January 26, 2010

Suzanne Stevens Senior EHS Specialist Colorado-Golden Energy Corp.

25 10 th Street, P.O. Box 4088 Golden, CO 80401

Subject: Questions/Review for Colorado Energy Na tions “NOx Technical Feasibility and Emission Control Costs Colorado Energy Nations Golde n, Colorado” Submittal (November 16, 2009)

Please review the following questions discussed in the Division/Colorado-Golden Energy Corp. Conference Call on January 26, 2010.

1. CEN will be required to install LNB w/ OF A for BART. Can you provide support that

ULNBs will not result in further NOx reductions for documentation purposes?

2. CEN explained thoroughly the basis for using the current coal supply. For a complete review of fuel-switching, CEN needs to also examine fuels besides coal. These types of fuels include natural gas, biomass, etc. Please provide a qualitative discussion of the feasibility of using these fuels and whether these types of fu els will result in NOx benefits. The Division conducted a cursory review of the most recent Operation Permit (96OPJE143) for Boilers 4 & 5 to determine if fuel-switching would ha ve beneficial NOx reductions from fuel switching to wood/biomass. Other facilities of similar size in Colorado have reviewed using other fuels, such as wood, fuel oil, biomass (e.g. biodiesel or other renewable fuels), and natural gas. There is currently a paucity of information regarding emission factors for

biodiesel and other biomass fuels from the Di vision’s broad literature review. However, there is available emission factors regardi ng wood fuels under EPA’s AP-42 emission factor

database at: http://www.epa.gov/ttn/chief/ap42/ch01/final/c01s06.pdf

An example operating permit to review for w ood-fired emission limits is Black Hills W.N. Clark Power Plant (95OPFR076) at: http://www.cdphe.state.co.us/ap/downop/fr076p06.pdfThe Division will use literature review and simila r facility data to determine the plausibility of using other fuels for these two boilers. A qualitative explanation regarding the feasibility of using natural gas, fuel oil, ethanol, sludge and/or wood as the primary fuel for Boilers 4 and 5 will aid in the Division’s documentation in the four-factor analysis for Colorado Energy Nation’s Golden facility.

3. CEN needs to conduct a brief review of the ot her three factors: non-air and energy impacts, time necessary for compliance, and useful life.

i. Currently, the analysis mentions urea and electricity use, but only from cost perspective. The Division has conduct ed a literature revi ew of non-air and energy impacts from SCR and SNCR and compiled an overall summary (Attachment 1). Please add any relevant information for your facility to this summary (see Note to Facilities at end).

ii. Used remaining useful life from EP A Cost Control Manual – 20 years.

iii. Time necessary quoted by other sources – 2015 for SNCR (2-3 years) and 2016 (3-4 years) for SCR (from EPA SIP approval) – does this seem

reasonable?

NOTE: Documentation that is provided by the so urce allows the Division to account for sourcespecific data and unique factors. Otherwise, the Division will be fo rced to rely on similar facility

information and a broad literature review.

Please contact Kirsten King, Roland Hea, Curt Taipale, or Lisa Clarke with any further questions or comments. Any additional information that Colorado Energy Nations can provide as soon as possible as facilitate the Division’s analysis.

Sincerely,

Lisa Clarke Air Pollution Control Division - Policy & Planning Program Colorado Department of Public Health and Environment (303) 692-3117

Lisa.Clarke@state.co.us