### December 8, 2011

Mr. Gerardo Rios Chief, Permits Office U.S. EPA, Region 9

75 Hawthorne Street San Francisco, CA 94105

Subject: Pio Pico Energy Ce nter PSD Permit Application PM BACT for Simple-Cycle Turbines

Dear Mr. Rios:

As requested by EPA in a telephone convers ation between Roger Kohn (EPA) and Steve Hill (Sierra Research) on November 29, 2011, we are submitting clarifying information on behalf of Pio Pico Energy Center, LLC (Applicant). EPA requested additional analysis to support the determination in the repackaged PSD application of BACT for PM emissions from the simple-cycle turbines.



## Summary of BACT Analysis C ontained in the September 15 th 

## PSD Package

On September 15, 2011, the Applicant submitted a repackaged PSD application. The top-down PM BACT analysis demonstrated that PM/PM 10 

### /PM 2.5 

### BACT for normal operation of the simple-cycle gas turbines is the use of natural gas as the primary fuel source. The Applicant proposed an emission limit of 5.5 lb/hr, based on vendor guarantees and the experience of the Applicant and others with similar installations.

EPA staff also requested confirmation of the sulfur levels used by the Applicant in its emission calculations. The Applicant based its emission calculations on fuel sulfur levels of 0.25 gr/100 scf (annual average) a nd 0.75 gr/100 scf (hourly average). 1



## Control Level

EPA has not indicated that it disagrees with the Applicant’s demonstration that BACT for this project is the use of natural gas as the primary fuel source; but did request additional justification for the proposed compliance limit of 5.5 lb/hr. Additionally, EPA has indicated that the compliance limit should be ex pressed as an emission rate in units of lb/MMbtu (HHV) of heat input.

1 See repackaged PSD Application (September 2011), pp. PSD-4.34, PSD-4.55, and PSD-App-1.53. 

# sierra research

1801 J Street Sacramento, CA 95811 Tel: (916) 444-6666 Fax: (916) 444-8373

Ann Arbor, MI Tel: (734) 761-6666 Fax: (734) 761-6755

### Gerardo Rios, EPA -2- December 8, 2011

Comment : In order to facilitate comparison with other projects, EPA requests that the proposed limit be expressed as an emi ssion rate (in units of lb/MMBtu).

Response: The Applicant’s originally proposed compliance limit of 5.5 lb/hr was intended to apply under all circumstances, in cluding full load, low load, startup, and

shutdown. Because fuel use is different unde r these conditions, the lb/MMBtu rate will

be different as well.

Compliance with the PM limits is demonstrated through the us e of periodic source tests. As specified in 40 CFR 60.8(a)(4)(c), perf ormance tests are conducted “under such conditions as the Administrator shall specify based on representative performance of the affected facility.” The Applicant is willing to accept the emission limit of 0.0065 lb/MMBtu (HHV), which is equivalent to th e Applicant’s proposed limit of 5.5 lb/hr, when the turbine is operated at or near full load. 2 

### Compliance with this limit would be demonstrated by a source test that complies with all of the requirements set forth in 40 CFR § 60.8 and 40 CFR Part 60 Appendix A, conducted at or near full load. 3



### Comment : Please provide additional ju stification for the propos ed limit. Compare with the limits achieved in practice by other gas turbines. Following the top-down BACT procedure, rank the examples from lowest to highest and either explain why they do not apply to the project, or revise your proposedBACT emission rate to reflect achieved-inpractice limits.

Response: Particulate emissions from combustion of natural gas are usually below the

limits of detection of current EPA test methods . As a result, PM test results from gasfired combustion equipment are highly vari able, and are often dominated by testing

artifacts. Differences in PM emission rates proposed for PSD permits are often

attributable to the risk tolera nce of the applicant and/or eq uipment vendor, rather than to any technical specification. Nonetheless, we have reviewed additional PM BACT determinations as requested by EPA.

The sources listed in the attached Table 1 were considered for this analysis. Information

in this table was taken from EPA’s fact sh eet for the Palmdale Hybrid PSD Permit.

The most recently permitted units with total PM limits expressed as lb/MMBtu are Palmdale Hybrid in California (Palmdale) , Warren County Power Station in Virginia (Warren County), and Chouteau Power Plant in Oklahoma (Chouteau). Of these three facilities, only the Chouteau un it is operational. Because neither Palmdale nor Warren County has any operating history, the permit limits are not rele vant to an analysis of achieved-in-practice emission rates. Therefore, all of the sources listed in Table 1, except Chouteau, were eliminated fr om further consideration.

2 0.0065 lb/MMBtu = (5.5 lb/hr) / (851.5MMBtu). The heat rate is the lowest peak fuel use rate from the design cases.

3 EPA Methods 5 and 202, or Methods 201A and 202, for PM, PM 10 , and PM 2.5 , or CTM-039 in lieu of

Method 202.

### Gerardo Rios, EPA -3- December 8, 2011

The new turbines at Chouteau are subject to a PM limit of 0.0035 lb/MMBtu, averaged

over 24 hours. 4 

### Because the source test methodology used to demonstrate compliance is comprised of three test runs that can be as short as one hour each, it is impossible to determine compliance with a 24-hour averag e limit for PM expressed as lb/MMbtu.

PM source tests were conducted at Chout eau on May 18-25, 2011, and again on July 6-8,

2011. 5 

### The results from initial complian ce testing of total PM at Chouteau are summarized in Table 2 (attached). Table 2 s hows that Chouteau did not comply with its PM limits; therefore, this unit does not demonstrate achieved-in-practice BACT.

As shown in the following table, a statisti cal analysis of the Chouteau test results

indicates a mean PM value of 0.0052 lbs/MMbt u, with a relative sta ndard deviation of 30%. Since permit limits must be met on an on-going basis for the lif e of the plant, an analysis of source test data must include an allowance for variability. The mean plus two standard deviations, based on the Chouteau te st data, is 0.0084 lbs/MMbtu; thus, if these are used to establish a permit limit, the limit should be no lower than 0.0084 lbs/MMbtu.

Date 5/25/2011 5/22

‐ 23/2011 5/18/2011 7/7

‐ 8/2011 7/7/2011 7/6/2011 7/6/2011 7/7/2011

Unit 21 22 22 21 21 21 22 33

Unit Load 100% 100% 60% 60% 100% 100% 100% 100%

DB Load 0% 0% 0% 0% 70% 100% 70% 100%

Run 1 0.0036 0.0042 0.0056 0.0054 0.0058 0.0078 0.0082 0.0069

Run 2 0.0029 0.0035 0.0043 0.0055 0.0061 0.0079 0.0080 0.0039

Run 3 0.0035 0.0040 0.0048 0.0043 0.0047 0.0048 0.0061 0.0039

Average 0.0033 0.0039 0.0049 0.0051 0.0055 0.0068 0.0074 0.0049

Overall Average 0.0052

Overall Std Deviation 0.0016

Relative Std Deviation 30%

Mean plus 2 S.D 0.0084 Summary of Chouteau PM Test Results (lbs/MMbtu)



### The PM control level proposed by the Applicant, 0.0065 lb/MMB tu at peak turbine load,

was based on source test data from similar un its operating in Southern California, and is

the lowest emission rate that a ssures continuous compliance. It is lower than the level for which the turbine vendor will provide guarantees , and it is lower than the value suggested by the Chouteau data.

The Applicant’s proposed limit of 0.0065 lbs/MM btu is not applicable to low load operation, startup, or shutdown. We understand that EPA wishes to consider including in the permit an emission rate limit that is appl icable to low load operations. We believe there is insufficient data upon which to establ ish a low-load emissi on rate (in units of

4 Oklahoma DEQ Permit No. 2007-115-C (M-1) PSD, Condition 1, limits PM 10 emissions from Turbines EU 1-03 and 1-04 to 6.24 lb/hr (3-hour average, without duct firing), 6.59 lb/hr (3-hour average, with duct firing) and 0.0035 lb/MMBtu (24-hour average).

5 Letter, dated August 19, 2011 from Tadd Henry (Associated Electric Cooperative) to Kendal Stegman (Oklahoma DEQ).

### Gerardo Rios, EPA -4- December 8, 2011

lbs/hr) different from that a pplicable at maximum load. B ecause the hourly emissions are expected to be about the same for the Pio Pi co Energy Center turbines (5.5 lb/hr) at all loads, the highest emission rate (in lbs/MMbtu) will occur at the lowest fuel usage, or low load. While each turbine will normally operate at close to full load when it is operating, each turbine is expected to operate at load s as low as 50% on occasion. The expected

emission rate at low load is 0.01 lb/MMBtu. 6



### If you have any questions regarding this in formation, please contact the Applicant’s representative David Jenkins at (317) 431-1004, or Gary Rubenstein or me at (916) 444-6666.

Sincerely,

Steve Hill

cc: John McKinsey, Stoel Rives LLP David Jenkins, Apex Power Group
Steve Moore, SDAPCD

6 0.01 lb/MMBtu = (5.5 lb/hr) / (542.5MMBtu). This heat input rate is the lowest low load fuel use rate from the design cases.Table 1Summary of Recent PM BACT Limits for Combined-Cycle, NaturalGas-Fired Combustion TurbinesFacility LocationPM LimitWithout DuctFiringType of PMFilterable (F)Total (T)Averagingperiod Control Permit Issuance Source Basis for ExcludingPio Pico Energy Center California 5.5 lb/hr,0.0065lb/MMBtuTPM10,TPM2.53-hour Natural Gas Fuel This Application PSD Permit ApplicationAvenal Energy Project California 8.91 lb/hr TPM10 12-monthrollingNatural Gas Fuel June 2011 PSD Permit Not yet constructed; notlb/MMBtuWarren County PowerStationVirginia 0.0027lb/MMBtuTPM10, TPM2.5 3-hour -- December 2010 PSD Permit No operating dataCarty Plant Oregon 2.5 lb/MMscf FPM10 -- Clean FuelDraft December 2010 RBLC #OR-0048 Not yet constructed;Filterable PMLangley Gulch PowerPlantIdaho No limit FPM10 -- GCPDraft December 2010 RBLC # ID-0018 Not yet constructed;Filterable PMColusa GeneratingStationCalifornia 13.5 lb/hour TPM, TPM10 12-monthrollingNatural Gas Fuel March 2010 PSD Permit No operating data; notlb/MMBtuVictorville II HybridPower ProjectCalifornia 12.0 lb/hr TPM, TPM2.5 12-monthrollingNatural Gas Fuel March 2010PSD Permit Not lb/MMBtuChouteau Power Plant Oklahoma 0.0035lb/MMBtuTPM10 3-hour Natural Gas Fuel January 2009RBLC # OK-0129 Not in compliance withconditionsCane Island Power Park Florida 2 gr S/100 SCF TPM10 -- FuelSpec September 2008 RBLC # FL-0304 Fuel specification, notsource testFPL West CountyEnergy Center Unit 3Florida 2 gr S/100 SCF PM,PM19/PM2.5Clean Fuel July 2008 RBLC #LA-0136 Fuel specification, notsource testPlaquemineCogeneration FacilityLouisiana 0.02 lb/MMBtu FPM10,TPM -- Clean FuelJuly 2008 RBLC #LA-0136 Less stringent than PPECArsenal Hill Power Plant Louisiana 24.23 lb/hrFPM -- Pipeline NaturalGasMarch 2008 RBLC # LA-0224 Filterable PMKleen Energy Systems Connecticut 11 lb/hr FPM10 -- -- February 2008 RBLC # CT-0151 Filterable PMPalmdale Hybrid California 0.0048lb/MMBtuTPM 9-hour Better-than-PUCquality natural gasOctober 2011 PSD Permit Not yet constructedTable 22011 Chouteau Source Test ResultsDate UnitCTLoad(%)DBLoad(%)Particulate Emissions(lb/hr)aPermitLimit(lb/hr)Particulate Emissions(lb/MMbtu)aPermit Limit(lb/MMbtu)May 25 21 100 06.01 4.70 5.566.240.0036 0.0029 0.00350.00355.42 0.0033May 18 22 60 06.97 5.41 6.156.240.0056 0.0043 0.00480.00356.180.0049May 22-23 22 100 07.09 5.68 6.526.240.0042 0.0035 0.00400.00356.430.0039July 7-8 21 60 06.68 6.63 5.336.240.0054 0.0055 0.00430.00356.210.0051July 7 21 100 7010.4 11.1 8.586.590.0058 0.0061 0.00470.003510.00.0055July 6 21 100 10014.6 14.9 8.536.590.0078 0.0079 0.00480.003512.70.0068July 6 22 100 7014.8 14.2 10.96.590.0082 0.0080 0.00610.003513.30.0074July 7 22 100 10012.8 7.35 7.236.590.0069 0.0039 0.00390.00359.130.0049aIndividual test run results shown in top row; three-run average shown in bold in bottom row.Three-run averages highlighted inyellow exceed applicable limit.