# MinnkotaPower
[!VIPQ 

## coo PER A T I V E, 

### INC.

1822 Mill Road· P.O. Box 13200 • Grand forks, NO 58208-3200 • Phone (701) 795-4000 November 12, 2009

Mr. Terry O'Clair Director, Division ofAir Quality North Dakota Department of Health 918 E. Divide Avenue, 2nd FI Bismarck, ND 58501-1947 YourTouchstoneEnergy· Parmer**""'~** 

# -

RE: NOx BestAvailable Control Technology Analysis Study

- Supplemental Reports for M.R. Young Station Units 1 and 2, dated November2009
Dear Mr. O'Clair:
In accordance with the July 27, 2006, new source review enforcement consent decree, Minnkota Power Cooperative, Inc. ("Minnkota") submitted a NOx BestAvailable Control TechnologyAnalysis Studyto the North Dakota Department of Health ("NDDH") on October4, 2006. Based on this submission, as supplemented by responses to various comments by NDDH and the U.S. Environmental Protection Agency ("EPA"), NDDH issued its preliminary BestAvailable Control Technology Determination ("BACT Determination") on February 27, 2008. The preliminary BACT Determination concluded that selective catalytic reduction ("SCR") technologies were technically infeasible at Minnkota's Milton R. Young Station ("MRYS") Unit 1 and Unit 2. Consequently, NDDH did not analyze SCR technology beyond Step 2 of EPA's Top-Down BACTAnalysis method. Subsequently, NDDH determined that low-dust and tail-end SCR technologies were technically feasible and in a letterdated July 15, requested that Minnkota submit an economic analysis and other information required by Steps 3 and 4 ofthe top down BACT analysis process for low dust and tail end SCR applications at Milton R. Young Station.
In response to this request, please find enclosed two reports entitled "NOx Best Available Control Technology Analysis Study

- Supplemental Reportfor M.R. Young Station Unit 1" and "NOx BestAvailable Control Technology Analysis StudySupplemental Report for M.R. Young Station Unit 2", both dated November2009. This analysis is supplemental to Minnkota's original October2006 BACTAnalysis as well as all other materials Minnkota has submitted in this proceeding.
The enclosed reports indicated both low dust and tail end SCRs are not economically acceptable on either Unit 1 or Unit 2. For Unit 1, the Unit Control Costs(UCCs) range from a low of $3,944/ton to a high of$6,597/ton forthe low dust ortail end options withAdvanced Separated Over Fire Air. These UCCs are approximately270 percentto 525 percent ofthe UCC for SNCR w/ASOFA. The incremental costs perton from SNCR w/ASOFA to a low dust ortail end SCR option range from a low of $7,058 to $15,550/ton. All ofthese cost parameters show low dust and tail end SCRs are not economicallyacceptable.
Underthe prevailing standard of review, People to Save the Sheyenne River, Inc. v. North Dakota Dept. ofHealth, 697 NW.2d 319 (N.D. 2005), NDDH's BACT Determination is entitled to significant deference, and may only be set aside if-based on the record before it-NDDH's decision was the product of an irrational mental process or ifa reviewing court can discern no rationale forthe decision. EPA submitted comments on the BACT Determination on July31 , 2008, expressing its disagreement with a numberoftechnical conclusions, chief among them that neitherSCR technology was technically feasible at MRYS. EPA suggested that NDDH complete the remainder ofthe Top-Down BACT Analysis process for SCA. NDDH requested that Minnkota prepare a supplementto its original October2006 BACTAnalysis and includethe balance ofthe Top-Down BACT Analysis approach for SCR technology. Minnkota is confidentthat underthe People to Save the Sheyenne Riverstandard, NDDH's February 2008 BACT Determination was based on a rational mental process supported by a rationale evident in the record. More specifically, Minnkota believes that its submissions and NDDH's original February2008 BACT Determination are correct: lowdust and tail-end SCRtechnologies are technically infeasible at MRYS Unit 1and Unit2, because of problems associated with catalystfouling and deactivation, primarilythrough concentrations ofalkali mineral compounds; This is bolstered bythe fact thatthe two catalyst vendors Minnkota worked with while doing the in depth cost analysis told us thattheywould not offerany catalyst life guarantees without extensive testing. This both supports the priorconclusions reached by Minnkota and the NDDH as to the potential of catalyst poisoning and that SCTtechnology is not currently "available" for application at either unit at Milton R. Young Station.
Minnkota believes thatthe total record, both technical and economic, supports afinding that Advanced Separated Over-fire Airwith Selective Non-catalytic Reduction constitutes BACTfor Milton RYoung Station Units 1 and 2. Should you have anyquestions concerning this submittal, please contact me at 701- 795-4221.
Sincerely,
MINN OTA POWER COOPERATIVE, INC.

# £~~ John T. Graves, P.E. Environmental Manager C: David Sogard Ron Rutherford, USEPA