~~/g~~-DAKOTA ADivision of MDU Resources Group, Inc.

400 North Fourth Street

Bismarck, ND 58501

(701) 222·7900

June 14,2011

u.s. Environmental Protection Agency Region VIII

1595 Wynkoop Street

Denver, CO 80202-1 129

Attention: Vanessa Hinkle, 8P-AR

Re: Updated Response to Request for Additional Reasonable Progress Information for

tbe Montana-Dakota Utilities Company, Lewis and Clark Generating Station,

Pursuant to Section 114(a) of the Clean Air Act (42 U.S.c. Section 7414(a»

Dear Ms. Hinkle:

Montana-Dakota Utilities Co. respectfully submits the enclosed emission control analysis for

Lewis & Clark Generating Station's Unit I in response to the EPA request issued on November 5,

2010 as an update to the analysis previously submitted on February II, 20 I I. The analysis has

been updated to revise prior reported costs associated with the NOx control costs and the

hydrated lime use costs for SO, control based on additional information which became available

after the initial due date for the analysis. The report is being supplied in its entirety and serves to

replace the previously filed February 2011 version of the report.

For ease in identifying the changes to the report, the tables of interest (Table 2 and Table 5 ofthe

analysis) have been reproduced below to illustrate, in red, the values that have been updated.

While the costs increased on an absolute basis, none ofthe conclusions on the comparative cost

basis have changed since the February submittal.

Table Z. SO, Control Cost Summary

Installed Annualized Pollution Incremental

Capital Cost Operating Cost Control Cost Control Cost

Control Technology (MM$) (MM$/yr)* ($Iton)** ($Iton)***

SDA with Baghouse $66.34 $10.05 $11,825 $13,220

Existing Scrubber Mod. $0.27 $0.14 $1,383 NA

DSI with Baghouse $15.75 $2.84 $28,347 NA

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•••

Pnor reported: SDA with Baghousc, $9.68: EXlstmg Scrubber Mod., SO. 10: OSl wuh Baghollse S2.80.

Prior reported: SDA with Baghouse, $11,390: Existing Scrubber Mod., $1.015; OSI with Baghouse 527,912.

Prior reported (Slton): SDA with Baghollse. S12,776.
Vanessa Hinkle

June 8,2011

Page 2

Table 5. NOx Control Cost Summary

PrIor reported. SNCR wuh SOFAlLNB, S>.69, SOFAlLNB, 51.».

Prior reported: SNCR with SOFAlLNB, $0.96; SOFAlLNB, SO.23.

Prior reported: SNCR with SOFAlLNB, $2,395; SOFAlLNB, $1,213 .

Prior reported: SCR, $ 18,786

•

..

...

.....

Installed Annualized Pollution Incremental

Capital Cost Operating Cost Control Cost Control Cost

Control Technology (MMS)* (MMS/yr)** (S/ton)*** (S/ton)·***

SCR $38.98 $6.98 $9,680 $18,368

SNCR with SOFAlLNB $4.53 $1.09 $2,729 $7,279

SOFAlLNB $2.20 $0.36 $1,213 NA

SNCR $2.43 $0.76 $2,533 NA

SNCR (low load) $2.43 $0.56 $9,817 NA " " -

A statement of cenification for the enclosed analysis is provided with this cover letter. No claim

of confidential business information is being assened for the enclosed repon. In addition to the

electronic submittal, two (2) paper copies ofthis correspondence and the analysis have been

mailed to your attention. If you have any questions about this submittal, please contact Jon

Madison at 701-222-7835.

Sincerely,

Ms.

Ct/~~ Abbie Krebsbach

Environmental Manager

Montana-Dakota Utilities Co.

Enclosure: Updated Emissions Control Analysis for Lewis and Clark Station Unit I

cc: Mr. Joel Trinkle, Barr Engineering Company
Vanessa Hinkle

June 8, 2011

Page 3

STATEMENT OF CERTIFICATION

I certify under penalty oflaw that I have personally examined and am familiar with the

information submitted in this document and all attachments and that, based on my inquiry of

those individuals immediately responsible for obtaining information, I believe that the

information is true, accurate, and complete. I am aware that there are significant penalties for

submitting false information, including the possibility offine or imprisonment.

Signature

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