46
CSU-GMC 1999 0.00 86% 14.8% 152 46
CSU-GMC 1999 3B-5 112% 15.0% 158 29
CSU-GMC 1999 0.00 86% 15.0% 174 43
CSU-GMC 1999 1B-3 101% 15.0% 187 21
CSU-GMC 1999 4B-4 86% 15.1% 188 26 PRCI PCC Eval FE_BL_FS1 100% 14.5% 192 40 PRCI PCC Eval FE_BL_FS5 101% 14.5% 195 49 PRCI PCC Eval FE_BL_FS2 100% 14.6% 200 39 PRCI PCC Eval FE_BL_FS4 100% 14.5% 201 43 PRCI PCC Eval FE_BL_FS3 100% 14.5% 202 40
CSU-GMC 1999 3B-6 112% 15.1% 202 22 PRCI PCC Eval FE_BL_BM1 100% 14.6% 208 39
CSU-GMC 1999 4B-1 101% 15.2% 216 26
CSU-EPA 3 62% 16.1% 246 9
CSU-GMC 1999 4B-3 86% 15.2% 249 18Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

27 Table 5. CSU CB GMV-4TF Standard Configurations Em issions Data. (continued)

Load O2 CO NOx Project Test # % % dry ppmvd @ 15% O2
CSU-EPA 2-7 69% 15.8% 259 8 PRCI PCC Eval FE_BL_BM6 100% 14.8% 263 19 PRCI PCC Eval FE_BL_BM3 100% 14.8% 277 21 PRCI PCC Eval FE_BL_BM4 100% 14.8% 280 21 PRCI PCC Eval FE_BL_BM5 100% 14.8% 282 21
CSU-GMC 1999 1B-4 101% 15.5% 343 10 PRCI PCC Eval FE_BL_BM7 100% 14.9% 369 15
CSU-GMC 1999 4B-2 86% 15.8% 407 11

CSU Cooper GMV-4TF CO versus NOx Emissions

0 50 100 150 200 250 300 350 400 450

0 200 400 600 800 1,000 1,200 1,400 NOx (ppmvd at 15% O2)CO (ppmvd at 15% O2) 1999 CSU-GMC - OCC

1999 CSU-GMC - PCC

1999 CSU-GMC - MSOCC

1999 CSU-EPA - PCC

2009 CSU-PRCI - PCC

Figure 1. CSU engine standard configurations emiss ion data; CO vs. NOx emissions.

For context, the NOx emission levels in Figure 1 ca n be compared to published emission factors for 2SLB engines. For example, in the NOx SIP Call Phase 2 Rule, EPA determined that a NOx emission factor of 16.8 g/bhp-hr is representative of uncontrolled gas transmission reciprocating engines. This equates to approximately 1,100 to 1, 200 ppmv NOx (at 15% O 2 ) for typical 2SLB engine efficiency. The EPA AP-42 document presents uncontrolled NOx emission factors for load above 90% and a separate factor for load less than 90%. At the higher load, the AP-42 NOx emission factor (presented in lb/MMBtu) is approxim ately 850 ppmv and at lower load the emission factor is approximately 500 ppm. The CO e mission factors are approximately 170 and 155 ppmv, respectively. This indicates that higher NOx levels introduced by supplementing dataTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

28 from the EPA sponsored CSU tests with additional CS U test data are well within expected ranges. In addition, as one might expect, the CO e missions from the CSU engine, a “best performing” MACT floor unit, are lower than the AP- 42 emission factors for comparable NOx levels.

In addition, when only considering the CO data from the EPA-sponsored tests, the lowest CO point was 73 ppmv (at 15% O 2 ). CO data from other tests as low as 58 ppmv are marginally lower, which firmly establishes the CSU engine in t he MACT floor. As shown in Table 3, the MACT floor cut point is 69 ppmv or only slightly lo wer than the lowest CO from the EPA tests. Considering measurement accuracy, the MACT floor cu t point and 73 ppmv measured during the EPA tests are essentially the same; this agreement indicates that the CSU engine is effectively a “MACT floor” unit based solely on the EPA results. However, the additional test data further support the range of emissions and emissions variab ility for the CSU Cooper GMV-4TF engine.

As shown in Table 5 and Figure 1, CO emissions are as high as 407 ppmv, with several tests in the range of 240 to 407 ppmv. For EPA sponsored te sts in this range (Test Points 3 and 2-7), these are lower load operation tests with commensur ate lower peak combustion temperatures resulting in low NOx and higher CO. For other test s with higher CO, the engine was configured with the standard pre-combustion chamber technology and air flow was marginally leaner at the highest emitting point, but within common PCC opera tions. The engine configuration and operation were consistent with a unit complying wit h a low NOx emission limit.

While higher load operation is generally preferable and inherent to pipeline systems operating principles, response to pipeline demands requires o perational flexibility and lower load operation. Thus, reciprocating engines have histor ically operated and will continue to operate across the load range under standard operating scen arios. With lower load and variations in other conditions such as excess air (or “turbo boos t”) significantly under-represented in the available data, special consideration of test resul ts associated with those typical conditions is warranted when assessing emissions variability. In addition, the CSU data shows that lower load results in higher CO emissions, and the lowest load available from CSU test data is well over 50% - i.e., higher than loads that recur in normal operation. Based on the available data for MACT floor engines, the test data from the CSU engi ne best captures the range of operating conditions that are likely to recur, and those emis sion bounds should be a primary consideration for the variability assessment. Similar to 4SLB en gines, the data from 2SLB engines support a standard of approximately 400 ppm or higher.

5.0 Conclusions and Recommendations
This report provides historical CO emissions data c ollected by INGAA. In general, test requirements for existing reciprocating engines hav e been driven by NOx concerns; thus, the operating conditions for the INGAA CO data are pred ominantly high load. Since CO tends to increase at lower load for existing lean burn engin es, this limitation in the dataset (i.e. underrepresentation of low load emission data) is an imp ortant consideration when assessing variability.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

29 MACT floor engines and associated data are discusse d in Sections 3 and 4, and the test data are tabulated in the Appendices. INGAA review of MACT floor implications are based on the principles discussed in Section 2. After the best performing units are identified, limitations in the dataset should be recognized when assessing var iability. For both the 4SLB and 2SLB engine subcategories, low load data are limited. H owever, for each subcategory, there is a MACT floor engine that provides data over a broader range of conditions than the majority of the units that have either limited tests or multiple te sts at higher load.

The D.C. Circuit Court has indicated that variabili ty among MACT floor units can be considered when establishing the emission standard, because th e units must meet NESHAP standards at all times and under adverse operating conditions. Thus , it is reasonable to consider emissions associated with adverse operating conditions that a re likely to recur. That variability is likely under-estimated in the INGAA data set because the e missions data are not based on a project or testing designed to characterize variability, and c ommon operating conditions associated with parameters such as reduced load or marginally highe r excess air are not adequately represented by the data. Because of the data limitations, the emissions data from some MACT floor engines may provide more insight than others when consideri ng variability.

For both the 4SLB and 2SLB engine subcategories, a specific engine with data available from broader test conditions is discussed in the report. Data from both of these engines indicate that emissions variability warrants CO standards over 37 0 ppmv (at 15% O 2 ) for both 4SLB and 2SLB engines. For context, comparing this level to the “best demonstrated technology” basis for lean burn engines under the NSPS, indicates that th ese existing engines would have a CO standard similar to or more stringent than a new, N SPS affected engine.

In addition, while the body of the report focuses o n MACT floor engines, the complete data sets in Appendix A and Appendix B indicate that many eng ines will not readily achieve this standard, and action will be required. This could introduce new complexities. Add-on control technology (an oxidation catalyst) is challenged by the relati vely low exhaust temperature for 2SLB engines, and low load and low NOx conditions most conducive to higher CO are also the conditions with the lowest exhaust temperatures. These implication s should also be considered when establishing the standard and ensuring that variabi lity is adequately addressed.

Finally, if variability is properly accounted for, then subcategories may not be necessary and added complexity could be avoided. If INGAA recomm endations to properly consider CO emissions data associated with tests under more adv erse operating conditions are not adopted in the EPA analysis, and EPA concludes that lower stan dards properly assess variability, then INGAA recommends that additional subcategories be c onsidered. There are different types of engines within both the 4SLB and 2SLB subcategories due to design and technology differences such as engine cylinder displacement (which EPA has used in other engine rules), NOx control configuration, air handling, and scavenging design for 2SLB engines. This report introduces some of these issues but detailed documentation is not provided on additional subcategories. If needed, INGAA can provide additional background doc umentation on the technical basis that establishes different engine types for developing m ore refined subcategories.Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor

April 2010

30 APPENDICES

Appendix A: Four-Stroke Lean Burn Engine CO Emissi ons Test Data
Appendix A-1: 4SLB Engine CO Emissions Data for MA CT Floor Engines
Appendix A-2: 4SLB Engine CO Emissions Data for Eng ines not in the MACT Floor

Appendix B: Two-Stroke Lean Burn Engine CO Emissio ns Test Data
Appendix B-1: 2SLB Engine CO Emissions Data for IN GAA MACT Floor Engines
Appendix B-2: 2SLB Engine Emissions Data Summary f or CSU GMV-4TF Engine
Appendix B-3: 2SLB Engine CO Emissions Data for En gines not in the MACT FloorTechnical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

31 

### APPENDIX A-1: 4SLB Engine CO Emissions Data for MA CT Floor Engines

Engine ID No. Engine Make Model Rated Load (hp) Test No. Run No. Test Date Test

Load (hp) %O 2 CO

(ppmv at 15% O 2 ) Avg

CO 1

4S-1 Ingersoll-Rand 512 KVS 2,500 5 1 10/31/1999 2442 10.1 115 4S-1 Ingersoll-Rand 512 KVS 2,500 5 2 10/31/1999 2420 10.0 114 4S-1 Ingersoll-Rand 512 KVS 2,500 5 3 10/31/1999 2413 10.0 113 114

4S-1 Ingersoll-Rand 512 KVS 2,500 7 1 10/2/2000 237 4 10.7 126 4S-1 Ingersoll-Rand 512 KVS 2,500 7 2 10/2/2000 237 5 10.7 126 4S-1 Ingersoll-Rand 512 KVS 2,500 7 3 10/2/2000 239 2 10.7 125 126

4S-1 Ingersoll-Rand 512 KVS 2,500 3 1 11/4/1998 242 3 11.0 139 4S-1 Ingersoll-Rand 512 KVS 2,500 3 2 11/4/1998 245 7 11.1 125 4S-1 Ingersoll-Rand 512 KVS 2,500 3 3 11/4/1998 247 0 11.2 129 131

4S-1 Ingersoll-Rand 512 KVS 2,500 1 1 10/22/1997 2357 11.1 148 4S-1 Ingersoll-Rand 512 KVS 2,500 1 2 10/22/1997 2397 11.4 134 4S-1 Ingersoll-Rand 512 KVS 2,500 1 3 10/22/1997 2455 11.4 134 139

4S-1 Ingersoll-Rand 512 KVS 2,500 8 1 5/31/2001 250 1 10.3 146 4S-1 Ingersoll-Rand 512 KVS 2,500 8 2 5/31/2001 249 0 10.3 146 146

4S-1 Ingersoll-Rand 512 KVS 2,500 4 1 4/28/1999 239 6 10.9 151 4S-1 Ingersoll-Rand 512 KVS 2,500 4 2 4/28/1999 239 0 10.9 152 4S-1 Ingersoll-Rand 512 KVS 2,500 4 3 4/28/1999 238 4 11.0 155 153

4S-1 Ingersoll-Rand 512 KVS 2,500 6 1 4/4/2000 2087 11.2 165 4S-1 Ingersoll-Rand 512 KVS 2,500 6 2 4/4/2000 2087 11.2 162 4S-1 Ingersoll-Rand 512 KVS 2,500 6 3 4/4/2000 2088 11.2 162 163

4S-1 Ingersoll-Rand 512 KVS 2,500 16 1 9/14/2009 24 70 11.6 178 4S-1 Ingersoll-Rand 512 KVS 2,500 16 2 9/14/2009 24 72 11.6 179 178

4S-1 Ingersoll-Rand 512 KVS 2,500 14 1 9/3/2008 244 1 11.1 185 4S-1 Ingersoll-Rand 512 KVS 2,500 14 2 9/3/2008 244 3 11.1 186 185

4S-1 Ingersoll-Rand 512 KVS 2,500 13 1 10/2/2007 24 28 11.5 187 4S-1 Ingersoll-Rand 512 KVS 2,500 13 2 10/2/2007 24 33 11.5 186 186

4S-1 Ingersoll-Rand 512 KVS 2,500 15 1 5/14/2009 22 05 11.6 191 4S-1 Ingersoll-Rand 512 KVS 2,500 15 2 5/14/2009 22 01 11.6 193 192

4S-1 Ingersoll-Rand 512 KVS 2,500 9 1 3/30/2005 195 9 12.2 201 4S-1 Ingersoll-Rand 512 KVS 2,500 9 2 3/30/2005 201 9 12.2 202 201

4S-1 Ingersoll-Rand 512 KVS 2,500 10 1 9/21/2005 24 28 11.3 203 4S-1 Ingersoll-Rand 512 KVS 2,500 10 2 9/21/2005 24 77 11.3 205 204

4S-1 Ingersoll-Rand 512 KVS 2,500 2 1 4/23/1998 235 0 12.4 285 4S-1 Ingersoll-Rand 512 KVS 2,500 2 2 4/23/1998 231 1 11.1 168 4S-1 Ingersoll-Rand 512 KVS 2,500 2 3 4/23/1998 227 5 11.1 171 208

4S-1 Ingersoll-Rand 512 KVS 2,500 12 1 4/18/2007 19 89 12.1 214 4S-1 Ingersoll-Rand 512 KVS 2,500 12 2 4/18/2007 20 00 12.1 209 212

4S-1 Ingersoll-Rand 512 KVS 2,500 11 1 4/12/2006 24 97 11.4 216 214Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

32 4S-1 Ingersoll-Rand 512 KVS 2,500 11 2 4/12/2006 24 99 11.5 213
4S-2 Cooper-Bessemer LSV-16SG 4,400 1 1 2/25/2010 4,205 15.3 113
4S-2 Cooper-Bessemer LSV-16SG 4,400 1 2 2/25/2010 4,278 15.0 132 123

4S-2 Cooper-Bessemer LSV-16SG 4,400 1 3 2/25/2010 3,716 15.5 134 134
4S-2 Cooper-Bessemer LSV-16SG 4,400 1 4 2/25/2010 3,347 13.2 140 140 4S-3 Ingersoll-Rand 36 KVS 1,000 2 1 4/23/1998 963 10.9 124 4S-3 Ingersoll-Rand 36 KVS 1,000 2 2 4/23/1998 964 10.9 126 4S-3 Ingersoll-Rand 36 KVS 1,000 2 3 4/23/1998 963 10.8 122 124

4S-3 Ingersoll-Rand 36 KVS 1,000 6 1 4/4/2000 843 1 0.9 128 4S-3 Ingersoll-Rand 36 KVS 1,000 6 2 4/4/2000 846 1 0.8 126 4S-3 Ingersoll-Rand 36 KVS 1,000 6 3 4/4/2000 846 1 0.8 125 126

4S-3 Ingersoll-Rand 36 KVS 1,000 5 1 10/31/1999 1044 10.7 127 4S-3 Ingersoll-Rand 36 KVS 1,000 5 2 10/31/1999 1041 10.7 127 4S-3 Ingersoll-Rand 36 KVS 1,000 5 3 10/31/1999 1037 10.7 128 127

4S-3 Ingersoll-Rand 36 KVS 1,000 7 1 10/2/2000 1003 11.4 141 4S-3 Ingersoll-Rand 36 KVS 1,000 7 2 10/2/2000 1002 11.4 139 4S-3 Ingersoll-Rand 36 KVS 1,000 7 3 10/2/2000 1003 11.3 139 140

4S-3 Ingersoll-Rand 36 KVS 1,000 16 1 8/25/2009 936 10.8 142 4S-3 Ingersoll-Rand 36 KVS 1,000 16 2 8/25/2009 933 10.8 146 144

4S-3 Ingersoll-Rand 36 KVS 1,000 14 1 9/3/2008 966 11.0 153 4S-3 Ingersoll-Rand 36 KVS 1,000 14 2 9/3/2008 964 11.0 153 153

4S-3 Ingersoll-Rand 36 KVS 1,000 1 1 10/22/1997 993 11.2 155 4S-3 Ingersoll-Rand 36 KVS 1,000 1 2 10/22/1997 974 11.2 155 4S-3 Ingersoll-Rand 36 KVS 1,000 1 3 10/22/1997 967 11.3 161 157

4S-3 Ingersoll-Rand 36 KVS 1,000 10 1 9/21/2005 970 11.5 163 4S-3 Ingersoll-Rand 36 KVS 1,000 10 2 9/21/2005 998 11.5 163 163

4S-3 Ingersoll-Rand 36 KVS 1,000 11 1 4/12/2006 906 11.7 168 4S-3 Ingersoll-Rand 36 KVS 1,000 11 2 4/12/2006 907 11.7 164 166

4S-3 Ingersoll-Rand 36 KVS 1,000 3 1 11/3/1998 950 11.3 165 4S-3 Ingersoll-Rand 36 KVS 1,000 3 2 11/3/1998 926 11.4 166 4S-3 Ingersoll-Rand 36 KVS 1,000 3 3 11/3/1998 910 11.5 176 169

4S-3 Ingersoll-Rand 36 KVS 1,000 8 1 5/30/2001 987 11.8 170 4S-3 Ingersoll-Rand 36 KVS 1,000 8 2 5/30/2001 980 11.8 170 170

4S-3 Ingersoll-Rand 36 KVS 1,000 9 1 3/30/2005 798 11.3 169 4S-3 Ingersoll-Rand 36 KVS 1,000 9 2 3/30/2005 799 11.4 176 172

4S-3 Ingersoll-Rand 36 KVS 1,000 13 1 10/2/2007 951 11.4 180 4S-3 Ingersoll-Rand 36 KVS 1,000 13 2 10/2/2007 955 11.4 179 179

4S-3 Ingersoll-Rand 36 KVS 1,000 15 1 5/14/2009 860 11.5 203 4S-3 Ingersoll-Rand 36 KVS 1,000 15 2 5/14/2009 862 11.5 205 204

4S-3 Ingersoll-Rand 36 KVS 1,000 4 1 4/27/1999 960 11.5 224 4S-3 Ingersoll-Rand 36 KVS 1,000 4 2 4/27/1999 954 11.6 233 4S-3 Ingersoll-Rand 36 KVS 1,000 4 3 4/27/1999 952 11.6 241 233Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

33 4S-3 Ingersoll-Rand 36 KVS 1,000 12 1 4/18/2007 799 11.8 274 4S-3 Ingersoll-Rand 36 KVS 1,000 12 2 4/18/2007 799 11.8 267 270

4S-4 Ingersoll-Rand KVH- 616 4,200 13 1 8/4/1999 3489 9.87 128 128
4S-4 Ingersoll-Rand KVH- 616 4,200 10 1 8/4/1999 3175 9.89 128 128
4S-4 Ingersoll-Rand KVH- 616 4,200 9 1 8/4/1999 2958 9.94 131 131
4S-4 Ingersoll-Rand KVH- 616 4,200 12 1 8/4/1999 3169 10.19 152 152
4S-4 Ingersoll-Rand KVH- 616 4,200 3 1 8/22/1995 3243 10.27 152 152
4S-4 Ingersoll-Rand KVH- 616 4,200 6 1 8/22/1995 3801 10.29 160 160
4S-4 Ingersoll-Rand KVH- 616 4,200 1 1 8/22/1995 4209 10.29 160 160
4S-4 Ingersoll-Rand KVH- 616 4,200 11 1 8/4/1999 2881 10.49 162 162
4S-4 Ingersoll-Rand KVH- 616 4,200 4 1 8/22/1995 2950 11.10 205 205
4S-4 Ingersoll-Rand KVH- 616 4,200 5 1 8/22/1995 2777 11.10 205 205
4S-4 Ingersoll-Rand KVH- 616 4,200 8 1 8/4/1999 2393 11.11 223 223
4S-4 Ingersoll-Rand KVH- 616 4,200 7 1 8/22/1995 4007 11.12 240 240
4S-4 Ingersoll-Rand KVH- 616 4,200 2 1 8/22/1995 3229 11.12 240 240 4S-5 Ingersoll-Rand 512 KVS 2,000 3 1 11/4/1998 196 7 11.6 127 4S-5 Ingersoll-Rand 512 KVS 2,000 3 2 11/4/1998 193 9 11.6 130 4S-5 Ingersoll-Rand 512 KVS 2,000 3 3 11/4/1998 191 7 11.7 136 131

4S-5 Ingersoll-Rand 512 KVS 2,000 5 1 10/30/1999 1949 11.5 155 4S-5 Ingersoll-Rand 512 KVS 2,000 5 2 10/30/1999 1957 11.5 155 4S-5 Ingersoll-Rand 512 KVS 2,000 5 3 10/30/1999 1962 11.4 153 154

4S-5 Ingersoll-Rand 512 KVS 2,000 4 1 4/28/1999 191 0 11.5 152 4S-5 Ingersoll-Rand 512 KVS 2,000 4 2 4/28/1999 190 4 11.5 158 4S-5 Ingersoll-Rand 512 KVS 2,000 4 3 4/28/1999 190 1 11.6 158 156

4S-5 Ingersoll-Rand 512 KVS 2,000 15 1 5/14/2009 18 20 11.8 157 4S-5 Ingersoll-Rand 512 KVS 2,000 15 2 5/14/2009 18 13 11.9 158 157

4S-5 Ingersoll-Rand 512 KVS 2,000 1 1 10/22/1997 1922 11.6 164 4S-5 Ingersoll-Rand 512 KVS 2,000 1 2 10/22/1997 1961 11.6 164 4S-5 Ingersoll-Rand 512 KVS 2,000 1 3 10/22/1997 1998 11.6 154 161

4S-5 Ingersoll-Rand 512 KVS 2,000 14 1 9/3/2008 190 3 11.9 166 4S-5 Ingersoll-Rand 512 KVS 2,000 14 2 9/3/2008 190 2 11.9 164 165

4S-5 Ingersoll-Rand 512 KVS 2,000 10 1 9/21/2005 19 42 11.6 172 4S-5 Ingersoll-Rand 512 KVS 2,000 10 2 9/21/2005 19 53 11.5 165 168

4S-5 Ingersoll-Rand 512 KVS 2,000 12 1 4/18/2007 16 72 12.2 169 4S-5 Ingersoll-Rand 512 KVS 2,000 12 2 4/18/2007 16 67 12.2 170 170

4S-5 Ingersoll-Rand 512 KVS 2,000 13 1 10/2/2007 19 62 11.8 170 4S-5 Ingersoll-Rand 512 KVS 2,000 13 2 10/2/2007 19 58 11.8 169 170

4S-5 Ingersoll-Rand 512 KVS 2,000 16 1 8/25/2009 20 15 11.5 177 4S-5 Ingersoll-Rand 512 KVS 2,000 16 2 8/25/2009 20 03 11.5 177 177

4S-5 Ingersoll-Rand 512 KVS 2,000 9 1 3/30/2005 167 4 11.8 186 4S-5 Ingersoll-Rand 512 KVS 2,000 9 2 3/30/2005 166 0 11.8 183 185

4S-5 Ingersoll-Rand 512 KVS 2,000 11 1 4/12/2006 20 40 11.4 185 185Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

34 4S-5 Ingersoll-Rand 512 KVS 2,000 11 2 4/12/2006 20 35 11.4 184 4S-5 Ingersoll-Rand 512 KVS 2,000 8 1 5/31/2001 196 9 11.3 190 4S-5 Ingersoll-Rand 512 KVS 2,000 8 2 5/31/2001 197 2 11.3 197 194

4S-5 Ingersoll-Rand 512 KVS 2,000 7 1 10/2/2000 203 7 11.6 211 4S-5 Ingersoll-Rand 512 KVS 2,000 7 2 10/2/2000 203 5 11.5 212 4S-5 Ingersoll-Rand 512 KVS 2,000 7 3 10/2/2000 202 8 11.5 212 212

4S-5 Ingersoll-Rand 512 KVS 2,000 6 1 4/4/2000 1626 11.8 218 4S-5 Ingersoll-Rand 512 KVS 2,000 6 2 4/4/2000 1628 11.8 214 4S-5 Ingersoll-Rand 512 KVS 2,000 6 3 4/4/2000 1628 11.8 211 214

4S-5 Ingersoll-Rand 512 KVS 2,000 2 1 4/28/1998 171 4 12.3 207 4S-5 Ingersoll-Rand 512 KVS 2,000 2 2 4/28/1998 169 1 12.6 229 4S-5 Ingersoll-Rand 512 KVS 2,000 2 3 4/28/1998 166 6 12.6 243 226

4S-6 Cooper-Bessemer LSV-16SG 4,400 2 3 2/26/2010 4,323 9.6 135 135
4S-6 Cooper-Bessemer LSV-16SG 4,400 2 1 2/26/2010 3,550 10.3 137 137
4S-6 Cooper-Bessemer LSV-16SG 4,400 2 2 2/26/2010 3,975 9.9 144 144 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 3 1 3/23/2006 9 90 11.8 137 137 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 8 1 3/23/2006 8 72 11.0 175 175 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 10 1 3/23/2006 675 10.9 178 178 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 5 1 3/23/2006 8 53 12.1 182 182 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 11 1 3/23/2006 571 11.2 182 182 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 7 1 3/23/2006 7 96 11.0 200 200 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 4 1 3/23/2006 9 26 12.2 202 202 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 6 1 3/23/2006 7 25 11.9 207 207 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 9 1 3/23/2006 7 52 11.2 213 213 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 1 1 3/22/2006 5 73 12.4 230 230 4S-7 Ingersoll-Rand 36 KVS-FT 1,000 2 1 3/22/2006 4 72 13.4 375 375
4S-8 Ingersoll-Rand 36 KVS 1,000 5 1 10/31/1999 983 10.4 136
4S-8 Ingersoll-Rand 36 KVS 1,000 5 2 10/31/1999 981 10.4 140
4S-8 Ingersoll-Rand 36 KVS 1,000 5 3 10/31/1999 976 10.5 140 139

4S-8 Ingersoll-Rand 36 KVS 1,000 7 1 10/2/2000 986 11.2 166
4S-8 Ingersoll-Rand 36 KVS 1,000 7 2 10/2/2000 986 11.3 166
4S-8 Ingersoll-Rand 36 KVS 1,000 7 3 10/2/2000 987 11.2 166 166

4S-8 Ingersoll-Rand 36 KVS 1,000 14 1 9/3/2008 965 11.4 170
4S-8 Ingersoll-Rand 36 KVS 1,000 14 2 9/3/2008 968 11.4 170 170

4S-8 Ingersoll-Rand 36 KVS 1,000 11 1 4/12/2006 911 11.7 172
4S-8 Ingersoll-Rand 36 KVS 1,000 11 2 4/12/2006 908 11.6 172 172

4S-8 Ingersoll-Rand 36 KVS 1,000 13 1 10/2/2007 977 11.6 173
4S-8 Ingersoll-Rand 36 KVS 1,000 13 2 10/2/2007 977 11.6 171 172

4S-8 Ingersoll-Rand 36 KVS 1,000 16 1 8/25/2009 938 11.5 168
4S-8 Ingersoll-Rand 36 KVS 1,000 16 2 8/25/2009 936 11.5 176 172

4S-8 Ingersoll-Rand 36 KVS 1,000 10 1 9/21/2005 955 11.5 178
4S-8 Ingersoll-Rand 36 KVS 1,000 10 2 9/21/2005 950 11.5 178 178Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

35 4S-8 Ingersoll-Rand 36 KVS 1,000 2 1 4/28/1998 705 10.6 186
4S-8 Ingersoll-Rand 36 KVS 1,000 2 2 4/28/1998 706 10.6 188
4S-8 Ingersoll-Rand 36 KVS 1,000 2 3 4/28/1998 706 10.3 166 180

4S-8 Ingersoll-Rand 36 KVS 1,000 8 1 5/30/2001 984 11.7 181
4S-8 Ingersoll-Rand 36 KVS 1,000 8 2 5/30/2001 981 11.8 185 183

4S-8 Ingersoll-Rand 36 KVS 1,000 6 1 4/4/2000 802 11.2 185
4S-8 Ingersoll-Rand 36 KVS 1,000 6 2 4/4/2000 799 11.2 186
4S-8 Ingersoll-Rand 36 KVS 1,000 6 3 4/4/2000 798 11.3 186 186

4S-8 Ingersoll-Rand 36 KVS 1,000 9 1 3/30/2005 763 12.1 196
4S-8 Ingersoll-Rand 36 KVS 1,000 9 2 3/30/2005 761 12.1 189 192

4S-8 Ingersoll-Rand 36 KVS 1,000 1 1 10/22/1997 936 11.3 195
4S-8 Ingersoll-Rand 36 KVS 1,000 1 2 10/22/1997 904 11.3 195
4S-8 Ingersoll-Rand 36 KVS 1,000 1 3 10/22/1997 900 11.3 195 195

4S-8 Ingersoll-Rand 36 KVS 1,000 3 1 11/3/1998 822 11.5 197
4S-8 Ingersoll-Rand 36 KVS 1,000 3 2 11/3/1998 816 11.5 197
4S-8 Ingersoll-Rand 36 KVS 1,000 3 3 11/3/1998 816 11.5 191 195

4S-8 Ingersoll-Rand 36 KVS 1,000 15 1 5/14/2009 859 11.7 205
4S-8 Ingersoll-Rand 36 KVS 1,000 15 2 5/14/2009 856 11.7 203 204

4S-8 Ingersoll-Rand 36 KVS 1,000 12 1 4/18/2007 795 12.0 211
4S-8 Ingersoll-Rand 36 KVS 1,000 12 2 4/18/2007 790 12.1 217 214

4S-8 Ingersoll-Rand 36 KVS 1,000 4 1 4/27/1999 901 12.0 301
4S-8 Ingersoll-Rand 36 KVS 1,000 4 2 4/27/1999 902 11.9 298
4S-8 Ingersoll-Rand 36 KVS 1,000 4 3 4/27/1999 901 11.8 295 298

4S-9 Caterpillar G3516 880 3 1 10/15/2002 785 8.80 142 4S-9 Caterpillar G3516 880 3 2 10/15/2002 785 8.80 141 4S-9 Caterpillar G3516 880 3 3 10/15/2002 785 8.80 139 141

4S-9 Caterpillar G3516 880 5 1 2/20/2003 747 8.50 157 4S-9 Caterpillar G3516 880 5 2 2/20/2003 747 8.50 156 4S-9 Caterpillar G3516 880 5 3 2/20/2003 747 8.50 156 156

4S-9 Caterpillar G3516 880 4 1 12/12/2002 806 9.00 160 4S-9 Caterpillar G3516 880 4 2 12/12/2002 806 9.00 162 4S-9 Caterpillar G3516 880 4 3 12/12/2002 806 9.00 161 161

4S-9 Caterpillar G3516 880 2 1 6/27/2002 861 8.59 190 4S-9 Caterpillar G3516 880 2 2 6/27/2002 861 8.59 191 4S-9 Caterpillar G3516 880 2 3 6/27/2002 861 8.61 189 190

4S-9 Caterpillar G3516 880 1 1 4/12/2002 659 8.39 183 4S-9 Caterpillar G3516 880 1 2 4/12/2002 659 8.37 198 4S-9 Caterpillar G3516 880 1 3 4/12/2002 659 8.33 206 196

4S-10 Ingersoll-Rand KVT- 512 3,000 1 1 10/25/1995 2712 10.23 149 149
4S-10 Ingersoll-Rand KVT- 512 3,000 6 1 12/27/2006 2823 11.50 183
4S-10 Ingersoll-Rand KVT- 512 3,000 6 2 12/27/2006 2812 11.50 180
4S-10 Ingersoll-Rand KVT- 512 3,000 6 3 12/27/2006 2833 11.50 187 183Technical Report: Natural Gas-Fired Engine Emissio ns Data for MACT Floor April 2010

36 4S-10 Ingersoll-Rand KVT- 512 3,000 4 1 10/25/1995 2024 11.26 201 201
4S-10 Ingersoll-Rand KVT- 512 3,000 3 1 10/25/1995 2902 10.61 202 202
4S-10 Ingersoll-Rand KVT- 512 3,000 5 1 4/26/2001 2921 11.97 220 220
4S-10 Ingersoll-Rand KVT- 512 3,000 2 1 10/25/1995 2253 10.62 226 226 4S-11 Ingersoll Rand KVS- 412 ~2,050 1 1 9/13/1995 2,044 12.7 156 4S-11 Ingersoll Rand KVS- 412 ~2,050 1 2 9/13/1995 2,007 12.8 156 4S-11 Ingersoll Rand KVS- 412 ~2,050 1 3 9/13/1995 1,793 12.7 146 153

4S-11 Ingersoll Rand KVS- 412 ~2,050 2 1 3/22/2006 1,962 15.0 219 4S-11 Ingersoll Rand KVS- 412 ~2,050 2 2 3/22/2006 1,943 15.0 224 4S-11 Ingersoll Rand KVS- 412 ~2,050 2 3 3/22/2006 1,946 14.8 225 223

NOTE 1: ppmvd @ 15% O 2 ; Values in column are either multi-run average or value of a single test (i.e., a one run test)