Utah’s Regional Haze State Implementation Plan (SIP) was developed to protect the vistas of Class 1 areas, including Utah’s five national parks, from regional haze. In 2013, EPA approved the majority of the Regional Haze SIP dealing with emission reductions for sulfur dioxide (SO2) but disapproved the SIP’s best available retrofit technology (BART) determinations for nitrogen oxides (NOx) and particulate matter (PM) for Units 1 and 2 at PacifiCorp’s Hunter and Huntington plants.
Working closely with EPA, DAQ revised the Regional Haze SIP to demonstrate that an alternative to BART for nitrogen oxides (NOx) would achieve greater reasonable progress than BART. Combined emissions of NOx, SO2, and PM in the Alternative to BART Regional Haze SIP would be lower than achieved by the most stringent technology available to reduce NOx from sources subject to BART. Visibility modeling showed that the alternative would provide visibility improvement on a greater number of days and greater average improvement with reductions achieved earlier than required by rule.
On June 1, 2016, the EPA issued a partial approval, partial disapproval (541.56 KB) of Utah’s regional haze plan. The decision included a Federal Implementation Plan (FIP) requiring installation of selective catalytic reduction (SCR) (27.53 KB) equipment at PacifiCorp’s Hunter and Huntington plants to further reduce NOx emissions. DAQ filed an appeal of the EPA’s decision in the Tenth Circuit Court and applied for an administrative stay of implementation of the decision, stating that the costly $700 million in upgrades will have imperceptible benefits to air quality in the region.
In July 2017, EPA Administrator Pruitt sent a letter to Governor Gary Herbert stating that the agency intended to reconsider its previous decision on the 2015 Regional Haze SIP. According to the EPA, this reconsideration was based on new evidence not available at the time of the 2016 decision, including data from additional visibility modeling, the seasonality of visibility improvements relative to visitation at the Class I areas affected by the Utah coal plants, and the timing of emission reductions.
In September 2017, the U.S. 10th Circuit Court of Appeals granted a stay to prevent the EPA’s final order from taking effect. DAQ and EPA have committed to work together to find common-sense solutions for achieving reasonable progress towards reducing regional haze.