### SO2 NOx PM Fine PM Coarse SO2 NOx PM 98th Percentile Impact (dv)3 

### 98th Percentile

Improvement (dv) Class I

Area Meterological

Year Modeling preformed by Minnkota1,4 

### Precontrol 7231.2 2855.2 5.5 36.7 No control No control Existing ESP 3.770 NATRNP-SU 2002 Run 1 7231.2 1070.7 5.5 36.7 No control ASOFA+SNCR Existing ESP 2.766 1.004TRNP-SU 2002 Run 2A 723.1 2855.2 5.5 36.7 FGD at 90% No control Existing ESP 1.768 2.002 TRNP-SU 2002 Run 2B 361.6 2855.2 5.5 36.7 FGD at 95% No control Existing ESP 1.694 2.076TRNP-SU 2002 Run 3A 7231.2 2855.2 5.8 38.5 No control No control CD Rate w/ dry FGD 3.552 0.218TRNP-SU 2002 Run 3B 7231.2 2855.2 11.6 77.1 No control No control CD Rate w/ wet FGD 3.568 0.202 TRNP-SU 2002 Run 4 723.1 1070.7 11.6 77.1 FGD at 90% ASOFA+SNCR CD Rate w/ wet FGD 0.847 2.923 TRNP-SU 2002 Modeling preformed by ND Dept. of Health2,5 

### ND Run 1 361.6 288.5 11.6 77.1 FGD at 95% ASOFA+SCR CD Rate w/ wet FGD 0.294 3.476TRNP-SU 2002 1

### See Appendix C.4 of SIP 2

### See Appendix B.4 of SIP

4

### The precontrol NOx emission rate reflects actual operation from the highest emitting day of the years 2000-2002 (meteorological period modeled per the NDDH BART protocol) and a heat input rate of 3180 MMBtu/hr. By contrast, the control scenario NOx emission rates assume operation at a more representative heat input rate of 2955 MMBtu/hr. For SO2, the assumed percent reduction from the given control technology was appliled to the precontrol emission rate. 5

### For NOx, NDDH applied the assumed percent reduction for the given control scenario to the precontrol emission rate. Scenario

3

### Visibility impacts are influenced by new, taller stack for all control scenario runs. **Milton R. Young Unit 1 CALPUFF Modeling** Emission Rate (lbs/hr) Control Option

9/20/2011SO2 NOx PM Fine PM Coarse SO2 NOx PM 98th Percentile Impact (dv) 98th Percentile

Improvement (dv) Class I

Area Meterological

Year Modeling preformed by Minnkota1,3 Precontrol 6879.0 5364.2 28.1 178.7 Existing Wet Scrubber No control Existing ESP/Wet Scrubber 4.503 NATRNP-SU 2002 Run 1 6879.0 2011.6 28.1 178.7 Existing Wet Scrubber ASOFA+SNCR Existing ESP/Wet Scrubber 3.008 1.495 TRNP-SU 2002 Run 2A 1574.4 5364.2 28.1 178.7 FGD at 90% No control Existing ESP/Wet Scrubber 3.08 1.423 TRNP-SU 2002 Run 2B 773.7 5364.2 28.1 178.7 FGD at 95% No control Existing ESP/Wet Scrubber 2.876 1.627TRNP-SU 2002 Run 3 6879.0 5364.2 21.0 133.7 Existing Wet Scrubber No control CD Rate 4.338 0.165 TRNP-SU 2002 Run 4 1574.4 2011.6 21.0 133.7 FGD at 90% ASOFA+SNCR CD Rate 1.612 2.891 TRNP-SU 2002 Modeling preformed by ND Dept. of Health2,4 ND Run 1 773.7 2011.6 21.0 133.7 FGD at 95% ASOFA+SNCR CD Rate 1.124 3.379 TRNP-SU 2002 ND Run 2 773.7 536.4 21.0 133.7 FGD at 95% ASOFA+SCR CD Rate 0.558 3.945 TRNP-SU 2002 1See Appendix C.4 of SIP 2See Appendix B.4 of SIP 3The precontrol NOx emission rate reflects actual operation from the highest emitting day of the years 2000-2002 (meteorological period modeled per the NDDH BART protocol) and a heat input rate of 5991 MMBtu/hr. By contrast, the control scenario NOx emission rates assume operation at a more representative heat input rate of 5158 MMBtu/hr. For SO2, the assumed percent reduction from the given control technology was appliled to the precontrol emission rate. 4For NOx, NDDH applied the assumed percent reduction for the given control scenario to the precontrol emission rate. Control Option **Milton R. Young Unit 2 CALPUFF Modeling**

Scenario Emission Rate (lbs/hr)

7/14/2011