UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION IX
 

75 Hawthorne Street
 

San Francisco, CA 94105
 

July 18,2011 

Mr. George L. Piantka, P.E. 

NRG Energy Inc. - West Region 

5790 Fleet Street, Suite 200 

Carlsbad, California 92008 

Subject: New PSD Applicability Determination Analysis for the Carlsbad Energy Center Power 

Project 

Dear Mr. Piantka: 

This letter is to inform you that the United Stated Environmental Protection Agency (EPA) is 

withdrawing as moot the Prevention of Significant Deterioration (PSD) applicability determination for 

the Carlsbad Energy Center Project (CECP) previously issued on October 13, 2010 and January 11, 

2011. The analysis contained in that applicability determination was based on a projected actual 

construction date of June 30, 2011, and clearly stated that if "the project has not begun construction by 

this time, a new [applicability] analysis and determination will be required." See PSD Applicability 

Analysis for the Carlsbad Energy Center Project at 2. In this case, the California Energy Commission did 

not issue the necessary approvals that would allow NRG to start construction by June 30, 2011, so NRG 

did not have authority to begin actual construction on the CECP by that date. 

Accordingly, the prior applicability determination is no longer valid. In withdrawing this PSD 

applicability determination as moot, we also note that we have concluded that the analysis contained in it 

was made in error. As such, neither the overall determination nor the rationale and analysis contained 

therein can be relied upon to undertake actions related to the CECP or any other facility. In revoking this 

particular analysis, EPA emphasizes that there still may be specific permitting circumstances in which 

EPA may use the discretion provided by 40 CFR §52.21 (b)(48)(i) to select a different period for 

determining the baseline actual emissions, but the use of such discretion will be based on the particular 

facts of the permitting situation under consideration. I 

I EPA also notes that the discretion to consider a different period for calculating baseline actual 

emissions for determining PSD applicability is limited to applicability determinations performed by the 

Agency and other approved permitting authorities and may not be invoked independently by emission 

sources and/or permit applicants. See 40 CFR §52.21 (b)(48)(i) (limiting use of a different time period 

to the Administrator's determination "that it is more representative of normal source operation"); 40 

CFR §51.166 (b)(48)(i) (providing same discretion to approved permitting authorities). 
EPA is committed to working with NRG to complete a new applicability determination for the CECP. If 

such a determination is requested, please be aware that EPA will also consider PSD applicability for 

greenhouse gases that might be emitted from the project. See 40 CFR §52.21 (b)(48)(v)(b); 75 Fed. Reg. 

31514,31527 (June 3, 2010). If you have any questions, please contact Shaheerah Kelly of the Air 

Permits Office at (415) 947-4156. 

Sincerely, 

Deborah Jordan 

Director, Air Division 

cc:	 Robert Kard, San Diego Air Pollution Control District 

Steven Moore, San Diego Air Pollution Control District 

Tom Andrews, Sierra Research 

Mike Monasmith, California Energy Commission 

Will Walters, Aspen Environmental Group 

Joe Garuba, City of Carlsbad