The U.S. Environmental Protection Agency will publish in the Feb. 18 Federal Register a final decision on reconsideration that grants a break under the regional haze program to coal-fired capacity in North Dakota.
In April 2012, EPA published a final rule partially approving and partially disapproving a North Dakota State Implementation Plan (SIP) addressing regional haze submitted by the governor of North Dakota. The EPA administrator subsequently received a petition requesting EPA to reconsider its approval of certain elements of North Dakota’s regional haze SIP. Specifically, the petition raised several objections to EPA’s approval of the state’s best available retrofit technology (BART) emission limits for NOx for the coal-fired Milton R. Young Station (MRYS) Units 1 and 2 and Leland Olds Station (LOS) Unit 2.
In March 2013, EPA announced its decision to reconsider its approval of the state’s NOx BART limits for these facilities. In the same action, EPA proposed to affirm its prior approval of these elements of North Dakota’s SIP. As a result of this reconsideration process, EPA has concluded that no changes are warranted to its 2012 approval of the NOx BART limits for these units.
The petitions for reconsideration were from North Dakota, Great River Energy (the owner of Coal Creek Station), and Earthjustice on behalf of other environmental groups. Parallel lawsuits were also filed by these parties.
EPA noted that “we consider it appropriate to approve the State’s selection of selective non-catalytic reduction (SNCR) plus advanced separated overfire air (ASOFA) controls as BART at MRYS Units 1 and 2 and LOS Unit 2. As we noted in our proposal, evaluations of technical feasibility often change over time. In the future, North Dakota may reach a different conclusion about the technical feasibility of selective catalytic reduction (SCR) controls at these plants as part of, for example, a reasonable progress analysis. The regional haze program requires additional reasonable progress reviews every ten years to ensure that states make progress toward the visibility goal of the [Clean Air Act]. Therefore, we expect that North Dakota will reassess the technical feasibility of SCR controls at these plants as part of a future reasonable progress analysis.”
SNCR is much less costly than SCR, with a major issue in this matter being the technical feasibility of SCR on lignite-fired boilers. EPA said on that point: “Regardless of EPA’s position on the technical feasibility of SCR for MRYS Units 1 and 2 and LOS Unit 2, we acknowledge that throughout the development of the BACT and BART determinations for these units, other parties contested the feasibility of SCR on these high-temperature cyclone boiler units burning high-sodium North Dakota lignite. The State gave great weight to the fact that it did not receive any catalyst vendor guarantees.”