EPA agrees to rule on new SO2 emissions limits for Sherburne County coal plant

The U.S. Environmental Protection Agency said in a notice to be published in the June 1 Federal Register that it has agreed, in order to settle a lawsuit filed by several environmental groups, to rule on a petition related to regional haze impacts of the coal-fired Sherburne County power plant in Minnesota.

In accordance with section 113(g) of the Clean Air Act, EPA is giving notice of a proposed settlement agreement to address a lawsuit filed by the National Parks Conservation Association, Minnesota Center for Environmental Advocacy, Friends of the Boundary Waters, Voyageurs National Park Association, Fresh Energy and the Sierra Club. An intervenor in the case is plant operator Northern States Power Minnesota d/b/a Xcel Energy. The lawsuit was filed in 2012 in the U.S. District Court for the District of Minnesota.

The complaint alleges that the Administrator of EPA failed to perform a mandatory duty to respond to a 2009 letter by the Department of the Interior (DOI) certifying that visibility impairment in Minnesota’s Voyageurs National Park and Michigan’s Isle Royale National Park is reasonably attributable to emissions from the Sherburne County (Sherco) plant. The proposed settlement agreement establishes a deadline for EPA to take final action to revise the Minnesota Reasonably Attributable Visibility Impairment (RAVI) Federal Implementation Plan (FIP).

Written comments on the proposed settlement agreement must be received within 30 days after the June 1 publication in the Federal Register.

In October 2009, DOI provided a letter to EPA in which DOI stated “that there exists reasonably attributable impairment of visibility at Voyageurs and Isle Royale due to emissions from the Sherco facility.” In December 2012, plaintiffs filed their complaint in this litigation alleging that, since receiving DOI’s letter, the Administrator had failed to perform a mandatory duty to promulgate a federal RAVI best available retrofit technology (BART) determination for Sherco. In response to the lawsuit, EPA filed an answer in February 2013 denying that the Administrator has a mandatory duty to promulgate RAVI BART for Sherco because EPA has not determined that visibility impairment at one or more Class I areas is reasonably attributable to emissions from Sherco.

On March 25 of this year, plaintiffs filed an amended complaint, alleging that the Administrator had failed to perform a mandatory duty “to identify and analyze for BART each existing stationary facility which may reasonably be anticipated to cause or contribute to impairment of visibility in any mandatory Class I Federal area where the impairment in the mandatory Class I Federal area is reasonably attributable to that existing stationary facility.”

The proposed settlement would resolve the lawsuit by establishing that EPA will propose to revise the Minnesota RAVI FIP to include specific SO2 emission limitations for Sherco Units 1, 2, and 3, and take final action on the proposal within seven months of the effective date of the settlement agreement. The proposed settlement agreement also provides that nothing in the agreement shall be construed to limit or modify any discretion afforded EPA by the Clean Air Act or by general principles of administrative law in taking those actions.

The 2,222-MW Sherco plant is located at Becker, Minn., 45 miles northwest of the Twin Cities, on the Mississippi River. Unit 3 is 41% owned by the Southern Minnesota Municipal Power Agency. Unit 3 already employs a dry scrubber system, which uses a mist of lime slurry in spray dryers to trap SO2. Units 1 and 2 have wet scrubbers, which use an alkaline spray to capture SO2 and ash.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.