2024-17471. Air Plan Approval; North Dakota; Approval of Air Quality Implementation Plans; Regional Haze State Implementation Plan; Regional Haze Five Year Progress Report and Nitrogen Oxides Best Available Retrofit Technology Determination for Coal ...

Table 1—2022 SIP Submittal Cost of Compliance and Incremental Cost of Compliance

Control technology	Performance level (lb/MMBtu)	Annualized emission reduction (tpy)	Annualized total cost ($)	Cost of compliance ($/ton)	Incremental cost of compliance ($/ton)	Incremental cost of SCR over SNCR ($/ton)
Baseline, LNC3 with DryFining TM	0.18
LNC3+	0.13	1,162	793,418	683
LNC3+ w/SNCR	0.10	1,850	6,194,244	3,348	7,850
LNC3+ w/SCR	0.08	2,309	16,122,491	6,983	13,368	21,645
LNC3+ w/SCR	0.06	2,767	17,391,169	6,284	10,339	12,206

2. Energy and Non-Air Quality Environmental Impacts of Compliance

North Dakota identified the production of sulfuric acid as a side reaction with the SCR process chemistry. Sulfuric acid, which is not captured within the boiler or associated downstream emission control, is released to the atmosphere as sulfuric acid mist (SAM). North Dakota noted that SAM is emitted as aerosol particles that contribute to visibility impairment.^[47] Because these emissions contribute to impairment, North Dakota considered the visibility impacts of SAM emissions in the analysis of visibility improvements from SCR and the costs of controlling SAM emissions in the SCR control cost analysis. Using the calculation procedures in a 2018 publication from Electric Power Research Institute, North Dakota estimated SAM emissions of approximately 415 tons per year per unit as a result of the SCR catalyst with a 5% oxidation rate at Coal Creek Station.^[48] North Dakota also noted that a low-dust SCR system would require a fuel-fired reheat burner system, which could result in additional energy usage and additional emissions of NO_X and other pollutants.^[49] North Dakota estimated water demands for SNCR to be 70-80 million gallons per year.^[50] North Dakota noted the potential for ammonia slip as a result of these technologies, which could result in increased nitrogen in the scrubber, which would eventually be routed to evaporation ponds.^[51] Additionally, the Great River Energy BART analysis included an evaluation of potential adverse impacts of ammoniated fly ash.^[52] The report estimated that an additional 92,000 tons of fly ash would need to be disposed of in a landfill annually, which represents an additional 81 percent increase in fly ash disposal.^[53]

3. Pollution Control Equipment at the Source

North Dakota's Updated BART analysis takes into account existing controls, including DryFining^TM and other combustion controls. At the time of the initial BART modeling, LNC3 was operational on both Units 1 and 2. DryFining^TM became operational at Units 1 and 2 in 2010. LNC3+ became operational at Unit 2 in 2010, and was installed on Unit 1 in the second quarter of 2020.^[54] Though North Dakota did not incorporate LNC3+ into the baseline, the State did consider the existing LNC3+ by performing an incremental cost analysis looking at the standalone cost of implementing SNCR, the next most stringent control, relative to the existing ( print page 66020) LNC3+. North Dakota also performed incremental analyses looking at the standalone cost of SCR relative to LNC3+. Per the EPA's BART guidelines, which advise that incremental costs should be calculated relative to the next most stringent control option,^[55] North Dakota also performed incremental cost analyses looking at the standalone cost of SCR relative to SNCR.

4. Remaining Useful Life

Remaining useful life was not considered by North Dakota because Coal Creek is expected to operate beyond the life of the control equipment. Therefore, North Dakota evaluated the controls according to the remaining useful life timeframes listed in the EPA's Control Cost Manual: 30 years for SCR and 20 years for SNCR.^[56]

5. Visibility Improvement

North Dakota considered California Puff (CALPUFF) dispersion modeling conducted by Coal Creek to assess the potential visibility improvement from the use of additional NO_X BART controls at the Lostwood and Theodore Roosevelt National Park Class I areas.^[57] Table 2 shows the baseline visibility impairment values associated with Modeling Scenario 1 (North Dakota's baseline scenario). Modeling Scenario 1 reflects emissions rates associated with the post-SO₂ BART approved controls (including DryFining^TM) and LNC3 controls for NO_X . Table 3 shows the projected incremental visibility impact of potential NO_X BART controls on Units 1 and 2 in addition to the assumed baseline (Modeling Scenario 1). Modeling Scenario 2 considers the addition of LNC3+ to the baseline, Scenario 3 considers LNC3+ with the addition of SNCR, and Scenarios 4-6 consider LNC3+ with the addition of SCR at three different oxidation rates (5%, 2.5%, and 0%).

Table 2—Model Scenario 1 Baseline Visibility Impairment in Deciviews

Year	Theodore Roosevelt South Unit 58	Theodore Roosevelt north unit	Theodore Roosevelt Elkhorn Ranch unit	Lostwood
2000	0.66	0.65	0.60	0.92
2001	0.47	0.57	0.53	0.87
2002	1.28	1.15	0.99	0.69

Table 3—Coal Creek Station Incremental Visibility Impact of Modeling Scenarios 2-6 in Deciviews ⁵⁹

[Negative numbers indicate decreases in visibility impairment, positive numbers indicate increases in visibility impairment]

Modeling scenario	NO X control technology		Lostwood	Theodore Roosevelt
2	Addition of LNC3+		−0.15	South Unit North Unit Elkhorn Ranch Unit	−0.13 −0.12 −0.12
3	LNC3+ with addition of SNCR		−0.06	South Unit North Unit Elkhorn Ranch Unit	−0.07 −0.09 −0.07
4	LNC3+ with addition of SCR.60	5% Oxidation Rate	0.17	South Unit North Unit Elkhorn Ranch Unit	0.04 −0.02 0.00
5	LNC3+ with addition of SCR	2.5% Oxidation Rate	0.01	South Unit North Unit Elkhorn Ranch Unit	−0.07 −0.11 −0.08
6	LNC3+ with addition of SCR	0% Oxidation Rate	−0.14	South Unit North Unit Elkhorn Ranch Unit	−0.17 −0.21 −0.16

The modeling results in table 3 show the visibility benefits of adding LNC3+ to the baseline (Scenario 2), and then the incremental, not total, visibility benefit of adding SNCR to the LNC3+ control scenario (Scenario 3) and SCR to the LNC3+ control scenario (Scenarios 4-6). The “total” visibility benefit of LNC3+ plus SNCR can be derived by adding the deciview improvement values for Scenarios 2 plus 3. And the “total” visibility benefit of LNC3+ plus SCR can be derived by adding the deciview improvement values for Scenarios 2 plus 4, 2 plus 5, or 2 plus 6 respectively. Note that due to the assumption of 5% and 2.5% SO₂ to SO₃ oxidation rates in Scenarios 4 and 5, there are several instances of net increases in visibility impairment. Those are represented as positive values. North Dakota ultimately concluded that none of the NO_X BART controls modeled were shown to have a “significant” impact on improving visibility in North Dakota's Class I areas.

( print page 66021)

6. BART Demonstration

After considering each of the five BART factors, States must demonstrate how those factors were taken into consideration in making a BART determination.^[61] After consideration of the five factors, North Dakota identified LNC3+ as BART for Coal Creek Units 1 and 2.^[62] Due to the inherent variability with shorter-term operations due to unit load swings and variable sodium concentrations in North Dakota lignite coal, North Dakota proposed a limit of 0.15 lb/MMBtu NO_X 30-day rolling average in lieu of the 0.13 lb/MMBtu NO_X annual rate to account for this variability. North Dakota found that the other potential controls evaluated, SNCR and SCR, were not reasonable to select for BART due to high cost and the potentially significant non-air quality impacts described in sections III.C.1. and III.C.2. above.^[63]

In summary, North Dakota concluded that the BART analysis demonstrates that the currently installed NO_X emissions controls (LNC3+) on Units 1 and 2 constitute NO_X BART for Coal Creek Units 1 and 2. North Dakota rejected additional controls that were considered, citing cost, feasibility concerns, potential non-air quality impacts, and low visibility improvements as the most influential factors in its rejection of additional controls.^[64] Therefore, North Dakota's 2022 SIP submittal requires emissions limits of 0.15 lb/MMBtu (30-day rolling average) associated with the operation of LNC3+ on Units 1 and 2 as the State's BART determination for Coal Creek.

D. January 12, 2015 Progress Report SIP Submittal

On January 12, 2015, North Dakota submitted its 2015 progress report to the EPA as a SIP revision. Two Class I areas are located in North Dakota: Lostwood Wilderness Area and Theodore Roosevelt National Park. The Theodore Roosevelt National Park Class I area is composed of three separate units: North Unit, Elkhorn Ranch Unit, and South Unit. In the first planning period, emissions from North Dakota sources were also found to be contributing to visibility impairment at nearby Boundary Waters Canoe Area Wilderness Area and Voyageurs National Park in Minnesota, Isle Royale National Park and Seney National Wildlife Refuge Wilderness Area in Michigan, Medicine Lake National Wildlife Refuge Wilderness Area and U.L. Bend National Wildlife Refuge Wilderness Area in Montana, and Badlands National Park and Wind Cave National Park in South Dakota.^[65]

North Dakota consulted with other States through regular participation in the Western Regional Air Partnership (WRAP).^[66] In developing the 2015 progress report, North Dakota relied on the technical tools, policy documents, and other products that other WRAP States used to develop their regional haze plans. The WRAP Implementation Work Group was one of the primary collaboration mechanisms. Additionally, North Dakota consulted directly with the State of Minnesota through the Minnesota Pollution Control Agency. Discussions with neighboring States included the review of major contributing sources of air pollution.^[67]

In the first planning period, the EPA required the following for BART: SO₂ emissions limits for Coal Creek Units 1 and 2 and Heskett Station Units 1 and 2 ^[68] as well as NO_X emissions limits for Coyote Station Unit 1,^[69] Milton R. Young Units 1 and 2,^[70] Leland Olds Station Unit 2,^[71] Stanton Station,^[72] and Antelope Valley Station Units 1 and 2,^[73] while the NO_X BART requirements at Coal Creek Units 1 and 2 remained outstanding.

North Dakota's 2015 progress report details the progress made in the first planning period toward implementation of the long-term strategy outlined in its 2010 SIP submittal, the visibility improvement measured at the Class I areas affected by emissions from North Dakota, and a determination of the adequacy of the State's existing regional haze SIP.

E. North Dakota's Five-Year Progress Report Determination

In its 2015 Progress Report, North Dakota included a description of the status of implementation of the measures included in the first planning period implementation plan, including current emissions rates, BART and reasonable progress limits, and implementation dates.^[74] North Dakota also included a breakdown of its species contribution to impairment in both in-state and out-of-state Class I areas.^[75] Further, North Dakota included a list of emissions reductions that have occurred as a result of Regional Haze Round 1 SIP control requirements.^[76] North Dakota's first planning period implementation plan includes the following key measures: implementation of BART and reasonable progress for sources subject to this analysis and federal programs to cut on-road emissions and emissions from industrial boilers, combustion turbines, and internal combustion engines.^[77]

Additionally, North Dakota included an assessment of visibility conditions and changes on least-impaired days and most-impaired days for both Class I areas within the State (Lostwood Wilderness Area and Theodore Roosevelt National Park), including 5-year averages representing the most recent 5-year period preceding the required date of the progress report.^[78] North Dakota also showed the difference between current (at the time of progress report development) visibility conditions for the most impaired and least impaired days and baseline visibility conditions, as well as the change in visibility impairment for the most impaired and least impaired days over the period since the period addressed in the most recent plan.^[79] North Dakota compared the baseline average of visibility impairment to both an average from 2005-2009 and an average from 2008-2012.^[80]

Further, North Dakota included an analysis tracking the change over the period since the period addressed in the most recent plan in emissions of pollutants contributing to visibility impairment from all sources and activities within the State—these numbers are also broken down by ( print page 66022) source category.^[81] Here, North Dakota included 2011 data, data from the most recent triennial reporting requirements as of the time of progress report development.^[82] Further, North Dakota also included 2018 emissions projections to show additional progress that was expected to be achieved by the State by 2018.^[83]

North Dakota also included an assessment of changes in anthropogenic emissions within and outside of the State that have occurred since the period addressed in the most recent plan.^[84] Here, North Dakota noted that the most obvious source category where emissions have increased is in oil and natural gas production, due to increased development of the Bakken formation, an area in western North Dakota with rich oil and gas reserves.^[85] Within this sector, North Dakota notes that the pollutant with the largest increase is volatile organic compounds (VOC).^[86] North Dakota also notes an increase in NO_X emissions in the oil and gas sector, though that increase (6,000 to 17,000 tpy) is outweighed by an approximate decrease of 32,000 tons of NO_X per year on a statewide (all sectors) basis.^[87] North Dakota States that the increase in VOC and NO_X emissions does not appear to be impacting ozone concentrations in Class I areas or any part of North Dakota.^[88] North Dakota points to a plan to reduce natural gas flaring in oil fields, which was adopted by the North Dakota Industrial Commission in April 2014, as support for the expected reduction of NO_X and VOC.^[89] North Dakota notes that this plan is expected to reduce the natural flaring rate of 36% of all gas produced to 15% in two years, 10% within six years, and eventually to 5%.^[90] This reduction in flaring is expected to reduce NO_X and VOC emissions. Considering these changes in emissions and expected reductions in NO_X and VOC emissions due to a reduction in flaring, North Dakota concludes that there is no evidence at this time that the increase in oil and gas activity (or any other sector) in North Dakota is impeding progress towards the visibility goal.^[91]

In its 2015 Progress Report, North Dakota includes an assessment of whether the current implementation plan elements are sufficient to enable North Dakota, and States with Class I areas impacted by North Dakota, to meet their reasonable progress goals for the first planning period.^[92] First, North Dakota noted that Theodore Roosevelt National Park had met its reasonable progress goals for the last five years at the time of development of the 2015 Progress Report.^[93] North Dakota also noted that Lostwood Wilderness Area had met its reasonable progress goals in the last 2 out of 3 years at the time of development of the 2015 Progress Report.^[94] North Dakota pointed to a decrease in SO₂ and NO_X emissions from the State that occurred from 2002 to 2011.^[95] Further, North Dakota notes that on the whole, visibility-impairing emissions were projected to decrease by 2018. While NO_X emissions are projected to increase by 20,343 tons, SO₂ emissions are projected to decrease by 36,296 tons.^[96] This amounts to an overall reduction of 15,953 tpy of visibility-impairing pollutants by 2018.^[97] In sum, North Dakota determined that the existing implementation plan elements are sufficient to meet reasonable progress goals for both Theodore Roosevelt National Park and Lostwood Wilderness Area.^[98] North Dakota further noted that the decrease in visibility-impairing NO_X and SO₂ emissions from the State will also help out-of-state Class I areas meet their reasonable progress goals.^[99] As noted earlier in this section, the main increase in emissions during the period covered by the 2015 Progress Report occurred as an increase in NO_X and VOC emissions in the oil and gas sector.^[100] North Dakota notes that these pollutants are typically emitted at lower elevations and produce a more localized impact.^[101] To assess impacts on its nearest out-of-state Class I area (Medicine Lake Wilderness Area in Montana), North Dakota compared Medicine Lake to nearby Lostwood Wilderness Area, noting that both Class I areas are upwind from North Dakota oil and gas sources and are thus unlikely to be impeded from meeting reasonable progress goals due to emissions from North Dakota.^[102] North Dakota ultimately concluded that its emissions will not impede the achievement of reasonable progress goals in in-state or out-of-state Class I areas.^[103]

North Dakota also included an assessment of its visibility monitoring strategy. North Dakota stated that it relies on the Interagency Monitoring of Protected Visual Environments (IMPROVE) program for its monitoring strategy.^[104] North Dakota concluded that there is no change needed to the monitoring strategy at the time the 2015 progress report was developed.^[105] North Dakota included a determination of the adequacy of its existing implementation plan, concluding that based on the information provided in North Dakota's 2015 Progress Report, the existing implementation plan is sufficient to achieve established goals for visibility improvement and emissions reduction.^[106] Lastly, North Dakota noted that it provided an opportunity for consultation with FLMs with regard to the 2015 Progress Report on June 25, 2014 by providing FLMs a copy of the 2015 Progress Report. The 2015 Progress Report was distributed to the National Park Service, the U.S. Fish and Wildlife Service, and the U.S. Forest Service. The National Park Service and the U.S. Forest Service provided comments on the progress report.^[107] North Dakota documented this consultation in its 2015 Progress Report submittal.^[108]

IV. The EPA's Evaluation and Proposed Approval of North Dakota's NO X BART Determination for Coal Creek Station Units 1 and 2

The EPA is proposing to approve North Dakota's regional haze SIP submittal for the NO_X BART determination for Coal Creek Units 1 and 2. In our analysis of North Dakota's 2022 SIP submittal, we evaluated North Dakota's BART determination for Coal Creek Units 1 and 2 under CAA section 169A, 40 CFR 51.308(e)(1)(ii)(A), and 40 CFR part 51, appendix Y. Under these requirements, a State must consider the following five factors and include a ( print page 66023) demonstration of how they were taken into consideration in making a BART determination:

• costs of compliance;
• energy and non-air quality environmental impacts of compliance;
• existing pollution control equipment in use at the source;
• remaining useful life of any potentially affected sources; and
• visibility improvement anticipated to result from controls.

The State must consider these five factors in making BART determinations for a specific source.^[109] While States have discretion to consider these five factors, this discretion must be “reasonably exercised, and must be supported by adequate documentation of the analyses.” ^[110]

A. Basis of the EPA's Proposed Approval

The EPA is proposing to approve the portion of North Dakota's 2022 SIP submittal relating to the updated NO_X BART determination for Coal Creek Units 1 and 2, finding that LNC3+ at 0.15 lb/MMBtu (30-day rolling average) constitutes BART for these units. As an initial matter, we find that the State reasonably characterized the five factors required in a BART analysis, including the costs of compliance, energy and non-air quality environmental impacts of compliance, pollution control equipment at the source, the remaining useful life of any potentially affected sources, and visibility improvement anticipated to result from controls. The EPA also finds that North Dakota's revised cost calculation is appropriate, including: (1) the use of LNC3 with DryFining^TM as a baseline control technology in cost analysis; (2) the use of baseline NO_X emissions rates of 0.18 lb/MMBtu for both units based on three-year annual average data of LNC3 operation on Unit 1; (3) and the use of amortization periods of 20 and 30 years for SNCR and SCR, respectively. We find that the State reasonably considered that information, as well as each of the five BART factors, in reaching its revised NO_X BART determination. After consideration of all five of these factors, we propose to approve the State's determination that LNC3+ at a rate of 0.15lb/MMBtu (30-day rolling average) constitutes NO_X BART for Coal Creek Units 1 and 2.

1. Costs of Compliance

To evaluate North Dakota's updated BART analysis for Coal Creek Units 1 and 2 with respect to the cost of compliance, we first evaluate North Dakota's selection of baseline control technology and associated emission rates for analysis. Next, we evaluate North Dakota's characterization of the costs using the updated Control Cost Manual. Finally, we evaluate the reasonableness of the costs that North Dakota associated with the installation of LNC3+, LNC3+ w/SNCR, and LNC3+ w/SCR on Units 1 and 2 with respect to average and incremental cost-effectiveness, and the State's explanation for why requiring LNC3+ w/SNCR and LNC3+ w/SCR on Units 1 and 2 is unreasonable.

i. North Dakota's Selection of Baseline Emission Rates

Both Coal Creek Units 1 and 2 utilize “low NO_X coal-and-air nozzles with close-coupled and separated overfire air,” which is referred to as LNC3. Coal Creek installed additional NO_X controls (LNC3+) ^[111] on Unit 2 in 2010 and on Unit 1 in 2020. The 2016-2018 three-year annual average data from LNC3 (with DryFining^TM) on Unit 1 was used as the baseline performance rate in pounds of NO_X per MMBtu for both units. According to North Dakota, this approach is consistent with the EPA's responses to comments about anticipated controls at Coal Creek on the EPA's 2012 FIP for North Dakota, where the EPA stated that potential control options are evaluated “based on baseline conditions, not on ongoing revisions to a facility after the baseline period”, and that “It is not reasonable to consider controls installed after the baseline period in determining BART” because “Such an approach would tend to lead to higher cost effectiveness values for more effective controls and encourage sources to voluntarily install lesser controls to avoid installing more effective BART controls later”.^[112]

North Dakota further noted that because the annual average NO_X performance rate from 2002 through 2006 in lb/MMBtu for Units 1 and 2 was 0.22 and 0.23, respectively, the similarity of this five-year average supports the notion that Unit 1 and Unit 2 operate nearly identically with similar controls.^[113] According to North Dakota, the differences in performance rates between Unit 1 and Unit 2 since that time period can be attributed to the installation of LNC3+ on Unit 2 in 2010. The EPA finds that this information supports the use of a baseline rate of 0.18 lb/MMBtu for both Units 1 and 2 that is representative of historical operation at Unit 1. Though North Dakota did not incorporate all existing controls into the baseline, the State did consider the existing LNC3+ by performing an incremental cost analysis looking at the standalone cost of implementing SNCR, the next most stringent control, relative to the existing LNC3+. North Dakota also performed incremental analyses looking at the standalone cost of SCR relative to LNC3+. Per the EPA's BART guidelines, which advise that incremental costs should be calculated relative to the next most stringent control option,^[114] North Dakota also performed incremental cost analyses looking at the standalone cost of SCR relative to SNCR. Based on this information, the EPA finds that North Dakota selected an appropriate baseline rate and adequately considered the existing controls at Coal Creek in its cost analysis.

ii. North Dakota's Characterization of Costs Using the Control Cost Manual

The revised NO_X control cost estimates in the BART portion of North Dakota's 2022 SIP submittal are based on the current version of the EPA's Control Cost Manual, which has been revised since the first planning period. As updated, the Control Cost Manual includes a 30-year equipment life for SCR.^[115] The change in equipment life estimate from 20 to 30 years for SCR affects annual cost estimates, as well as average cost-effectiveness and incremental cost-effectiveness estimates. The Control Cost Manual also includes a 20-year equipment life for SNCR.^[116] We find North Dakota's use of the ( print page 66024) updated Control Cost Manual appropriate.

In its updated BART submission, North Dakota provided updated capital costs, annual costs, and average cost-effectiveness figures for LNC3+, LNC3+ w/SNCR, and LNC3+ w/SCR.^[117] In cost-effectiveness calculations, North Dakota used a 5.25% interest rate,^[118] which was the bank prime rate at the time the 2022 SIP submittal was in development (2018). North Dakota's use of the bank prime rate in control cost analyses follows the EPA's Control Cost Manual.^[119]

North Dakota also included incremental cost-effectiveness figures for LNC3+ w/SNCR and LNC3+ w/SCR.^[120] The BART Guidelines instruct that States can evaluate both average and incremental costs according to the Control Cost Manual to maintain and improve consistency.^[121] These figures take into account capital and annual costs and allow States and the EPA to compare costs of controls industry-wide. The BART Guidelines further caution against considering in isolation the capital costs of a control option, as large or small capital costs alone are not dispositive of the reasonableness of a potential control.^[122] Thus, we consider the average and incremental cost-effectiveness figures to be most relevant to our consideration of North Dakota's revised BART cost analysis.

iii. Costs Associated With the Installation of New Controls

In the revised cost analysis for the BART portion of the 2022 SIP submittal, North Dakota's cost estimates show an average cost-effectiveness for LNC3+ for Coal Creek Units 1 and 2 of $683/ton of NO_X removed.^[123] Based on North Dakota's estimates, the cost of LNC3+ is cost-effective.^[124] In our evaluation of North Dakota's 2013 SIP submittal, the EPA found an average value of $629/ton of NO_X removed based on LNC3+ installation at Antelope Valley Station Units 1 and 2 to be cost-effective, and we approved the State's NO_X BART determination for those sources in a final rule issued in 2022.^[125] Thus, the revised average cost-effectiveness value for LNC3+ on Coal Creek Units 1 and 2 in North Dakota's updated BART analysis is similar in cost to what North Dakota determined was cost-effective for a similar lignite coal facility in 2013. The EPA agrees with North Dakota that LNC3+ is cost effective for Coal Creek Units 1 and 2.

Next, North Dakota analyzed the cost-effectiveness of LNC3+ w/SNCR. North Dakota's cost estimates show an average cost-effectiveness for LNC3+ w/SNCR for Units 1 and 2 of $3,348/ton of NO_X removed.^[126] North Dakota's cost estimates also show an incremental cost-effectiveness for LNC3+ w/SNCR for Units 1 and 2 of $7,850 per ton of NO_X removed relative to the next-most-stringent control (LNC3+).^[127] North Dakota's decision to reject LNC3+ w/SNCR is based on its consideration of incremental cost. The EPA believes that both average and incremental costs provide information useful for making control determinations. The BART Guidelines explain how average and incremental costs may be used in an analysis to choose between two available control devices.^[128]

Though the average cost-effectiveness value that North Dakota evaluated for LNC3+ w/SNCR of $3,348/ton of NO_X removed is in line with average cost-effectiveness values that States and the EPA found reasonable in first planning period BART actions,^[129] and the visibility benefits of LNC3+ w/SNCR are not insignificant, we find that it was reasonable for North Dakota to determine that the relatively small incremental visibility benefits from adding SNCR (incremental visibility improvement ranging from 0.06-0.09 dv) ^[130] do not warrant selection of LCN3+ w/SNCR in light of the incremental cost of that control over LNC3+ ($7,850 per ton of NO_X removed). In a 2016 approval of a source-specific revision to the Arizona first planning period SIP that addressed BART requirements at Cholla Generating Station (Cholla), the EPA approved Arizona's determination that LNB+SOFA+SNCR was not required based on an incremental visibility improvement of 0.07 dv and an incremental cost of $6,989-7,091/ton compared to LNB+SOFA, the control Arizona selected for BART.^[131] The average cost associated with the addition of LNB+SOFA+SNCR was around $3,000-3,200/ton.^[132] The EPA explained:

With regard to SNCR, we find that it was reasonable for [Arizona] to conclude that the costs of SNCR were not warranted by the visibility benefits. In particular, with regard to costs, we are not aware of any instance in which the EPA has determined SNCR to be BART where the average cost-effectiveness of SNCR was greater than $3,000/ton and the incremental cost-effectiveness was roughly $7,000/ton, as is the case with Cholla Units 3 and 4. Similarly, we are not aware of any instance in which the EPA has disapproved a state's BART determination that rejected ( print page 66025) SNCR as BART based on similar cost-effectiveness values.^[133]

In its 2022 SIP revision, North Dakota finds the selection of LNC3+ w/SNCR to be unwarranted based on an average cost-effectiveness of $3,348/ton, an incremental cost-effectiveness of $7,850/ton, and incremental visibility improvement ranging from 0.06-0.09 dv compared to LNC3+ alone.^[134] These cost and visibility numbers are very similar to those evaluated in the EPA's 2016 action approving Arizona's BART determination that LNB+SOFA+SNCR was unwarranted at Cholla Units 3 and 4.

Thus, the EPA finds that it was reasonable for North Dakota to conclude that the incremental visibility benefits of LNC3+ w/SNCR over LNC3+ alone do not warrant selection of LNC3+ w/SNCR given its incremental cost over LNC3+.

Lastly, North Dakota analyzed the cost-effectiveness of LNC3+ w/SCR. North Dakota evaluated cost-effectiveness under two different control efficiencies: 0.08 lb/MMBtu NO_X and 0.06 lb/MMBtu NO_X removed. North Dakota's cost estimates show an average cost-effectiveness for Units 1 and 2 of $6,983/ton of NO_X removed (0.08 lb/MMBtu rate) and $6,284/ton of NO_X removed (0.06 lb/MMBtu rate).^[135] North Dakota's cost estimates show an incremental cost-effectiveness for LNC3+ w/SCR compared to LNC3+ for Units 1 and 2 of $13,368/ton of NO_X removed (0.08 lb/MMBtu rate) and $10,339/ton of NO_X removed (0.06 lb/MMBtu rate).^[136] North Dakota's cost estimates also show an incremental cost-effectiveness for LNC3+ w/SCR for Units 1 and 2 of $21,645/ton of NO_X removed (0.08 lb/MMBtu rate) and $12,206/ton of NO_X removed (0.06 lb/MMBtu rate), relative to the next-most-stringent control (LNC3+ w/SNCR).^[137] Because both the average and incremental costs in this instance are above the costs previously approved as cost-effective for BART,^[138] the EPA finds that North Dakota reasonably concluded, based on its analysis of average and incremental costs, that LNC3+ w/SCR is not cost-effective.

In summary, the EPA finds that North Dakota's consideration of costs of compliance is reasonable and consistent with the Control Cost Manual, the BART Guidelines, EPA guidance, and the EPA's reasoning in other first planning period BART actions. Specifically, the EPA finds that: (1) LNC3+ is a reasonable cost control based on the circumstances of this SIP submittal; (2) the incremental visibility benefits of LNC3+ w/SNCR over LNC3+ alone (incremental visibility improvement ranging from 0.06-0.09 dv) do not warrant selection of LNC3+ w/SCNR given its incremental cost compared to LNC3+ ($7,850 per ton of NO_X removed); and (3) the average and incremental cost-effectiveness values for installing LNC3+ w/SCR are not cost-effective. Based on inherent monthly variabilities in NO_X rate performance for LNC3+, including the likelihood of variability in rates due to changes in unit load to meet electricity needs, the EPA finds that North Dakota's proposed limit of 0.15 lb/MMBtu NO_X on a 30-day rolling average ^[139] for Coal Creek Units 1 and 2 is appropriate and provides for reasonable monthly variability.

2. Energy and Non-Air Quality Impacts of Compliance

North Dakota considered a variety of energy and non-air quality impacts. For SCR control technology, North Dakota noted visibility impacts from SAM emissions and additional energy use and emissions of pollutants associated with low dust SCR systems. For SNCR, North Dakota estimated that the control technology would require 70-80 million gallons of water per year,^[140] would result in an estimated 92,000 tons of fly ash disposal,^[141] and potentially produce pollution from ammonia slip.^[142] North Dakota supported its assessments with its own analysis and commissioned a study to evaluate the potential for adverse impacts of from ammoniated fly ash. North Dakota did not disqualify SCR or SNCR as reasonable control technologies based on the energy and non-air quality impacts of compliance.

North Dakota's consideration of energy and non-air quality impacts satisfies the BART Guidelines in that it provides some additional support for North Dakota's decision to reasonably rule out SCR and SNCR based on cost.

3. Pollution Control Equipment at the Source

As described in section III.C.3. and section IV.A.1.i. of this document, North Dakota's BART analysis in the 2022 SIP submittal considered existing controls on Coal Creek Units 1 and 2, including DryFining^TM and other combustion controls. Though North Dakota did not incorporate all existing controls into the baseline for its average cost-effectiveness analysis, the State did consider existing controls by performing an incremental cost-effectiveness analysis looking at the standalone cost of implementing SNCR, the next most stringent control, relative to the existing LNC3+ (which includes DryFining, a voluntarily installed control technology). North Dakota also performed incremental cost analyses looking at the standalone cost of SCR relative to the existing control of LNC3+. Per the EPA's BART Guidelines, which advise that incremental costs should be calculated relative to the next most stringent control option,^[143] North Dakota also performed incremental cost analyses looking at the standalone cost of SCR relative to SNCR.

North Dakota's approach of including voluntary existing controls in its evaluation of the BART factor “any existing pollution control technology in use at the source” is consistent with the Eighth Circuit's decision in North Dakota.^[144] The Eighth Circuit found that use of the word “any” has an expansive meaning and includes consideration of voluntarily installed controls as part of the BART factor “any existing pollution control technology in use at the source.” ^[145] Based on this, the EPA finds that North Dakota adequately considered any existing controls at Coal Creek in its BART determination.

4. Remaining Useful Life of Any Potentially Affected Sources

North Dakota's 2022 SIP submittal notes that Coal Creek is expected to operate beyond the life of the control equipment evaluated for BART. North Dakota considered remaining useful life as an element of its cost analysis and applied the timeframes of 30 years for ( print page 66026) SCR and 20 years for SNCR from the EPA's Control Cost Manual.^[146]

The BART Guidelines advise that States “may decide to treat the requirement to consider the source's `remaining useful life' of the source for BART determinations as one element of the overall cost analysis. The `remaining useful life' of a source, if it represents a relatively short time period, may affect the annualized costs of retrofit controls.” ^[147] The BART Guidelines further advise that if the remaining useful life of the source clearly exceeds the time period for amortization, “the remaining useful life has essentially no effect on control costs and on the BART determination process.” ^[148] If the remaining useful life of the source is less than the time period for amortizing the costs of the retrofit control, States may use the shorter time period in cost calculations.^[149]

Even though North Dakota expects Coal Creek to operate beyond the life of the control equipment, the State chose to apply in its cost analyses the shorter timeframes of 30 years for SCR and 20 years for SNCR recommended in the EPA's Control Cost Manual.^[150] For this reason, the EPA finds that North Dakota satisfactorily considered this factor.

5. Visibility Improvement Anticipated To Result From Controls

North Dakota considered CALPUFF dispersion modeling conducted by Coal Creek to assess the potential visibility improvement from the use of additional NO_X BART controls. The EPA's BART Guidelines advise that for the purposes of assessing the degree of improvement in visibility from various BART control levels for a BART determination, States may use CALPUFF modeling using source-specific and site-specific data.^[151] The BART Guidelines further advise that if expected improvement is shown from the various control choices, the State can weigh the results with the other four BART determination factors when establishing BART for a particular source.^[152]

Table 2 in section III.C.5. of this document displays North Dakota's modeled average combined 98th percentile deciview improvement from 2000-2002 for Coal Creek Station Unit 1 and Unit 2. The modeling indicates that in general, there is an incremental improvement in deciview reductions for each increasingly stringent control technology option. For LNC3+ w/SNCR, the largest modeled deciview improvement (compared to Modeling Scenario 1) for Theodore Roosevelt National Park was 0.21, and for Lostwood was 0.21, with incremental visibility improvement from the addition of SNCR ranging from 0.06-0.09 dv (compared to LNC3+ alone). As noted in section IV.A.1.iii. of this document, the EPA finds that the incremental visibility benefits of LNC3+ w/SNCR over LNC3+ alone do not warrant selection of LNC3+ w/SNCR given its incremental cost compared to LNC3+. For LNC3+ w/SCR 5% SO₂ to SO₃ oxidation rate, the largest modeled deciview improvement for Theodore Roosevelt National Park was 0.14 compared to the Modeling Scenario 1. Notably, for LNC3+ w/SCR 5% SO₂ to SO₃ oxidation rate, the modeling indicated a decrease in deciview improvement for Lostwood at −0.02 deciviews compared to the Modeling Scenario 1. North Dakota's assessment of the modeling data was that none of the NO_X BART controls were shown to have a significant impact on improving visibility in North Dakota's Class I areas. Considering the modeled overall and incremental visibility improvements (visibility improvement between two contr ol measures) associated with installation of LNC3+ w/SCR versus LNC3+ alone (maximum incremental improvement of 0.21 dv) ^[153] and LNC3+ w/SCR versus LNC3+ w/SNCR (maximum incremental improvement of 0.12 dv) ^[154] and in light of the incremental costs described in section IV.A.1. of this document, the EPA agrees that LNC3+ w/SCR is not warranted.

Because North Dakota conducted the modeling in accordance with the BART Guidelines and reasonably concluded that the difference in visibility improvements between installing LNC3+ versus LNC3+ w/SCR were relatively small, the EPA finds that North Dakota's consideration of visibility improvement was satisfactory.

6. Summary of the EPA's Evaluation of North Dakota's NO_X BART Determination for Coal Creek Station Units 1 and 2

In summary, the EPA proposes to approve the portion of North Dakota's 2022 SIP submittal that addresses North Dakota's NO_X BART determination for Coal Creek Units 1 and 2. The EPA bases this decision on the determination that North Dakota reasonably considered all five factors in determining BART as required under CAA section 169A, 40 CFR 51.308(e), and 40 CFR part 51, appendix Y. This action addresses the last outstanding North Dakota BART requirement for the first planning period.

B. Clean Air Act Section 110(l)

Under CAA section 110(l), the EPA cannot approve a plan revision “if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress (as defined in section 7501 of this title), or any other applicable requirement of this chapter.” All areas in North Dakota are currently meeting the NAAQS.^[155] This proposed approval would require new NO_X BART limits at Coal Creek Units 1 and 2, resulting in a reduction of 1,162 tpy of NO_X from the baseline. Because this action is associated with a reduction in NO_X emissions and is not associated with any increase in emissions, this action is unlikely to interfere with attainment or reasonable further progress in North Dakota or nearby States.

The EPA finds that approval of the portion of North Dakota's August 2022 SIP submittal that addresses NO_X BART for Coal Creek is in compliance with CAA section 110(l).

C. Coordination With FLMs

Under 40 CFR 51.308(i)(2), States are obligated to provide FLMs with an opportunity for consultation in development of the State's proposed SIP submittal no less than sixty days prior to the associated public hearing or public comment opportunity.

For the 2022 SIP submittal, North Dakota engaged with FLMs early in the planning process by participating in WRAP meetings and by holding separate calls with FLMs to discuss visibility impairment in Class I areas and the State's plans for the North Dakota 2022 SIP submittal. North Dakota also met via video conference with the NPS on November 6, 2020, and December 15, 2020, and with the USFS on November 23, 2020.

Upon completing its draft 2022 SIP submittal, North Dakota provided the draft to FLMs for a review and consultation period from September 20, 2021, through November 19, 2021, pursuant to 40 CFR 51.308(i)(2). ( print page 66027) Additionally, North Dakota held a video conference with the NPS, USFS, and EPA Region 8 staff on November 10, 2021, to discuss the draft and receive feedback from the FLMs. North Dakota received comments from USFS on November 17, 2021, and from the NPS on November 19, 2021.¹³⁹ Specific to the BART determination for Coal Creek Units 1 and 2 contained in North Dakota's 2022 SIP submittal, the NPS commented on the control efficiency considered by North Dakota for SCR controls, the 5.25% interest rate used by North Dakota in cost-effectiveness calculations, and the remaining useful life used by North Dakota in cost calculations. North Dakota responded to the FLM comments and included the responses in appendix D of the North Dakota 2022 SIP submittal, in accordance with 40 CFR 51.308(i)(3).

In consideration of these consultation actions, the EPA finds that North Dakota has satisfied the requirements under 40 CFR 51.308(i) to consult with the FLMs for the 2022 SIP submittal as it pertains to Coal Creek Station Units 1 and 2 BART.

V. The EPA's Evaluation of North Dakota's Five-Year Progress Report

This section includes the EPA's analysis of North Dakota's 2015 Progress Report for the first planning period and an explanation of the basis of our proposed approval. As listed in section III.D. above, North Dakota's 2015 Progress Report included the elements required in 40 CFR 51.308(g) and 40 CFR 51.308(h) of the 1999 Regional Haze Rule, which was the applicable rule at the time of submission,^[156] As a result, the EPA finds that North Dakota's progress report addresses the requirements of the CAA and the EPA's rules that require States to submit periodic reports describing progress toward reasonable progress goals established for regional haze.

To meet 40 CFR 51.308(g)(1), North Dakota included a description of the status of implementation of the measures included in the first planning period implementation plan, including current emissions rates, BART/reasonable progress limits, and implementation dates.^[157] North Dakota also included a breakdown of its species contribution to impairment in both in-state and out-of-state Class I areas.^[158] To address 40 CFR 51.308(g)(2), North Dakota included a list of emissions reductions that have occurred as a result of Regional Haze SIP control requirements.^[159]

To satisfy 40 CFR 51.308(g)(3), North Dakota included an assessment of visibility conditions and changes on least-impaired days and most-impaired days for both Class I areas within the State (Lostwood Wilderness Area and Theodore Roosevelt National Park) expressed in terms of 5-year averages of these annual values.^[160] North Dakota compared the baseline average of visibility impairment to both an average from 2005-2009 and an average from 2008-2012.^[161]

To meet 40 CFR 51.308(g)(4), North Dakota included an analysis tracking the change over the past 5 years addressed within the 2015 progress report in emissions of pollutants contributing to visibility impairment from all sources and activities within the State; these numbers are also broken down by source category.^[162] Here, North Dakota included 2011 data from the most recent triennial reporting requirements as of the time of progress report development.^[163]

To satisfy 40 CFR 51.308(g)(5), North Dakota included an assessment of changes in anthropogenic emissions within or outside of the State that have occurred over the past 5 years addressed within the 2015 progress report.^[164] Considering changes in emissions over time and expected reductions in NO_X and VOC emissions due to a reduction in flaring, North Dakota concluded that there was no evidence at the time that the increase in oil and gas activity (or any other sector) in North Dakota was impeding progress towards the visibility goal.^[165]

To meet 40 CFR 51.308(g)(6), North Dakota included an assessment of the implementation plan elements that were current at the time of submission (including BART controls and reasonable progress controls resulting from the first planning period)..^[166] North Dakota ultimately concluded that its emissions would not impede the achievement of reasonable progress goals in in-state or out-of-state Class I areas.^[167]

North Dakota also included an assessment of its visibility monitoring strategy to address 40 CFR 51.308(g)(7). North Dakota stated that it relies on the IMPROVE ^[168] program for its monitoring strategy.^[169] North Dakota confirmed that there is no change needed to this monitoring strategy at this time.^[170] . North Dakota met the requirements of 40 CFR 51.308(h) by including a determination that the existing implementation plan is sufficient to achieve established goals for visibility improvement and emissions reduction.^[171]

North Dakota provided an opportunity for consultation with FLMs for the 2015 progress report by providing a copy of the draft progress report on June 25, 2014. The 2015 progress report was distributed to the National Park Service, the U.S. Fish and Wildlife Service, the U.S. Forest Service, and EPA Region 8 staff. The National Park Service, the U.S. Forest Service, and the EPA provided comments.^[172] North Dakota documented this consultation in its 2015 progress report submittal.^[173] The EPA finds that North Dakota has satisfied the requirement to consult with FLMs on the 2015 progress report.

Based on the information provided in North Dakota's 2015 progress report, the EPA proposes to approve North Dakota's 2015 progress report for the first planning period.

VI. Summary of the EPA's Proposed Action

The EPA is proposing to approve North Dakota's NO_X BART determination for Coal Creek units 1 and 2 from the August 2022 SIP submittal. Specifically, the EPA is proposing to approve the NO_X BART determination for the Coal Creek Station, included in appendix F of North Dakota's 2022 SIP submittal, of ( print page 66028) 0.15 lb/MMBtu NO_X averaged across unit 1 and unit 2 on a 30-day rolling average. Additionally, the EPA is proposing to approve North Dakota's 2015 Progress Report as meeting the requirements of 40 CFR 51.308(g) and (h).

VII. Environmental Justice

The EPA conducted an environmental justice (EJ) screening analysis around the location of Coal Creek to identify potential environmental stressors on the nearby communities. The EPA is providing the information associated with this analysis for informational purposes only; it does not form any part of the basis of this proposed action.

The EPA conducted the screening analysis using EJScreen, an EJ mapping and screening tool that provides the EPA with a nationally consistent dataset and approach for combining various environmental and demographic indicators.^[174] The EPA prepared an EJScreen report covering buffer areas of approximately six miles around Coal Creek. From this report, there were no EJ indices greater than the 80th national percentiles.^[175] The full, detailed EJScreen report is provided in the docket for this rulemaking.

VIII. Incorporation by Reference

In this proposed rule, the EPA is proposing to include regulatory text in an EPA final rule that includes incorporation by reference. In accordance with the requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference the SIP amendments described in section VI. The EPA has made, and will continue to make, these materials generally available through https://www.regulations.gov (refer to docket EPA-R08-OAR-2023-0641).

IX. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this action merely proposes to approve State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have Federalism implications as specified inExecutive Order 13132 (64 FR 43255, August 10, 1999);
• Is not an economically significant regulatory action based on health or safety risks subject toExecutive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action subject toExecutive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the proposed rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Executive Order 12898 (Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations, 59 FR 7629, Feb. 16, 1994) directs Federal agencies to identify and address “disproportionately high and adverse human health or environmental effects” of their actions on minority populations and low-income populations to the greatest extent practicable and permitted by law. The EPA defines environmental justice (EJ) as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.” The EPA further defines the term fair treatment to mean that “no group of people should bear a disproportionate burden of environmental harms and risks, including those resulting from the negative environmental consequences of industrial, governmental, and commercial operations or programs and policies.”

North Dakota did not evaluate environmental justice considerations as part of its SIP submittal; the CAA and applicable implementing regulations neither prohibit nor require such an evaluation. The EPA performed an environmental justice screening analysis, as described above in section VI. The analysis was done for the purpose of providing additional context and information about this rulemaking to the public, not as a basis of the action. There is no information in the record upon which this decision is based inconsistent with the stated goal of E.O. 12898 of achieving environmental justice for people of color, low-income populations, and Indigenous peoples.

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Carbon monoxide
• Greenhouse gases
• Incorporation by reference
• Intergovernmental relations
• Lead
• Nitrogen dioxide
• Ozone
• Particulate matter
• Reporting and recordkeeping requirements
• Sulfur oxides
• Volatile organic compounds

(Authority: 42 U.S.C. 7401 et seq.)

Dated: August 2, 2024.

KC Becker,

Regional Administrator, Region 8.

For the reasons set forth in the preamble, 40 CFR part 52 is proposed to be amended as follows:

PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

1. The authority citation for part 52 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

Subpart JJ—North Dakota

2. In § 52.1820, the table in paragraph (d) is amended by revising the entry “PTC10005” under the center heading “Coal Creek Station Units 1 and 2.” to read as follows:

§ 52.1820

Identification of plan.

* * * * *

(d) * * * ( print page 66029)

Rule No.	Rule title	State effective date	EPA effective date	Final rule citation/date	Comments
*         *         *         *         *         *         *
Coal Creek Station Units 1 and 2.
PTC 21001	Air Pollution Control Permit to Construct for Best Available Retrofit Technology (BART)	7/27/2022	[Date 30 days after date of publication of the final rule in the Federal Register ]	[ Federal Register citation of the final rule], [Date of publication of the final rule in the Federal Register ]	Only: NO X BART emissions limits for Units 1 and 2 and corresponding monitoring, recordkeeping, and reporting requirements.
*         *         *         *         *         *         *