The U.S. Environmental Protection Agency (EPA) has partially approved a revision to the North Dakota State Implementation Plan (SIP) addressing regional haze, but did have to back off on one part of its own plan due to a December 2011 court decision.
The SIP revisions proposed by the state were submitted to address the requirements of the Clean Air Act (CAA or Act) and EPA rules that require states to prevent any future and remedy any existing man-made impairment of visibility in mandatory Class I areas. EPA said in an April 6 Federal Register notice that it promulgated a Federal Implementation Plan (FIP) to address the gaps in the state plan resulting from EPA’s partial disapproval of North Dakota’s Regional Haze (RH) SIP.
In addition, EPA disapproved a revision to the North Dakota SIP addressing the interstate transport of pollutants that the governor submitted in April 6 2009. EPA rejected it because it does not meet the Act’s requirements concerning noninterference with programs to protect visibility in other states. To address this deficiency, EPA promulgated a FIP.
EPA made several changes in the proposed SIP approval/disapproval it issued some time ago, and the final SIP approval/disapproval published April 6. In its proposed disapproval for the state SIP revisions, EPA had rejected:
- North Dakota’s NOx best available retrofit technology (BART) determinations and emissions limits for Milton R. Young Station (MRYS) Units 1 and 2, Leland Olds Station (LOS) Unit 2, and Coal Creek Station (CCS) Units 1 and 2. Milton R. Young is a Minnkota Power Cooperative plant, Leland Olds is a Basin Electric Power Cooperative plant and Coal Creek is controlled by Great River Energy.
- North Dakota’s determination under the reasonable progress requirements that no additional NOx emissions controls were warranted at Antelope Valley Station (AVS) Units 1 and 2. Antelope Valley is a Basin Electric plant.
- North Dakota’s reasonable progress goals (RPGs).
- Portions of North Dakota’s long-term strategy (LTS) that relied on or reflected other aspects of the RH SIP that EPA was proposing to disapprove.
EPA had proposed to approve the remaining aspects of two of North Dakota’s RH SIP revisions. EPA also proposed to promulgate a FIP to address the deficiencies in the North Dakota RH SIP that it identified in its proposal. The proposed FIP included the following elements:
- NOx BART determinations and emission limits for MRYS Units 1 and 2 and Leland Olds Station Unit 2.
- NOx BART determination and emission limit for CCS Units 1 and 2.
- A reasonable progress determination and NOx emission limit for AVS Units 1 and 2.
- A five-year deadline to meet the emission limits and monitoring, recordkeeping, and reporting requirements for the above seven units to ensure compliance.
- RPGs consistent with the SIP limits proposed for approval and proposed FIP limits.
- LTS elements that would reflect the other aspects of the proposed FIP.
EPA works out interstate transport issues
EPA had proposed to disapprove the portion of North Dakota’s April 2009 SIP revision for interstate transport in which North Dakota intended to address a requirement that emissions from North Dakota sources not interfere with measures required in the SIP of any other state under part C of the CAA to protect visibility.
Because of this proposed disapproval, EPA proposed a FIP to meet the visibility protection requirement. To meet this FIP duty, EPA proposed to find that North Dakota sources would be sufficiently controlled to eliminate interference with the visibility programs of other states by a combination of the measures that EPA was proposing to approve as meeting the regional haze SIP requirements combined with the additional measures that it was proposing to impose in a FIP to meet the remaining regional haze SIP requirements.
EPA requested comments on all aspects of its proposed action and provided a two-month comment period that closed in November 2011. EPA received a significant number of comments, both from commenters, particularly citizens and environmental groups, that supported EPA’s proposed action, and from commenters, primarily from state and city agencies, rural power cooperatives, and industrial facilities and groups, that were critical of the proposed action.
In the final action published April 6, EPA disapproved:
- North Dakota’s NOx BART determinations and emissions limits for CCS Units 1 and 2.
- North Dakota’s determination under the reasonable progress requirements that no additional NOx emissions controls are warranted at AVS Units 1 and 2.
- North Dakota’s RPGs.
- Portions of North Dakota’s LTS that rely on or reflect other aspects of the RH SIP that EPA has now disapproved.
EPA did approve the remaining aspects of North Dakota’s RH SIP revision that was submitted in March 2010 and SIP Supplement No. 1 submitted in July 2010. EPA said it is not taking action on the remainder of a July 2011 state submittal at this time.
The final FIP that EPA has issued to fill in the gaps on what it has disapproved includes the following elements:
- NOx BART determination and emission limit for CCS Units 1 and 2 of 0.13 lb/MMBtu averaged across the two units on a 30-day rolling average, and a requirement that the owners/operators comply with this NOx BART limit within five years of the effective date of this final rule.
- A reasonable progress determination and NOx emission limit for AVS Units 1 and 2 of 0.17 lb/MMBtu that applies singly to each of these units on a 30-day rolling average, and a requirement that the owner/operator meet the limit as expeditiously as practicable, but no later than July 31, 2018.
- Monitoring, record-keeping, and reporting requirements for the above four units to ensure compliance with these emission limitations.
- RPGs consistent with the SIP limits approved and the final FIP limits.
- LTS elements that reflect the other aspects of the finalized FIP.
As for the FIP that the agency came up with to address the “good neighbor” pollution transport impacts on nearby states, EPA found that North Dakota sources will be sufficiently controlled to eliminate interference with the visibility programs of other states by a combination of the measures in the North Dakota SIP that it did approve, plus the measures in the FIP. “We note that North Dakota always has the discretion to revise its SIP and submit the revision to us,” EPA wrote. “Should such a revision meet CAA requirements, we would replace our FIP with North Dakota’s SIP revision.”
EPA explained the reasons for the SIP changes that it included in its own FIP.
NOx BART for Milton R. Young Station Units 1-2 and Leland Olds Station Unit 2 – After considering a recent judicial decision, EPA decided to approve North Dakota’s NOx BART determination for MRYS 1 and 2 and LOS 2 and to not promulgate a FIP for NOx BART for these units. In July 2006, the U.S. District Court for the District of North Dakota entered a consent decree between EPA, the state, and Minnkota Power Cooperative related to permitting requirements at MRYS 1 and 2. The consent decree called for North Dakota to make a best available control technology (BACT) determination for NOx for MRYS 1 and 2.
In November 2010, North Dakota determined BACT for NOx to be limits of 0.36 lb/MMBtu for MRYS 1 and 0.35 lb/MMBtu for MRYS 2 based on the use of selective non-catalytic reduction (SNCR) technology. North Dakota eliminated selective catalytic reduction (SCR), a higher performing technology, based on a finding that SCR was not technically feasible to control emissions from North Dakota lignite coal. EPA disagreed with North Dakota’s findings and the selection of SNCR as BACT and initiated the dispute resolution process under the consent decree. In December 2011, the court determined that EPA had not demonstrated that North Dakota’s findings were unreasonable. The court decided that North Dakota, based on the administrative record for its BACT determination, had a reasonable basis for concluding that SCR is not technically feasible for treating North Dakota lignite at MRYS.
In light of the court’s decision, EPA concluded that it would be inappropriate to proceed with its proposed disapproval of SNCR as BART and its proposed FIP to impose SCR at MRYS 1 and 2 and LOS 2. While LOS 2 was not the subject of the BACT determination, the same reasoning that applies to MRYS 1 and 2 also applies to LOS 2. It is the same type of boiler, also burning North Dakota lignite.
“Thus, with this action we are approving North Dakota’s NOx BART determinations for MRYS 1 and 2 and LOS 2, and no FIP for these units is necessary,” EPA stated. “The applicable limits are 0.36 lb/MMBtu for MRYS 1 and 0.35 lb/MMBtu for MRYS 2 and 0.35 lb/MMBtu for LOS 2. We note, however, that the state has indicated a willingness to pursue the conduct of a pilot study at MRYS and/or LOS to analyze the expected replacement rate of SCR catalyst exposed to flue gas from the combustion of North Dakota lignite at these cyclone units in a low-dust or tail-end configuration. It is our expectation that the results of such a study could be used to inform further evaluation of SCR as a potential control technology when the state evaluates reasonable progress in the next planning period for regional haze.”
NOx BART for Coal Creek Station (CCS) Units 1-2 – EPA proposed a NOx BART FIP limit for CCS 1 and 2 of 0.12 lb/MMBtu that would apply to each unit individually on a 30-day rolling average basis. It based this limit on its proposed finding that SNCR plus separated overfire air (SOFA) plus low NOx burners (LNB) was the best available retrofit technology. “While we continue to find that SNCR plus SOFA plus LNB is the best available retrofit technology, we are changing the emission limit to 0.13 lb/MMBtu averaged over both units on a 30-day rolling average basis,” EPA noted. “Evidence submitted by commenters and our own additional research in evaluating comments has led us to conclude that this represents a more reasonable limit to apply on a 30-day rolling average basis. This limit represents a control efficiency of 48% based on the average annual baseline emission rate of 0.22 lb/MMBtu (2003–2004) provided in the state’s BART determination.”