March 19, 2012 

Mr. Gerardo Rios 

Chief, Permits Office 

U.S. EPA Region 9 

75 Hawthorne Street 

San Francisco, CA 94105 

Subject: Pio Pico Energy Center PSD Permit Application 

 Response to Supplemental Information Request 

 

Dear Mr. Rios: 

As requested by EPA during the February 13, 2012 conference call between 

representatives of EPA and Pio Pico Energy Center, LLC (Applicant), we are submitting 

this additional information on behalf of Applicant. 

Proposed Language for GHG BACT 

Comment: It is known that turbine efficiency tends to decrease over the lifetime of the 

turbine, even under the best of circumstances. If EPA imposed a single numerical limit 

that would apply to the turbine over its lifetime, it would either be too low for a new unit, 

or too high for a unit at the end of its life cycle, or both. EPA is therefore considering 

defining GHG BACT as an initial demonstration of turbine efficiency, coupled with 

ongoing maintenance. Please provide suggested language for EPA’s consideration. 

Response: Applicant proposes the following language: 

1. GHG BACT requirements 

a. Performance Test 

i. Within 60 days after achieving normal operation, but not later than 

180 days after the initial startup of equipment, Permittee shall 

conduct a performance test to demonstrate the thermal efficiency 

(btuhhv/kw-hrnet) of each turbine at maximum capacity. Each 

turbine shall meet one of the following requirements, depending 

upon the conditions at the time of the test: 

1. Less than 8,647 btu/kw-hr below 30oF ambient 

temperature; or 

2. Less than 8,747 btu/kw-hr between 30oF and 63oF ambient 

temperature; or 

3. Less than 8,929 btu/kw-hr between 63oF and 110oF ambient 

temperature. 

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 -2- March 19, 2012 

b. Monitoring 

i. Permittee shall measure and record, for each turbine, the 

following: 

1. Net energy output (MWhnet) on an hourly basis 

2. Fuel consumption (MMSCF of natural gas) on an hourly 

basis 

c. Maintenance requirements 

i. Permittee shall maintain each turbine, including associated air 

pollution control equipment and monitoring equipment, in a 

manner consistent with safety and good air pollution control 

practices for minimizing emissions. 

ii. Permittee shall prepare a Maintenance Plan for each turbine. The 

Maintenance Plan shall follow manufacturer’s written instructions 

or operator-developed procedures that provide, to the extent 

practicable, for the maintenance and operation of the engine in a 

manner consistent with good air pollution control practice for 

minimizing emissions. 

iii. Permittee shall maintain each turbine according to the Maintenance 

Plan. 

d. Recordkeeping requirements 

i. Permittee shall maintain a log describing maintenance and repair 

activities, including the following information: 

1. Date of activity 

2. Description of activity 

3. For scheduled maintenance, the elapsed time, hours of 

turbine operation, or other applicable measure since the 

activity was last performed. 

4. For scheduled maintenance, the elapsed time, hours of 

turbine operation, or other applicable measure until the 

activity should next be performed. 

The proposed thermal efficiency limits are based on GE performance projections for 

clean and new equipment at the upper end of each temperature range. 

Summary of PM2.5 NAAQS Compliance Calculation 

Comment: Please show the calculations and relevant data used to demonstrate 

compliance with the 24-hour and annual PM2.5 NAAQS. 

Response: The requested calculations are presented in Tables 1 and 2 for the 24-hour and 

annual average standards, respectively. Compliance with the 24-hour standard is 

demonstrated using the receptor with the highest five-year average of 98th percentile of 

cumulative impacts (project plus nearby sources plus background). 
Gerardo Rios -3- March 19, 2012 

Table 1 

24-hr PM2.5 NAAQS Compliance Calculation (μg/m3) 

Data are for 98th percentile day for each year 

Standard = 35 μg/m3

Year 2004 2005 2006 2007 2008 

Five-Year 

Average 

Date March 20 March 11 Feb. 26 Nov. 8 Jan. 10 

Project Impact 

(μg/m3

) 0.2 0.2 0.1 0.3 0.3 0.2

Cumulative 

Impact (μg/m3

) 0.8 0.5 0.5 0.9 0.9 0.7

Regional 

Background 

(μg/m3

) 

30.0 28.0 24.0 27.0 26.0 27.0

Total Impact 

with 

Background 

30.8 28.5 24.5 27.9 26.9 27.7

Compliance with the annual standard is demonstrated using a screening approach, where 

the highest background value in the five-year period is added to the highest cumulative 

impact. Because the result is below the standard, more refined calculations were not 

made. 

Table 2 

Annual PM2.5 NAAQS Compliance Calculation (μg/m3

) 

Standard = 15 μg/m3

Year 2004 2005 2006 2007 2008 Maximum 

Background 12.2 11.8 11.2 12.5 12.3 12.5 

Cumulative Max 1.4 1.5 1.5 1.6 1.9 1.9 

Total 14.4 

Sincerely, 

Steve Hill 

cc: John McKinsey, Stoel Rives LLP 

David Jenkins, Apex Power Group 

 Steve Moore, SDAPCD