Calculating 2017 NOX Emissions

March 25, 2015

To calculate the 2017 Base Case emissions and produce a flat file for air quality modeling, EPA started with the 2018 Base Case results and 

made modifications to emissions of units in three categories.

1) SCR Operation/Installation: For units that had an SCR in 2018 but were assumed to not operate (or be installed) in 2017, EPA 

recalculated the NOX emissions for the unit with the 2018 heat input and the 2016 emissions rate. 

2) Retirements: For units projected to retire in 2018, emissions from the 2016 run year were included in the 2017 emissions. 

3) Coal-To-Gas: For units that had implemented coal-to-gas retrofit options in 2018 and had not dispatched, emissions from the 

2016 run year were incorporated. However, if the coal-to-gas retrofit options had dispatched in 2018, then the NOX emissions 

were calculated based on the 2018 fuel use and 2016 NOX rate.

The table below lists the units that were affected by these changes and the number of tons added to the 2018 Base Case results to 

calculate the 2017 Base Case NOX emissions. 

NEEDS 

UNIQUE ID

Reason For 

Emissions Change

2018 Ozone 

Season NOX

(tons)

2018 

Annual NOX

(tons)

Incremental 

Ozone Season 

NOX (tons)

Incremental 

Annual NOX

(tons)

2017 Ozone 

Season NOX

(tons)

2017 Annual 

NOX (tons)

667_B_1 Coal-To-Gas 0.26 0.26 165.70 378.02 165.96 378.28

667_B_2 Coal-To-Gas 0.30 0.30 194.93 444.71 195.23 445.01

469_B_4 Coal-To-Gas 0.00 0.00 1,665.81 4,132.61 1,665.81 4,132.61

10676_B_5 Retirement 56.67 131.53 185.27 430.00 241.95 561.53

1077_G_3 Retirement 0.00 0.00 24.29 30.71 24.29 30.71

1378_B_1 Retirement 0.00 0.00 1,256.61 2,857.72 1,256.61 2,857.72

1378_B_2 Retirement 0.00 0.00 1,163.07 2,644.98 1,163.07 2,644.98

1378_B_3 Retirement 0.00 0.00 5,389.64 8,864.66 5,389.64 8,864.66

1394_B_1 Retirement 0.00 0.00 2.84 21.88 2.84 21.88

1394_B_2 Retirement 0.00 0.00 3.90 29.99 3.90 29.99

1394_B_5 Retirement 0.00 0.00 10.33 79.54 10.33 79.54
NEEDS 

UNIQUE ID

Reason For 

Emissions Change

2018 Ozone 

Season NOX

(tons)

2018 

Annual NOX

(tons)

Incremental 

Ozone Season 

NOX (tons)

Incremental 

Annual NOX

(tons)

2017 Ozone 

Season NOX

(tons)

2017 Annual 

NOX (tons)

1507_B_1 Retirement 0.00 0.00 4.21 12.69 4.21 12.69

1507_B_2 Retirement 0.00 0.00 3.42 11.59 3.42 11.59

1507_B_3 Retirement 0.00 0.00 2.52 10.69 2.52 10.69

1507_B_4 Retirement 0.00 0.00 22.43 51.25 22.43 51.25

1571_B_1 Retirement 0.00 0.00 709.98 1,628.36 709.98 1,628.36

1619_B_3 Retirement 0.00 0.00 0.07 0.15 0.07 0.15

1619_B_4 Retirement 0.00 0.00 8.33 8.33 8.33 8.33

170_B_4 Retirement 0.00 0.00 50.56 50.56 50.56 50.56

1769_B_7 Retirement 0.00 0.00 618.14 1,434.63 618.14 1,434.63

1769_B_8 Retirement 0.00 0.00 604.21 1,402.30 604.21 1,402.30

1769_B_9 Retirement 0.00 0.00 613.45 1,423.73 613.45 1,423.73

2324_B_4 Retirement 0.00 0.00 974.51 2,223.23 974.51 2,223.23

271_B_5 Retirement 0.00 0.00 0.54 0.54 0.54 0.54

271_B_6 Retirement 0.00 0.00 0.67 0.67 0.67 0.67

477_B_5 Retirement 0.00 0.00 1,020.45 2,345.48 1,020.45 2,345.48

6181_B_1 Retirement 0.00 0.00 543.96 1,238.72 543.96 1,238.72

6181_B_2 Retirement 0.00 0.00 251.57 361.87 251.57 361.87

6183_B_SM-1 Retirement 0.00 0.00 331.86 331.86 331.86 331.86

160_B_3 SCR Retrofit 152.18 349.36 1,204.67 2,765.52 1,356.85 3,114.88

113_B_3 SCR Retrofit 223.79 510.54 918.09 2,094.52 1,141.88 2,605.06

160_B_2 SCR Retrofit 288.81 663.53 828.93 1,904.11 1,117.75 2,567.63

113_B_4 SCR Retrofit 316.87 726.74 1,344.23 3,083.01 1,661.09 3,809.75

113_B_2 SCR Retrofit 321.92 734.41 922.27 2,104.03 1,244.18 2,838.45

6101_B_BW91 SCR Retrofit 441.12 1,011.73 905.39 2,076.53 1,346.52 3,088.26

1893_B_4 SCR Retrofit 454.61 1,065.46 508.65 1,158.31 963.26 2,223.77
NEEDS 

UNIQUE ID

Reason For 

Emissions Change

2018 Ozone 

Season NOX

(tons)

2018 

Annual NOX

(tons)

Incremental 

Ozone Season 

NOX (tons)

Incremental 

Annual NOX

(tons)

2017 Ozone 

Season NOX

(tons)

2017 Annual 

NOX (tons)

6204_B_3 SCR Retrofit 639.85 1,457.06 1,389.82 3,164.91 2,029.66 4,621.97

6204_B_2 SCR Retrofit 643.74 1,465.94 1,061.66 2,417.61 1,705.40 3,883.55

6204_B_1 SCR Retrofit 645.69 1,470.38 1,084.65 2,469.97 1,730.34 3,940.35

2817_B_1 SCR Retrofit 759.49 1,732.68 240.04 547.62 999.53 2,280.30

6076_B_2 SCR Retrofit 796.92 1,827.76 935.01 2,144.47 1,731.94 3,972.23

6076_B_1 SCR Retrofit 806.57 1,849.89 960.67 2,203.32 1,767.25 4,053.21

6030_B_2 SCR Retrofit 899.48 2,300.39 461.47 685.55 1,360.95 2,985.94

2442_B_5 SCR Retrofit 1,201.55 2,732.50 4,849.76 11,029.08 6,051.32 13,761.58

2442_B_4 SCR Retrofit 1,207.72 2,746.53 4,734.40 10,766.73 5,942.12 13,513.26

6030_B_1 SCR Retrofit 1,109.01 2,857.26 592.74 863.94 1,701.75 3,721.20

2963_B_3313 SCR Retrofit 1,717.27 3,910.59 1,175.57 2,677.03 2,892.84 6,587.62