March 11, 2011

In Reply

Refer To:

AIR-3

SAC 06-01

Steve Royall

Senior Plant Manager

Colusa Generating Station

4780 Dirks Road

Maxwell, California 95955

Re: Administrative Amendment to Prevention of Significant Deterioration Permit for

Colusa Generating Station, PSD Permit No. SAC 06·01

Dear Mr. Royall:

This letter is in response to your request dated January 7, 2011 for technical corrections

to the Prevention of Significant Deterioration (PSD) permit issued to the Pacific Gas and Electric

Company (PG&E) on September 29,2008, as amended on March 19,2010, for the construction

and operation of the Colusa Generating Station (CGS) in Colusa County, California. You state

that several short-term emissions limits for "startup" periods in the PSD permit were incorrectly

transposed and request that these emission limits be relocated to appropriately reflect facility

operations during different startup periods. For the reasons discussed below, I am approving

these corrections as administrative amendments to the PSD permit.

Specifically, you state that several of the pound per hour (lb/hour) emission limits in the

PSD permit for nitrogen oxides (NOx) and carbon monoxide (CO) emissions during "startup"

periods, as provided in the table in Condition X.E.5 of the permit, were placed incorrectly and

should be relocated to appropriately reflect facility operations during "cold startup," "warm

startup," and "hot startup" periods. I Condition X.E.5 establishes, among other things, the

following emission limits during "startup" periods: (1) for NOx, 333.3 lb/hour during cold

startup, 152.0 lb/hour during warm startup, and 249.90 lb/hour during hot startup; and (2) for

CO, 373.61b/hour during cold startup, 370.3 lb/hour during warm startup, and 429.61b/hour

during hot startup. You state that typical permit conditions for this type of facility provide for

the highest emissions during a "cold startup," followed by lower emissions during a "warm

startup" and the lowest emissions during a "hot startup." Accordingly, you request that we

reverse the NOx limits for "warm" and "hot" startup (resulting in 249.90 lb/hour during warm

I Condition X.E. 9 of the PSD permit defines "startup" as the period beginning with ignition and

lasting until the equipment has reached a continuous operating level and meets the permit limits

specified in Condition X.D.3. of the permit. Condition X.E.9 also defines "cold startup," "warm

startup," and "hot startup."
startup and 152.0 lb/hour during hot startup), and that we transpose all three CO limits (resulting

in 429.61b/hour during cold startup, 373.61blhour during warm startup, and 370.3 Ib/hour during

hot startup).

We agree that a facility ofthis type generally requires the highest ofstartup emissions

during a cold startup, followed by lower emissions during a warm startup and the lowest

emissions during a hot startup. We also agree with your conclusion that the startup emissions

limits for CGS in Condition X.E.5 ofthe PSD permit appear to have been incorrectly transposed

and that technical corrections are appropriate to reflect CGS's operations during these different

startup events. These corrections to the PSD permit for CGS do not alter our prior BACT or

ambient air quality impacts analyses and will not result in more than de minimis emissions

Increases.

For these reasons, we are processing the corrections you have requested as administrative

amendments to the PSD permit for CGS, effective immediately. In addition, we are updating the

facility's address on the PSD permit. We have attached the amended permit. If you have any

questions, please contact Shaheerah Kelly of our Permits Office at (415) 947-4156 or

kellv .shaheerahupepa.gov.

Sincerely,

Deborah Jordan

Director, Air Division

Enclosure: Amended PSD Permit

cc: Jon Maring, Pacific Gas and Electric Company, Roseville, CA

Harry Krug, Colusa County Air Pollution Control District

T. J. Gomez, Colusa County Air Pollution Control District

Robert Fletcher, California Air Resources Board

Dale Rundquist, California Energy Commission

Chris Davis, California Energy Commission

Jerry Salamy, CH2M Hill