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Section 169 of the Clean Air Act was enacted to establish a national visibility protection goal. It calls for the U.S. Environmental Protection Agency (EPA) to establish rules to ensure reasonable progress toward meeting this national goal. It gives states the primary authority to implement the visibility protection requirements through state implementation plans (SIP). The EPA’s role is to provide oversight and assume authority if a state’s plan is inadequate. The goal of regional haze regulation is to improve visibility in Class I areas, such as national parks and wilderness areas. It is not a health-based requirement.
In February 2010, the North Dakota Department of Health (NDDH) adopted its SIP wherein it determined the best available retrofit technology (BART) emission limits for affected North Dakota sources including Coal Creek Station. On March 2, 2012, EPA published its disapproval of the SIP and its overriding federal implementation plan (FIP) which included a more stringent requirement than the SIP for emissions of nitrogen oxides (NOx) from Coal Creek Station. In September 2013, the U.S. Court of Appeals for the Eighth Circuit ruled that EPA’s FIP was arbitrary and capricious. As a result of the court’s ruling, EPA must either affirm the revised SIP or propose a new FIP. To date, EPA has not taken action.
In its revised SIP, North Dakota determined the necessary NOx reductions would be achieved at Coal Creek Station as a result of Great River Energy’s DryFiningTM system and the installation of further traditional controls. After investing in the first-of-its-kind technology, Great River Energy has seen significant reductions across the spectrum of emissions including 40 percent for sulfur dioxide and 20 percent for NOx at the plant.
North Dakota’s SIP was crafted after years of careful consideration of the statutory factors and a thorough technical review, while taking into account public comments. As a result of DryFining, NOx emissions from Coal Creek Station have already been significantly reduced. Great River Energy is on target to meet the requirements of the revised SIP within its required timeframe.
December 15, 2016