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ENVIRONMENTAL HEALTH SECTION 

~~ Gold Seal Center, 918 E. Divide Ave. NORTH DAKOTA Bismarck, ND 58501-1947 

~~ DEPARTMENT oj HEALTH 701.328.5200 (fax) 

www.ndhealth.gov 

August 3, 2010 

Mr. James Martin (8RA) 

Regional Administrator 

U.S. EPA, Region 8 

1595 Wynkoop Street 

Denver, CO 80202-1129 

Re: 	 Supplement No. 1 to the North Dakota 

State Implementation Plan for Regional Haze 

Dear Mr. Martin: 

Accompanying this letter is a letter from Governor Hoeven to Administrator Jackson formally 

submitting a supplement to the North Dakota State Regional Haze State Implementation Plan. 

The supplement includes a Reasonable Progress analysis for the R.M. Heskett Station Unit 2. 

Enclosed are two hardcopies and three electronic copies of the supplement. 

Also enclosed is a revised page 186 of the original Regional Haze State Implementation Plan 

which was submitted in March. Table 9.9 has been corrected to indicate the visibility 

improvement from the proposed changes at the Tioga Gas Plant would improve visibility 0.05 

deciviews at Lostwood Wilderness Area (not 0.5 as indicated in the original analysis). 

If you have any questions, please have your staff contact Tom Bachman of my staff at 

(701 )328-5188. 

;:;cJd 

Terry L. O'Clair, P.E. 

Director 

Division of Air Quality 

TLOITB:cse RECEIVED 

Ene: 

xc: Gail Fallon, EPA Region 8 

U.S. EPA Region 8 

M's Office 

Environmental Health Division of Division of Division of Division of 

Section Chiefs Office Air Quality Municipal Facilities Waste Management Water Quality 

701.328,5150 701.328.5188 701.328.5211 701.328.5166 701.328.5210 

Printed on recycled paper. 
future emissions inventory was modified to reflect the control technology for each candidate 

source (AVS 1 EGU, AVS 2 EGU, Coyote EGU, and Tioga Gas Plant), and modeling was 

conducted using the revised future inventory for one source at a time. The reasonable progress 

goals in 40 CFR 51.308(d)(1) requires improvement in the most impaired days. The most 

impaired days are defined in 40 CFR 51.301 as the average visibility impairment for the twenty 

percent days with the highest amount of visibility impairment. Therefore, modeling addressed 

the 20% worst days for both TRNP and L W A Class I areas. The results for each candidate 

source were compared with the results using the unmodified future emissions inventory (Table 

8.11) to determine the additional visibility improvement due to the tested control technology. 

Modeled visibility improvement, for each candidate source/technology, is provided in Table 9.9. 

The single source controlled emissions (modeled tons per year) and annualized cost effectiveness 

(dollars per deciview) are also reported in the table. Reported visibility improvement (in 

deciviews) reflects the higher value for either TRNP or L WA. Note that visibility improvement 

reported for Coyote represents the total for both S02 and NOx control technologies, and the 

improvement reported for the Tioga Gas Plant represents the total for all 1920 and 2350 

horsepower engines. As shown in the table, predicted visibility improvement is very marginal 

for all candidate sources/technologies, and consequently cost per deciview is very high. 

Table 9.9 


Visibility Improvement and Cost Effectiveness 


I Visibility Visibility : Improvement Improvement Cost i Control Emissions I (dv)* (% *** Effectiveness 

I Source Pollutant Technology (TPY) TRNP LWA TRNP LWA ($/dv)** 

AVSI NO. LNB+SNCR 2,358 0.005 0.01 0.03 0.05 1,124,000,000 

AVS2 NO. LNB+SNCR 2,144 0.005 0.01 0.03 0.05 1,124,000,000 

Coyote S02 Wet Scrubber 1,924 0.02 0.04 0.11 0.20 1,113,000,000 

NO. ASOFA+SNCR 5,871 

TiogaG.P. 

1920 BHp Engines NO. LEC Retrofit 268 0 0.05 0 0.26 I 21,200,000 

2350 BHp Engines NO. SCR 33 I 

*The less efficient technologies evaluated would provide less improvement. 


**Based on the maximum visibility improvement (per source) at any Class I area in North 


Dakota. 


***Improvement (%) from baseline conditions. 


Time Necessary for Compliance 

Up to 6.5 years after SIP approval is necessary to achieve compliance (see EC/R report in 

Appendix 1.1). Additional time may be necessary if normal maintenance outages do not coincide 

with the projected schedule. It is anticipated that all required changes could be implemented by 

2018 depending on the date of approval of this SIP. It is not anticipated that any of the 

remaining sources will be retired prior to 2018. 

186