0.040
                                                                          0.022
                                                                         -0.038
                                                                         -0.112
                                                                         -0.040
Tribal Data
                                                                          0.084
                                                                          0.084
                                                                          0.084
                                                                          0.084
                                                                          0.084
                                                                          0.084
                                                                         -0.007
                                                                         -0.184
                                                                          0.001

Table D-11.  2023 Ozone Season Anthropogenic NOX Emissions Reductions (Tons) for non-EGUs and Fractional Difference in Emissions for the non-EGU Scenario Relative to the 2023 Air Quality Modeling Base Case for Each State.
                                     State
Non-EGU glass and cement, refined analysis, others unchanged, below $2,000/ton (Tons)
Fractional Difference EGU $1,800/ton +non-EGU tranche 1 glass & cement analyzed
Alabama
                                                                           -
                                                                          0.035
Arizona
                                                                           -
                                                                         -0.009
Arkansas
                                                                           -
                                                                         -0.018
California
                                                                           -
                                                                          0.005
Colorado
                                                                           -
                                                                         -0.009
Connecticut
                                                                           -
                                                                         -0.021
Delaware
                                                                           -
                                                                         -0.006
District of Columbia
                                                                           -
                                                                         -0.001
Florida
                                                                           -
                                                                          0.028
Georgia
                                                                           -
                                                                          0.016
Idaho
                                                                           -
                                                                          0.022
Illinois
                                                                           464
                                                                         -0.027
Indiana
                                                                           666
                                                                         -0.063
Iowa
                                                                           -
                                                                         -0.086
Kansas
                                                                           -
                                                                         -0.046
Kentucky
                                                                           -
                                                                          0.111
Louisiana
                                                                           -
                                                                          0.085
Maine
                                                                           -
                                                                          0.048
Maryland
                                                                           -
                                                                         -0.023
Massachusetts
                                                                           -
                                                                          0.004
Michigan
                                                                           -
                                                                         -0.029
Minnesota
                                                                           -
                                                                         -0.036
Mississippi
                                                                           -
                                                                          0.182
Missouri
                                                                           -
                                                                         -0.050
Montana
                                                                           -
                                                                          0.005
Nebraska
                                                                           -
                                                                         -0.028
Nevada
                                                                           -
                                                                          0.000
New Hampshire
                                                                           -
                                                                          0.049
New Jersey
                                                                           -
                                                                         -0.007
New Mexico
                                                                           -
                                                                         -0.048
New York
                                                                           238
                                                                         -0.025
North Carolina
                                                                           -
                                                                         -0.067
North Dakota
                                                                           -
                                                                         -0.060
Ohio
                                                                           -
                                                                         -0.076
Oklahoma
                                                                           -
                                                                         -0.003
Oregon
                                                                           -
                                                                          0.012
Pennsylvania
                                                                           -
                                                                         -0.023
Rhode Island
                                                                           -
                                                                         -0.019
South Carolina
                                                                           -
                                                                         -0.041
South Dakota
                                                                           -
                                                                          0.010
Tennessee
                                                                           -
                                                                          0.019
Texas
                                                                           -
                                                                          0.002
Utah
                                                                           -
                                                                         -0.039
Vermont
                                                                           -
                                                                          0.010
Virginia
                                                                           138
                                                                          0.040
Washington
                                                                           -
                                                                          0.042
West Virginia
                                                                           -
                                                                         -0.082
Wisconsin
                                                                           -
                                                                          0.002
Wyoming
                                                                           -
                                                                          0.045
Tribal Data
                                                                           -
                                                                          0.081

3. Description of the analytic results.

      For each year 2021-2025, EPA used the ozone AQAT to estimate improvements in downwind air quality at base case levels, at $1,800 per ton emission budget levels, and at higher dollar per ton emission budget levels.  At each cost threshold level, using AQAT, EPA examined the average and maximum design values for each of the receptors. EPA evaluated the degree of change in ppb and whether it decreased average or maximum values to below 76 ppb (at which point their nonattainment and maintenance issues, respectively, would be considered resolved).  EPA also examined each state's air quality contributions at each emission budget level, assessing whether a state maintained at least one linkage (i.e., greater than or equal to 1% (.75 ppb) to a receptor that was estimated to remain in nonattainment and/or maintenance.  EPA examined the engineering base case, $1,600/ton, $1,800/ton, $5,800/ton, and $9,600/ton.  EPA also created "straight line" estimates comparable to those used at Steps 1 and 2.  The preamble explains at section VI.D how EPA considered the results of the air quality analyses described in this TSD to determine the appropriate emission levels for eliminating significant contribution to nonattainment and interference with maintenance.
      For each year, the average and maximum design values (in ppb) estimated using the assessment tool for each identified receptor for each cost threshold level have been rounded to hundredths of a ppb and can be found in Tables D-12 through D-21.  There are four monitors, three in Connecticut and one in Texas.  Scenarios that are not viable, for technical or policy reasons, have been grayed out in these tables.
      In 2021, we observe that the Stratford monitor 090013007 in Fairfield County, Connecticut, switches to maintenance at the $1,600/ton level (where SCRs are optimized).  In other words, its average design value drops below 76 ppb (Table D-12), while its maximum design value stays above 76 ppb (Table D-13).  The Madison monitor 090099002 in New Haven County, Connecticut, has both its average and maximum design values below 76 at all cost levels, including in the Engineering Base.  It was estimated to have a maintenance issue in the 2021 Base Case interpolated from the air quality modeling and used at Steps 1 and 2 (with its maximum design value higher than 76 ppb).
      In 2024, there is only one receptor remaining (the Westport monitor 090019003 in Fairfield County, Connecticut).  This receptor switches from nonattainment to maintenance at $1,600/ton (Tables D-18 and D-19).
      EPA also assessed changes in air quality for the non-EGU scenarios for 2023, 2024, and 2025.  In these cases, we included EGU emission reductions at the $1,800/ton cost threshold level.  The results are shown in Table D-22.
      In the assessment of air quality using the calibrated assessment tool, we are able to estimate the change in the air quality contributions of each upwind state to each receptor (see the description of the state and receptor-specific contributions in section D.2.c.(2)) in order to determine whether any state's contribution is below the 1 percent threshold used in step 2 of the 4-Step Good Neighbor Framework to identify "linked" upwind states.  For this over-control assessment, we compared each state's adjusted ozone concentration against the 1% air quality threshold at each of the cost threshold levels up to $9,600/ton at each remaining receptor, using AQAT.  To see static air quality contributions and design value estimates for the four receptors of interest for each of the years for each of the cost levels, see the individual worksheets labeled: $9600; $5800; $3900; $1600 w CC & non-EGU; $1600 w CC; $1600 wo CC; $500; straightline_base; and eng_base. For interactive worksheets, refer to the "scenario_202X" worksheets after setting the desired scenario in the "summaryDVs" worksheet.  Then, adjust cells J27 and J28 to match the desired scenario of interest.  The numbering for the various scenarios is shown in Table D-23.  For a cost threshold run, cell J27 would be a value of 1 through 8, while cell J28 should be fixed with a value of 1.  For all linked states, in the cost threshold analysis, we did not see any instances where a state's contributions dropped below 1% of the NAAQS for all its linkages to remaining downwind receptors.  That is, if a state was linked to a receptor in 2021 in the base case, and that receptor remained either nonattainment or maintenance in other years or at other cost thresholds, the state remained linked with a contribution greater than or equal to 1% of the NAAQS. This is not a surprising result because, for a linkage to be resolved by emission reductions of just a few percent, the original base contribution would need to be within a few percent of the threshold.  As a hypothetical example, if the state is making a 6% emission reduction in its overall anthropogenic ozone season NOX emissions, and the calibration factor was 0.5, its original base case maximum contribution to a remaining unresolved nonattainment and/or maintenance receptor would need to be just under 1.03% of the NAAQS or 0.77 ppb, to drop below the 0.75 ppb linkage threshold.
       Lastly, once the EGU budgets for the rule were established (based on the results of the multi-factor test), it was possible to estimate air quality concentrations in the "control scenario" at each downwind receptor for each year using the ozone AQAT (Table D-24).  Here, we apply a scenario where all states (regardless of whether they are linked to a particular receptor or to a different receptor in the geography) have the same cost threshold applied as do the "linked" states.  We observe very little effect of this on air quality at the receptor and in no case are the changes large enough to shift the status of a receptor from either nonattainment to maintenance or from maintenance to attainment.  This is not surprising because the contributions to each receptor from these non-linked states are already below the 1% threshold.

Table D-12. 2021 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          76.50
                                                                          76.13
                                                                          76.11
                                                                          75.95
                                                                          75.93
                                                                          75.94
                                                                          75.93
                                                                          75.89
                                                                          75.83
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          78.56
                                                                          78.27
                                                                          78.26
                                                                          78.13
                                                                          78.12
                                                                          78.13
                                                                          78.12
                                                                          78.08
                                                                          78.03
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          73.98
                                                                          73.59
                                                                          73.57
                                                                          73.40
                                                                          73.38
                                                                          73.39
                                                                          73.37
                                                                          73.32
                                                                          73.25
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          75.51
                                                                          75.62
                                                                          75.58
                                                                          75.51
                                                                          75.51
                                                                          75.50
                                                                          75.50
                                                                          75.25
                                                                          74.95
Note: Scenarios that are not viable, for technical or policy reasons, have been grayed out

Table D-13. 2021 Maximum Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Maximum Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           75.2
                                                                          77.43
                                                                          77.05
                                                                          77.03
                                                                          76.87
                                                                          76.85
                                                                          76.86
                                                                          76.85
                                                                          76.81
                                                                          76.75
                                                                       90019003
CT
Fairfield
                                                                           77.2
                                                                          78.86
                                                                          78.58
                                                                          78.57
                                                                          78.44
                                                                          78.43
                                                                          78.43
                                                                          78.42
                                                                          78.39
                                                                          78.34
                                                                       90099002
CT
New Haven
                                                                           73.8
                                                                          76.15
                                                                          75.74
                                                                          75.72
                                                                          75.54
                                                                          75.53
                                                                          75.54
                                                                          75.52
                                                                          75.47
                                                                          75.39
                                                                      482010024
TX
Harris
                                                                           75.6
                                                                          77.15
                                                                          77.25
                                                                          77.21
                                                                          77.15
                                                                          77.15
                                                                          77.13
                                                                          77.13
                                                                          76.88
                                                                          76.57

Table D-14. 2022 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          75.40
                                                                          75.16
                                                                          75.14
                                                                          74.98
                                                                          74.97
                                                                          74.97
                                                                          74.96
                                                                          74.92
                                                                          74.87
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          77.73
                                                                          77.55
                                                                          77.54
                                                                          77.41
                                                                          77.39
                                                                          77.40
                                                                          77.39
                                                                          77.36
                                                                          77.31
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          72.84
                                                                          72.58
                                                                          72.56
                                                                          72.39
                                                                          72.37
                                                                          72.38
                                                                          72.37
                                                                          72.32
                                                                          72.25
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          74.76
                                                                          74.98
                                                                          74.94
                                                                          74.88
                                                                          74.88
                                                                          74.87
                                                                          74.87
                                                                          74.61
                                                                          74.32

Table D-15. 2022 Maximum Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Maximum Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           75.2
                                                                          76.31
                                                                          76.07
                                                                          76.05
                                                                          75.89
                                                                          75.87
                                                                          75.88
                                                                          75.87
                                                                          75.83
                                                                          75.77
                                                                       90019003
CT
Fairfield
                                                                           77.2
                                                                          78.03
                                                                          77.85
                                                                          77.84
                                                                          77.71
                                                                          77.70
                                                                          77.70
                                                                          77.69
                                                                          77.66
                                                                          77.61
                                                                       90099002
CT
New Haven
                                                                           73.8
                                                                          74.98
                                                                          74.71
                                                                          74.69
                                                                          74.51
                                                                          74.49
                                                                          74.50
                                                                          74.49
                                                                          74.44
                                                                          74.36
                                                                      482010024
TX
Harris
                                                                           75.6
                                                                          76.37
                                                                          76.60
                                                                          76.56
                                                                          76.50
                                                                          76.50
                                                                          76.48
                                                                          76.48
                                                                          76.23
                                                                          75.92

Table D-16. 2023 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          74.30
                                                                          74.13
                                                                          74.11
                                                                          73.88
                                                                          73.86
                                                                          73.87
                                                                          73.86
                                                                          73.80
                                                                          73.72
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          76.90
                                                                          76.74
                                                                          76.72
                                                                          76.48
                                                                          76.46
                                                                          76.48
                                                                          76.46
                                                                          76.39
                                                                          76.31
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          71.70
                                                                          71.51
                                                                          71.48
                                                                          71.24
                                                                          71.21
                                                                          71.23
                                                                          71.21
                                                                          71.14
                                                                          71.03
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          74.00
                                                                          74.55
                                                                          74.49
                                                                          74.38
                                                                          74.38
                                                                          74.36
                                                                          74.36
                                                                          73.95
                                                                          73.46

Table D-17. 2023 Maximum Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Maximum Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           75.2
                                                                          75.20
                                                                          75.03
                                                                          75.01
                                                                          74.78
                                                                          74.76
                                                                          74.77
                                                                          74.75
                                                                          74.69
                                                                          74.61
                                                                       90019003
CT
Fairfield
                                                                           77.2
                                                                          77.20
                                                                          77.04
                                                                          77.02
                                                                          76.78
                                                                          76.76
                                                                          76.78
                                                                          76.76
                                                                          76.69
                                                                          76.60
                                                                       90099002
CT
New Haven
                                                                           73.8
                                                                          73.80
                                                                          73.60
                                                                          73.58
                                                                          73.32
                                                                          73.30
                                                                          73.32
                                                                          73.29
                                                                          73.22
                                                                          73.12
                                                                      482010024
TX
Harris
                                                                           75.6
                                                                          75.60
                                                                          76.17
                                                                          76.10
                                                                          75.99
                                                                          75.99
                                                                          75.97
                                                                          75.97
                                                                          75.55
                                                                          75.05

Table D-18. 2024 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          73.76
                                                                          73.58
                                                                          73.56
                                                                          73.33
                                                                          73.31
                                                                          73.32
                                                                          73.30
                                                                          73.25
                                                                          73.17
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          76.38
                                                                          76.20
                                                                          76.18
                                                                          75.94
                                                                          75.92
                                                                          75.94
                                                                          75.92
                                                                          75.86
                                                                          75.78
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          71.14
                                                                          70.93
                                                                          70.90
                                                                          70.66
                                                                          70.63
                                                                          70.65
                                                                          70.63
                                                                          70.56
                                                                          70.46
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          73.58
                                                                          74.05
                                                                          73.98
                                                                          73.88
                                                                          73.88
                                                                          73.86
                                                                          73.86
                                                                          73.47
                                                                          73.01

Table D-19. 2024 Maximum Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Maximum Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           75.2
                                                                          74.65
                                                                          74.47
                                                                          74.45
                                                                          74.22
                                                                          74.20
                                                                          74.21
                                                                          74.19
                                                                          74.14
                                                                          74.06
                                                                       90019003
CT
Fairfield
                                                                           77.2
                                                                          76.68
                                                                          76.50
                                                                          76.48
                                                                          76.24
                                                                          76.22
                                                                          76.23
                                                                          76.22
                                                                          76.15
                                                                          76.07
                                                                       90099002
CT
New Haven
                                                                           73.8
                                                                          73.22
                                                                          73.01
                                                                          72.98
                                                                          72.73
                                                                          72.70
                                                                          72.72
                                                                          72.70
                                                                          72.62
                                                                          72.53
                                                                      482010024
TX
Harris
                                                                           75.6
                                                                          75.17
                                                                          75.65
                                                                          75.58
                                                                          75.48
                                                                          75.48
                                                                          75.46
                                                                          75.46
                                                                          75.06
                                                                          74.59

Table D-20. 2025 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          73.22
                                                                          73.04
                                                                          73.02
                                                                          72.79
                                                                          72.77
                                                                          72.79
                                                                          72.77
                                                                          72.72
                                                                          72.64
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          75.86
                                                                          75.68
                                                                          75.66
                                                                          75.42
                                                                          75.41
                                                                          75.42
                                                                          75.40
                                                                          75.34
                                                                          75.26
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          70.58
                                                                          70.37
                                                                          70.35
                                                                          70.10
                                                                          70.08
                                                                          70.09
                                                                          70.07
                                                                          70.00
                                                                          69.91
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          73.16
                                                                          73.62
                                                                          73.55
                                                                          73.45
                                                                          73.45
                                                                          73.43
                                                                          73.43
                                                                          73.04
                                                                          72.59

Table D-21. 2025 Maximum Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Maximum Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           75.2
                                                                          74.11
                                                                          73.93
                                                                          73.91
                                                                          73.67
                                                                          73.66
                                                                          73.67
                                                                          73.65
                                                                          73.60
                                                                          73.52
                                                                       90019003
CT
Fairfield
                                                                           77.2
                                                                          76.16
                                                                          75.98
                                                                          75.96
                                                                          75.72
                                                                          75.70
                                                                          75.71
                                                                          75.70
                                                                          75.64
                                                                          75.56
                                                                       90099002
CT
New Haven
                                                                           73.8
                                                                          72.65
                                                                          72.43
                                                                          72.41
                                                                          72.15
                                                                          72.13
                                                                          72.14
                                                                          72.12
                                                                          72.05
                                                                          71.96
                                                                      482010024
TX
Harris
                                                                           75.6
                                                                          74.74
                                                                          75.21
                                                                          75.14
                                                                          75.04
                                                                          75.04
                                                                          75.02
                                                                          75.02
                                                                          74.62
                                                                          74.16

Table D-22. Average and Maximum Ozone DVs (ppb) for non-EGU NOX Emissions Level* for Each Year Assessed.
                         Monitor Identification Number
                                     State
                                    County
                       CAMx 2023 Base Case Avg DV (ppb)
                          Average Design Value (ppb)
                          Maximum Design Value (ppb)

                                     2023
                                     2024
                                     2025
                                     2023
                                     2024
                                     2025
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          73.83
                                                                          73.28
                                                                          72.74
                                                                          74.72
                                                                          74.16
                                                                          73.62
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          76.43
                                                                          75.89
                                                                          75.37
                                                                          76.73
                                                                          76.19
                                                                          75.67
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          71.17
                                                                          70.60
                                                                          70.04
                                                                          73.26
                                                                          72.66
                                                                          72.09
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          74.36
                                                                          73.86
                                                                          73.43
                                                                          75.97
                                                                          75.46
                                                                          75.02
*non-EGU AQAT air quality estimates include EGU emission reductions at the $1,600/ton level.

Table D-23. Description of the Various Scenarios Modeled in AQAT.
                                   Scenario
                             Cost Threshold Level
                               Short Description
                                  Description
                                       1
                                      $0
                                   Eng base
Baseline 202x OS NOx + engineering nonCEMs
                                       2
                                     $500
                                     $500
Baseline 202x OS NOx + engineering nonCEMs + $500/ton Generation Shifting
                                       3
                                    $1,600
                                $1,600 w/o LNB
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + $1,600/ton Generation Shifting
                                       4
                                    $1,600
                                 $1,600 w LNB
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + LNB + $1,600/ton Generation Shifting
                                       5
                                    $1,800
                                $1,800 w/o LNB
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + SNCR Optimize + $1,600/ton Generation Shifting
                                       6
                                    $1,800
                                 $1,800 w LNB
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + LNB + SNCR Optimize + $1,600/ton Generation Shifting
                                       7
                                    $5,800
                                    $5,800
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + LNB + SNCR Optimize + SNCR Retrofit + $5,800/ton Generation Shifting
                                       8
                                    $9,600
                                    $9,600
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + LNB + SNCR Optimize + SCR Retrofit + $9,600/ton Generation Shifting
                                       9
                                      NA
                               Straightline base
202X Straight line emissions interpolation (an appoximation of that used for Steps 1 and 2).
                                      10
                                      NA

Analyzed...number of tons of non-EGU glass and cement, refined analysis.
                                      11
                              $1,800 up to $2,000
                          $1,800 w LNB & non-EGU
Baseline 202x OS NOx + engineering nonCEMs + 0.08 SCR Cap + LNB + SNCR Optimize + $1,600/ton Generation Shifting + non-EGU glass and cement, refined analysis, others unchanged, below $2,000 per ton.

Table D-24. Average and Maximum Ozone DVs (ppb) for the $1,800 Per Ton "Control Scenario" for each Year Assessed.
                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
                          Average Design Value (ppb)
                          Maximum Design Value (ppb)

                                     2021
                                     2022
                                     2023
                                     2024
                                     2025
                                     2021
                                     2022
                                     2023
                                     2024
                                     2025
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          75.94
                                                                          74.96
                                                                          73.85
                                                                          73.30
                                                                          72.77
                                                                          76.86
                                                                          75.87
                                                                          74.75
                                                                          74.19
                                                                          73.65
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          78.13
                                                                          77.39
                                                                          76.45
                                                                          75.92
                                                                          75.40
                                                                          78.43
                                                                          77.69
                                                                          76.75
                                                                          76.21
                                                                          75.69
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          73.39
                                                                          72.37
                                                                          71.20
                                                                          70.62
                                                                          70.07
                                                                          75.54
                                                                          74.48
                                                                          73.29
                                                                          72.69
                                                                          72.12
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          75.50
                                                                          74.86
                                                                          74.36
                                                                          73.86
                                                                          73.43
                                                                          77.13
                                                                          76.48
                                                                          75.97
                                                                          75.45
                                                                          75.02

4. Comparison between the air quality assessment tool estimates

      As described earlier, AQAT was calibrated using CAMx data from either 2016 or 2028.  Thus, it was possible to evaluate the estimates from the tool for a comparable scenario.  The average design values from AQAT for 2024 for the various scenarios are shown using the 2016-based calibration factor (Table D-25), as well as the differences between the values in Tables D-18 and D-25.  The differences are shown in Table D-26.  The AQAT values and the differences in the table have been rounded to a hundredth of a ppb.  For this set of scenarios, the differences are moderate, with a maximum value of 0.51 ppb.
      There can be a small offset between the estimates (based on the impacts of the two different calibration factors).  Within a set of estimates, the differences are likely to be comparable.  That is, comparing two different scenarios in Table D-18 with the same two scenarios in Table D-25, produces similar changes in air quality.  For example, the difference between the engineering base and the $1,800 per ton level where SCR and SNCR are optimized and combustion controls are installed results in a difference of 0.29 ppb when the 2028 calibration factor is applied and 0.19 ppb when the 2016 calibration factor is applied.  The results of this demonstrate that, considering the time and resource constraints faced by the EPA, the AQAT provides reasonable estimates of air quality concentrations for each receptor, can provide reasonable inputs for the multi-factor assessment, and can serve as a method to test for linkages dropping below the threshold.

Table D-25. 2024 Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors Using the Calibration Factor from the 2016 Modeling.

                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
CT
Fairfield
                                                                           74.3
                                                                          73.76
                                                                          73.79
                                                                          73.78
                                                                          73.61
                                                                          73.60
                                                                          73.61
                                                                          73.60
                                                                          73.56
                                                                          73.50
                                                                       90019003
CT
Fairfield
                                                                           76.9
                                                                          76.38
                                                                          76.52
                                                                          76.50
                                                                          76.38
                                                                          76.36
                                                                          76.37
                                                                          76.36
                                                                          76.33
                                                                          76.28
                                                                       90099002
CT
New Haven
                                                                           71.7
                                                                          71.14
                                                                          71.15
                                                                          71.14
                                                                          70.96
                                                                          70.95
                                                                          70.96
                                                                          70.94
                                                                          70.89
                                                                          70.82
                                                                      482010024
TX
Harris
                                                                           74.0
                                                                          73.58
                                                                          74.03
                                                                          73.99
                                                                          73.93
                                                                          73.93
                                                                          73.91
                                                                          73.91
                                                                          73.68
                                                                          73.40

Table D-26. 2024 Difference in Average Ozone DVs (ppb) for NOX Emissions Cost Threshold Levels ($/ton) Assessed Using the Ozone AQAT for All Receptors for the Estimates with the Two Different Calibration Factors.

                         Monitor Identification Number
                                     State
                                    County
                           CAMx 2023 Base Case (ppb)
              Assessment Tool Average Ozone Design Values (ppb).

                                 Straight line
                             Engineering Baseline
                                   $500/ton
                                 Optimize SCR
                              Optimize SCR + LNB
                              Optimize SNCR+ SCR
                           Optimize SNCR+ SCR + LNB
                      New SNCR + Optimize SNCR+ SCR + LNB
                      New SCR + Optimize SNCR+ SCR + LNB
                                                                       90013007
                                                                             CT
                                                                      Fairfield
                                                                           74.3
                                                                           0.16
                                                                           0.21
                                                                           0.22
                                                                           0.28
                                                                           0.29
                                                                           0.29
                                                                           0.29
                                                                           0.31
                                                                           0.33
                                                                       90019003
                                                                             CT
                                                                      Fairfield
                                                                           76.9
                                                                           0.23
                                                                           0.31
                                                                           0.32
                                                                           0.43
                                                                           0.44
                                                                           0.43
                                                                           0.44
                                                                           0.47
                                                                           0.51
                                                                       90099002
                                                                             CT
                                                                      New Haven
                                                                           71.7
                                                                           0.16
                                                                           0.23
                                                                           0.23
                                                                           0.30
                                                                           0.31
                                                                           0.31
                                                                           0.31
                                                                           0.33
                                                                           0.36
                                                                      482010024
                                                                             TX
                                                                         Harris
                                                                           74.0
                                                                           0.16
                                                                          -0.02
                                                                           0.01
                                                                           0.05
                                                                           0.05
                                                                           0.06
                                                                           0.06
                                                                           0.21
                                                                           0.38

E. Observations on Cost and Air Quality Factors in 2024

      Section VI of the preamble discusses the cost and air quality factors in the multifactor test and reaches the conclusions about the requisite level of emissions control for each year.  The higher mitigation technology scenarios associated with post-combustion control installation were not considered in the 2021 multi-factor test as they pertain to technologies not possible to install at a regional scale until 2025.  However, for illustrative purposes, EPA examined their reduction potential and air quality impact of these controls starting in 2024. As described in sections C and D of this TSD, EPA quantified emissions from upwind states at various levels of uniform NOX control stringency, each represented by uniform control technology and corresponding NOX reduction and then evaluated the potential air quality consequences of these potential reductions.
      EPA combines costs, EGU NOX reductions, corresponding improvements in downwind ozone concentrations, and other considerations for different control levels in its multi-factor test.  EPA examines whether any receptor shifts from nonattainment to maintenance or from maintenance to attainment.  In 2024, the last receptor (Westport) in Fairfield Connecticut shifts from nonattainment to maintenance at $1,600 per ton. This receptor is minimally above the 75.9 threshold in 2024 and is fully resolved by 2025.  No additional changes are observed at higher cost threshold levels in 2024 or 2025. EPA analysis of these more stringent scenarios in 2024 also results in a "knee-in-the-curve" graph (see preamble section VI for details about this figure for 2021).  Figure E-1 below illustrates the air quality improvement for the mitigation technologies up to $9,600 per ton for EGUs for 2024. In Figure E-1, the 2024 "knee" is also at a point where emission budgets reflect a control stringency with an estimated marginal cost of $1,600 and $1,800 per ton. The more stringent emission budget levels (e.g., emission budgets reflecting mitigation technologies that cost $5,800 per ton or greater) yield fewer additional emission reductions and fewer air quality improvements relative to the increase in control costs. These control measures also involve significant capital investment and the installation of new hardware at the EGU. For the reasons described in section VI of the preamble, the $1,800 per ton cost threshold is a reasonable stopping level for 2021 and 2022. Although EPA evaluated the potential reductions from post combustion controls, that technology did not qualify as an option for future years as EPA explains those controls are not possible on a regional scale until 2025, and EPA expects no remaining air quality problems for the 2008 ozone NAAQS standard in that year at the $1,800 per ton level.

      Figure E-1. EGU Ozone Season NOX Reduction Potential in 11 Linked States and Corresponding Total Reductions in Downwind Ozone Concentration at the Westport Fairfield Connecticut Receptor for each Cost Threshold Level Evaluated in 2024.

 Assessment of the Effects of Ozone on Forest Health

      Air pollution can impact the environment and affect ecological systems, leading to changes in the ecological community and influencing the diversity, health, and vigor of individual plant species. When ozone is present in the environment, it enters the plant through the stomata and can interfere with carbon gain (photosynthesis) and allocation of carbon within the plant, making fewer carbohydrates available for plant growth, reproduction, and/or yield (2020 PA, section 4.3.1 and 2013 ISA, p. 1-15).,  Ozone can impact a variety of commercial and ecologically important species throughout the United States.  These include forest tree and herbaceous species as well as crops.  Such effects at the plant scale can also be linked to an array of effects at larger spatial scales and higher levels of biological organization, causing impacts to ecosystem productivity, water cycling, ecosystem community composition and alteration of below-ground biogeochemical cycles (2020 PA, section 4.3.1 and 2013 ISA, p. 1-15)..  With the data sets available to the Agency, here, we focus on selected forest tree species.
      Assessing the impact of ozone on forests in the United States involves understanding the risk to tree species from ozone concentrations in ambient air and accounting for the prevalence of those species within the forest.  Across several reviews of the ozone NAAQS and based on longstanding body of scientific evidence, EPA has evaluated concentration-response functions which relate ozone exposure to growth-related effects in order to consider the risk of ozone-related growth impacts on forest trees (2020 PA, section 4.3.3, 2013 ISA and 2020 ISA).  For this purpose, EPA has focused on cumulative, concentration-weighted indices of exposure, such as the W126-based cumulative exposure index (2020 PA, section <IP_ADDRESS>.1, 2020 ISA, section ES.3).  Measured ozone concentrations in ambient air of the United States are used to calculate the W126-based index as the annual maximum 3-month sum of daytime hourly weighted ozone concentrations, averaged over 3 consecutive years. The sensitivity of different trees species varies about the growth impacts of ozone exposure. Based on well-studied datasets relating W126 index to reduced growth, exposure response functions have been developed for 11 tree species (2020 PA, section <IP_ADDRESS>.2 and Figure 4-3 and 2013 ISA, section 9.6).  For these species, the impact from ozone exposure has been determined by exposing seedlings to different levels of ozone concentrations over one or more seasons (which have been summarized in terms of W126 index) and measuring reductions in growth (which are then summarized as "relative biomass loss"). The magnitude of ozone impact on a forest community will depend on the prevalence of different tree species of relatively more versus less sensitivity to ozone and the abundance in the community.
      The most common tree species in the eastern United States, where the benefits from this rule will be most pronounced, are black cherry (Prunus serotina), yellow or tulip-poplar (Liriodendron tulipifera), sugar maple (Acer saccharum), eastern white pine (Pinus strobus), Virginia Pine (Pinus virginiana), red maple (Acer rubrum), and quaking aspen (Populus trenuloides).  Since 2008, EPA has assessed the impact of ozone on these tree species within the eastern United States for the period from 2000 to 2018 as part of the Clean Air Market Division (CAMD) annual power sector programs progress report.  Over this time period ozone concentrations have improved substantially because of various emission reduction programs, such as NBP, CAIR, CSAPR, CSAPR Update, and other local and mobile source reductions such as Tier2 and Tier3 rules. Past EPA assessments have shown that the improvements in ozone are evident both for the regulatory metric, 3-year average of 4[th] highest 8-hr daily maximum ozone concentration, and for the W126 metric.     In forests where certain sensitive species dominate the forest community, the estimates of relative biomass loss from ozone have decreased substantially. However, for the period from 2017 - 2019, the eastern United States still has areas with up to 11.5% estimated relative biomass loss  for the seven tree species  -  black cherry, yellow poplar, sugar maple, eastern white pine, Virginia pine, red maple, and quaking aspen (Figure F-1).
      Ozone levels are expected to continue to decrease through 2024 based on model projection of the impacts on ozone concentrations resulting from baseline "on the books" control programs as well as by emission reductions under this rule.  As ozone declines, estimates of relative biomass loss of these trees' species will also decline as they have from 2000 to 2019, indicating increased protection of forest ecosystems and resources.  Under this rule, ozone concentrations are expected to decline faster than without the rule (e.g., under the base case).  While EPA does not have the tools  to quantify the expected level of improvement at this time, based on the previous relationships between ozone design values and W126 determined as part of the review of the 2020 ozone NAAQS (2020 PA, section 4D.3.2.3 and Table 4D-12), W126 values are expected to improve as design values decrease.  As described in the preamble, the rule is expected to decrease design values by 0.17 ppb, on average, in 2021. The reductions from this rule are likely to provide further protection to natural forest ecosystems by reducing the potential for ozone-related impacts.

Figure F-1: Estimated Black Cherry, Yellow Poplar, Sugar Maple, Eastern White Pine, Virginia Pine, Red Maple, and Quaking Aspen Biomass Loss due to Ozone Exposure for 2016-2018. See the annual progress report at https://www3.epa.gov/airmarkets/progress/reports/index.html

Appendix A:  State Emission Budget Calculations and Engineering Analytics
See Excel workbook titled "Final Rule State Emission Budget Calculations and Engineering Analytics" on EPA's website and in the docket for this rulemaking

 Appendix B:  Description of Excel Spreadsheet Data Files Used in the AQAT
      EPA placed the Ozone_AQAT_Final.xlsx Excel workbook file in the Revised CSAPR Update docket that contains all the emission and CAMx air quality modeling inputs and resulting air quality estimates from the AQAT.  The following bullets describe the contents of various worksheets within the AQAT workbook:

State-level emissions
 "2021_EGU" through "2026_EGU" contain EGU emissions measurements and estimates for each state.  Various columns contain the 2016 and 2019 OS measured emissions, CSAPR Update Budgets, and then emissions for the engineering base along with each of the cost thresholds.
  "2016fh1" contains state and source-sector specific ozone-season NOX emission totals for the 2016 base case modeled in CAMx.
 "2023fh1" contains state and source-sector specific ozone-season NOX emission totals for the 2023 base case with EGU estimates from IPM modeled in CAMx.
 "2023fh1_eng" contains state and source-sector specific ozone-season NOX emission totals for the 2023 base case with EGU estimates from engineering analysis that could be used  in CAMx.
 "2028fh1" contains state and source-sector specific ozone-season NOX emission totals for the 2028 base case with EGU estimates from IPM modeled in CAMx.
 "AQM_EGU_emiss" has a breakdown of the point EGU emission inventory used in the air quality modeling, for the units with CEMs and those that don't (nonCEMs).
 "calib_emiss" has the total anthropogenic emissions by state for each of the base cases modeled in CAMx.  This worksheet also contains the fraction change for each of these scenarios relative to the 2023fh1 base case modeled in CAMx.
 "2021_emiss_total", "2022_emiss_total", "2023_emiss_total", "2024_emiss_total", "2025_emiss_total", "2026_emiss_total"  each of these worksheets reconstructs total anthropogenic emissions for the year, with various EGU emission inventories for different cost threshold (including the engineering base case).  The total anthropogenic emissions can be found for each state in columns BW through CE.  These totals are then compared to the 2023fh1 emission level (column CE) to make a fractional change in emissions in columns CF through CN.  Non-EGU emissions change and fractional change (inclusive of EGU changes at $1,800/ton) are found in columns CO and CP, respectively

Air quality modeling design values and contributions from CAMx

 "2023_contribs" contains average and maximum design values as well as state by state contributions for the 2023fh1 base case modeled in CAMx.
 "2028fh1 DVs" contains average and maximum design values for each receptor in 2028 with EGU estimates from IPM.

Calibration factor creation and assessment
 "calib_2016" includes the calculation of the calibration factor based on the 2023 contributions, and percent change of 2016 emissions relative to 2023 emissions. The calibration factor can be found in column BM.
 "calib_2028" includes the calculation of the calibration factor based on the 2023 contributions, and percent change of 2028 emissions relative to 2023 emissions. The calibration factor can be found in column BM.
 "calib comp" includes a summary of the three calibration factors (one based on 2016and one based on 2028).

Air quality estimates
 "Summary DVs" contains the average and maximum design value estimates (rounded to two decimal places) for receptors that were nonattainment or maintenance in the 2021 base case interpolation modeling.  Values for each year (2021 through 2015), for each cost threshold are shown.  Grey or black filled cells are not considered viable scenarios for technical or policy reasons.  Each scenario has the cost threshold shown for that run the linked and unlinked states.  Adjustment to cells J27 and J28will result in interactive adjustment for the other worksheets and will adjust the average design values in column J and maximum design values in column X.
 "scenario_2021" through "scenario_2025" contains the average and maximum design value estimates (as well as the individual state's air quality contributions) for a particular scenario identified in cells G2 and G3.  The fractional emission changes for each of the linked and unlinked states are shown in rows 2 and 3.
 "scenario_2021_sens" and "scenario_2022_sens" contains the average and maximum design value estimates (as well as the individual state's air quality contributions) for a particular EGU scenario identified in cells G2 and G3 where the remainder of the emission inventory was created by interpolating between a projected 2021 inventory and the 2023 inventory.  The fractional emission changes for each of the linked and unlinked states are shown in rows 2 and 3.  The fractional emission changes for these scenarios are calculated in "2021_emiss_total_sens" and "2021_emiss_total_sens".
 "straightline_2021" through "straightline_2026" contains the average and maximum design value estimates (as well as the individual state's air quality contributions) for the emissions scenario that is a linear interpolation of the emissions between the 2016 base case and the 2023fh1 base case (or between the 2023fh1 base case and 2028fh1 base case).
  "control_2021" through "contol_2025" contains the average and maximum design value estimates (as well as the individual state's air quality contributions) for a particular scenario identified in cells G2 and G3.  States that are "linked" to any receptor in the geography are assigned the values in row 2 while nonlinked states are assigned the values in row 3.  Note that, as the "home" States, Texas and Connecticut are both assigned the "linked" State level of reductions.
 "scenario_2024 alt calibration" contains the average and maximum design value estimates (as well as the individual state's air quality contributions) for a particular scenario identified in cells G2 and G3.  The fractional emission changes for each of the linked and unlinked states are shown in rows 2 and 3.  This uses the calibration factor based on the 2016 air quality modeling, rather than the calibration factor based on the 2028 air quality modeling.
 The individual cost level worksheets labeled: "New_SCR"; "New_SNCR"; "SCR_SNCR_LNB"; "SCR_SNCR"; "SCR_LNB"; "SCR"; "$500"; "straightline_base"; and "eng_base" contain static air quality contributions and design value estimates for the four receptors of interest for each of the years.

Appendix C:  IPM Runs Used in Transport Rule Significant Contribution Analysis
      Table C-1 lists IPM runs used in analysis for this rule.  The IPM runs can be found in the docket for this rulemaking under the IPM file name listed in square brackets in the table below.

Table Appendix C-1. IPM Runs Used in Transport Rule Significant Contribution Analysis
Run Name
[IPM File Name]
Description
Air Quality Modeling Base Case

EPA617_BC_75L
Model run used for the air quality modeling base case at steps 1 and 2, which includes the national Title IV SO2 cap-and-trade program; NOX SIP Call; the Cross-State Air Pollution trading programs, and settlements and state rules.  It also includes key fleet updates regarding new units, retired units, and control retrofits that were known by Fall of 2019.
Illustrative Base Case

EPA617_CURR_1g
Model run used as the base case for the Illustrative Analysis of cost threshold analyses. Based on the air quality modeling base case, but with projected retirements and retrofits in 2021 limited.
Illustrative Base Case with optimization technology + LNB upgrade

EPA617_CURR_5d
Imposes state-level generation constraints starting in 2021 for fossil-fuel fired units greater than 25 MW that is equal to Illustrative Base Case levels. Also assumes optimization of existing post-combustion controls and upgrade of combustion controls if mode 3<mode 1.
Illustrative $1,600 per ton Cost Threshold

EPA617_CURR_3d
Same as the Illustrative Base Case with optimization technology + LNB upgrade, but with $1600/ OS NOx ton price signal applied in the ozone season.
Illustrative $3,900 per ton Cost Threshold

EPA617_CURR_4d
Same as the Illustrative Base Case with optimization technology + LNB upgrade, but with $3900/OS NOx ton price signal applied in the ozone season.
Illustrative Base Case with optimization technology, LNB, + SNCR retrofit

EPA617_CURR_8d
Same as Illustrative Base Case with optimization technology + LNB upgrade , but starting in 2025, for coal fired units greater than 100 MW and lacking a post combustion NOx control (SCR or SNCR), a 25% reduction to their ozone season NOx emission rate with a floor of 0.07 lbs/MMBtu is applied.
Illustrative $5,800 per ton Cost Threshold

EPA617_CURR_6d
Same as Illustrative Base Case with optimization technology, LNB, + SNCR retrofit, but with $5,800 OS NOx ton price signal applied in the ozone-season
Illustrative Base Case with optimization technology, LNB, + SCR retrofit

EPA617_CURR_9d
Same as Illustrative Base Case with optimization technology + LNB upgrade, but starting in 2025, for coal fired units greater than 100 MW and lacking a post combustion NOx control (SCR or SNCR), a 90%reduction to their ozone season NOx emission rate with a floor of 0.07 lbs/MMBtu is applied.
Illustrative $9,600 per ton Cost Threshold

EPA617_CURR_7d
Same as Illustrative Base Case with optimization technology, LNB, + SCR retrofit, but with $9,600/OS NOx ton OS ton price signal applied in the ozone-season.
Illustrative $500 per ton Cost ThresholdEPA617_CURR_10d
Same as Illustrative Base Case, but with $500/OS NOx ton OS ton price signal applied in the ozone-season.
Illustrative More Stringent Policy Case

EPA617_CURR_13
Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting $1600 per OS NOx ton through 2023 and $9600 per OS NOx ton for 2025 model run year, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Illustrative LessStringent Policy Case

EPA617_CURR_12
Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting $500 per OS NOx ton  starting in 2021, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Proposed Policy Scenario

EPA617_CURR_14
Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting $1600 per OS NOx ton  starting in 2021, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Final Illustrative More Stringent Policy Case
EPA617_CURR_20e
Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting optimization of existing controls and combustion control upgrade through 2023, and SCR retrofit in model run year 2025 and beyond, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Final Illustrative LessStringent Policy Case
EPA617_CURR_21b

Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting $500 per OS NOx ton  starting in 2021, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Final Policy Scenario
EPA617_CURR_19d
Same as Illustrative Base Case, but with ozone season emissions budgets with variability limits applied for the 12 states reflecting $1600 and $1800 per OS NOx ton  starting in 2021and 2022 respectively, along with a regional cap equal to the sum of the 12 states' budgets for each year.
Final Policy Sensitivity
EPA617_CURR_22
Same as Final Policy Scenario used for RIA, but with state emission budgets reflecting $1800 per ton stating in 2021
Base Case with Additional Nuclear Retirements  -  Sensitivity
EPA617_CURR_18b
Same as Illustrative Base Case, but with potential Dresden/Byron nuclear retirements included.
Final Policy Scenario Sensitivity  -  with additional nuclear retirements
EPA617_CURR_23
Same as Final Policy Scenario assumptions, but applied to the base case with additional nuclear retirements to reflect potential Dresden/Byron nuclear retirements.

Appendix D:  Ozone-Season NOX Emissions Limits for IPM Modeling

Table Appendix D-1. State and Regional Caps for IPM Final Case Analysis for the Final Rule

                                  Policy Case

                        Less Stringent Case ($500/ton)

                       More Stringent Case ($9,600/ton)

                       Assurance Level (121% of Budget)

                       Assurance Level (121% of Budget)

                       Assurance Level (121% of Budget)

                                                                          2021*
                                                                           2023
                                                                           2025

                                                                           2021
                                                                           2023
                                                                           2025

                                                                           2021
                                                                           2023
                                                                           2025
Illinois
                                                                         11,129
                                                                          9,896
                                                                          9,751

                                                                         11,311
                                                                         10,155
                                                                         10,009

                                                                         11,129
                                                                          9,896
                                                                          8,338
Indiana
                                                                         15,833
                                                                         15,189
                                                                         11,573

                                                                         18,969
                                                                         18,366
                                                                         14,621

                                                                         15,833
                                                                         15,189
                                                                         10,201
Kentucky
                                                                         18,521
                                                                         17,001
                                                                         17,001

                                                                         18,883
                                                                         18,883
                                                                         18,883

                                                                         18,521
                                                                         17,001
                                                                         11,827
Louisiana
                                                                         18,621
                                                                         17,929
                                                                         17,929

                                                                         18,670
                                                                         18,670
                                                                         18,670

                                                                         18,621
                                                                         17,929
                                                                         15,272
Maryland
                                                                          1,814
                                                                          1,532
                                                                          1,631

                                                                          1,816
                                                                          1,533
                                                                          1,633

                                                                          1,814
                                                                          1,532
                                                                          1,414
Michigan
                                                                         15,406
                                                                         12,070
                                                                         11,841

                                                                         15,882
                                                                         12,567
                                                                         12,327

                                                                         15,406
                                                                         12,070
                                                                          8,887
New Jersey
                                                                          1,517
                                                                          1,517
                                                                          1,517

                                                                          1,629
                                                                          1,629
                                                                          1,629

                                                                          1,517
                                                                          1,517
                                                                          1,521
New York
                                                                          4,133
                                                                          4,139
                                                                          4,117

                                                                          4,190
                                                                          4,196
                                                                          4,174

                                                                          4,133
                                                                          4,139
                                                                          3,989
Ohio
                                                                         11,725
                                                                         11,825
                                                                         11,825

                                                                         18,740
                                                                         18,839
                                                                         18,839

                                                                         11,725
                                                                         11,825
                                                                         11,158
Pennsylvania
                                                                         10,139
                                                                         10,131
                                                                         10,131

                                                                         14,287
                                                                         14,285
                                                                         14,285

                                                                         10,139
                                                                         10,131
                                                                          9,499
Virginia
                                                                          5,583
                                                                          4,816
                                                                          4,432

                                                                          5,640
                                                                          5,272
                                                                          4,866

                                                                          5,583
                                                                          4,816
                                                                          3,853
West Virginia
                                                                         16,560
                                                                         15,589
                                                                         15,589

                                                                         18,170
                                                                         18,170
                                                                         18,170

                                                                         16,560
                                                                         15,589
                                                                         12,787

Region Cap (Budget Total)
                                                                        108,248
                                                                        100,525
                                                                         96,974

                                                                        122,468
                                                                        117,822
                                                                        114,138

                                                                        108,248
                                                                        100,525
                                                                         81,609

Appendix E: Generation Shifting Analysis

Table Appendix E-1. Tons of EGU NOX Reduction Potential from Shifting Generation Compared to Adjusted Historical Baseline Emissions.

Appendix F: Feasibility Assessment for Engineering Analytics Baseline

Similar to CSAPR Update Final Action, EPA analyzed and confirmed that the assumed fleet operations in its baseline emissions and budget estimates were compatible with future load requirements by verifying that new units in addition to the existing fleet would provide enough generation, assuming technology-specific capacity factors, to replace the retiring generation expected to occur in years 2021 through 2024. EPA assessed generation adequacy specific to the 12 states covered under this action.  EPA uses these observations to determine whether any assumed replacement generation from the existing fleet is necessary to offset the announced retirements and continue to satisfy electricity load.  Additionally, EPA looked at whether the combination of new units (both fossil and non-fossil) provide sufficient new generation to replace retiring generation. In this case, EPA found that the new unit generation from fossil and renewable generation would exceed the generation from retiring units in all three scenarios examined, indicating that no further replacement generation from existing units is needed. Moreover, EPA found the change in generation from the covered fossil units to be within the observed historical trend. EPA updated its analysis below at final rule taking into account the latest announcements and commenter data on new units and retirements. EPA's conclusion was further supported by its updated analysis and data.

 EPA first identified the collective baseline heat input and generation from the 12 states covered in this action and compared it to historical trends for these same states (Scenario 1).  This illustrated that the assumed heat input and generation from fleet turnover was well within with recent historical trends (see tables Appendix F-1,Appendix F-2, and Appendix F-3 below).
 EPA then compared the collective baseline heat input and generation from the 12 states covered in this action to a scenario where fossil generation remains at 2019 levels instead of continuing to decline (Scenario 2).
 Finally, EPA identified the 2020 Energy Information Administration's Annual Energy Outlook (EIA AEO) annual growth projections from 2019 through 2024 total electricity demand levels (0.8%) from its reference case, and estimated an upperbound future year scenario where covered fossil generation grew at levels matching this fleet-wide total growth rate (Scenario 3).
 EPA's assessment illustrates the amount of generation in its baseline, factoring in retirements and new fossil units, is more than sufficient to accommodate all three scenarios. For instance, generation from covered fossil sources in these 12 states has dropped at an average rate greater than 2% per year between 2016 and 2019 (410 TWh to 384 Twh). However, EPA's assumed baseline generation from covered fossil sources for the 12 states reflects a rate of decline less than 2% per year. See Table Appendix F-2.
 EPA then identified new RE capacity under construction, testing, or in site prep by 2021. For years beyond 2021, EPA also identified new RE capacity that was planned but with regulatory approvals pending for years 2022 and beyond (as this capacity is unlikely to have yet started construction).
 EPA calculated and added the RE generation values to the fossil baseline to estimate future year generation in the state (see Table Appendix F-3). EPA used a capacity factor of 42.7% for wind, 21.6% for solar, and 65% for NGCC.
 Using these technology-specific capacity factors based on past performance and IPM documentation, EPA anticipated over 20 TWh from new generation already under construction or being planned with regulatory approval received. This combined with the baseline generation from existing units exceeds the expected generation load for the 12 states under all three scenarios.

 Not only is the future baseline generation level assumed in EPA's engineering analysis well within the recent historical fossil generation trend (See Table Appendix F-2) on its own (which illustrates no need for replacement generation), but it is also exceeds an upper bound analysis for future covered fossil generation that assumes 0.8% growth from the existing fossil fleet (scenario 3). Moreover, the potential new generation from RE (over 7 TWh) when added to the baseline fossil generation values further increases the amount by which baseline generation exceeds the historical fossil generation for the 12 states with assumed annual growth of 0.8%. This indicates that available capacity and generation assumed would serve load requirements in this upper bound scenario.

      Not included in the tables below nor in EPA's baseline, but listed in the latest EIA 860m is even more planned NGCC combined cycle for years 2023 and 2024 that is pending regulatory approval. Assuming some of this (low emitting generation) becomes available in the outer years, that constitutes additional generation that exceeds EPA's upperbound generation levels below  -  further bolstering the observation that no replacement generation from existing units needs to be assumed to fill generation from retiring units.

Table Appendix F-1: Heat Input Change Due to Fleet Turnover (Historical and Future)

             Reported Heat Input from Covered Fossil Units (TBtu)

                 Assumed Heat Input from Covered Fossil (TBtu)

                                                                           2016
                                                                           2017
                                                                           2018
                                                                           2019

                                                                           2021
                                                                           2022
                                                                           2023
                                                                           2024
Illinois
                                                                          383.4
                                                                          333.2
                                                                          379.3
                                                                          311.8

                                                                            267
                                                                            267
                                                                            270
                                                                            266
Indiana
                                                                          415.6
                                                                          379.1
                                                                          432.3
                                                                          356.5

                                                                            357
                                                                            352
                                                                            356
                                                                            297
Kentucky
                                                                          360.2
                                                                          319.1
                                                                          351.3
                                                                          313.8

                                                                            287
                                                                            287
                                                                            287
                                                                            287
Louisiana
                                                                          331.8
                                                                            302
                                                                          312.2
                                                                          317.4

                                                                            344
                                                                            345
                                                                            345
                                                                            345
Maryland
                                                                          108.7
                                                                           76.9
                                                                           95.7
                                                                             83

                                                                             82
                                                                             79