The U.S. Environmental Protection Agency, in a Feb. 16 letter to the state of Kentucky, said that due to uncertainty about SO2 emissions from the coal-fired, 417-MW Wilson plant of Big Rivers Electric Corp. and about the future retirement dates for two units at the Tennessee Valley Authority‘s Paradise coal plant, it can’t designate an area in western Kentucky as being in attainment with the SO2 NAAQS.
Under section 107(d) of the Clean Air Act, EPA must designate areas as either “unclassifiable,” “attainment,” or “nonattainment” for the 2010 one-hour sulfur dioxide (SO2) primary national ambient air quality standard (NAAQS). The CAA defines a nonattainment area as one that does not meet the NAAQS or that contributes to a violation in a nearby area. An attainment area is any area other than a nonattainment area that meets the NAAQS. Unclassifiable areas are defined as those that cannot be classified on the basis of available information as meeting or not meeting the NAAQS.
The Commonwealth of Kentucky submitted updated recommendations to EPA in September 2015, ahead of a July 2, 2016, deadline for the EPA to designate certain areas. This deadline is the first of three deadlines established by the U.S. District Court for the Northern District of California, as a result of a lawsuit by environmental groups, for the EPA to complete area designations for the 2010 SO2 NAAQS. EPA on Feb. 16 sent letters to various states, including Kentucky, about preliminary decisions ahead of that July 2 deadline.
The Ohio County, Kentucky, area contains a stationary source that according to the EPA’s Air Markets Database emitted in 2012 either more than 16,000 tons of SO2 or more than 2,600 tons of SO2 and had an annual average emission rate of at least 0.45 lbs SO2/mmBTU. As of March 2, 2015, this stationary source had not met the specific requirements for being “announced for retirement,” which would exclude it from this process.
Specifically, in 2012, the D.B. Wilson Power Plant emitted 7,387 tons of SO2, and had an emissions rate of 0.45 lbs SO2/mmBTU. Pursuant to the March 2, 2015 court-ordered schedule, the EPA must designate the area surrounding the facility by July 2, 2016.
In its submission, Kentucky recommended that the area surrounding Plant Wilson, which is the entirety of Ohio County, be designated as attainment. The state’s assessment and characterization were performed using air dispersion modeling software, i.e., AERMOD, analyzing allowable emissions. This work was originally conducted by Trinity Consultants and prepared for the Big Rivers Electric. The state then reviewed and submitted the information to the EPA.
“After careful review of the Commonwealth’s assessment, supporting documentation, and all available data, the EPA intends to designate Ohio County in its entirety as unclassifiable because the EPA does not have necessary information at this time to determine the attainment status of the Ohio County Area,” said EPA. “Specifically, the future allowable emission limit for Plant Wilson used to model attainment for the Ohio County Area has not been established as federally-enforceable by the Commonwealth. In order for the EPA to consider the future allowable emission limit of 0.85 lbs SO2/mmBTU for Plant Wilson for the designations to be finalized no later than July 2, 2016, the Commonwealth will have to ensure that these limits are federally-enforceable (and the EPA has confirmed such) by the time this round of designations is complete.”
EPA says precise timing of Paradise coal retirements an open issue
Also, EPA said it needs additional information regarding the operating status of Units 1 and 2 at the Tennessee Valley Authority’s coal-fired Paradise Fossil Plant in Muhlenberg County, Ky., to determine if Units 1 and 2 are shut down for the purposes of this evaluation. TVA has announced plans to retire Units 1 and 2 at Paradise, replacing them with new gas-fired generation at the site, and to keep the coal-fired Unit 3 in operation. If these two units are not shut, additional explanation would be necessary as to why these emissions were not included in the modeling for this area.
The Paradise plant is approximately 22 kilometers southeast of Plant Wilson, and had SO2 emissions of 19,654.55 tons in 2014. Units 1 and 2 at the facility are scheduled to shut down by June 2017, according to an annual report developed by the Energy Information Administration (EIA), which legally requires direct reporting via survey for all energy generating units at or greater than 1 megawatt capacity. The TVA website also projects a 2017 date for the retirement of Units 1 and 2. The modeling report prepared for the Commonwealth presents inconsistent information, stating that a public announcement indicating TVA-Paradise Fossil Plant Units 1 and 2 are slated for retirement by April 2016, EPA said. The agency added: “In order for the shutdown to be considered for the designations which must be finalized by July 2, 2016, the EPA will need confirmation from the Commonwealth that this shutdown is in effect prior to final designations.”
EPA also noted that all units at the coal-fired Green River Generating Station in the region have been retired as of October 2015. That plant was owned by Kentucky Utilities and Louisville Gas and Electric. The remaining sources of SO2 emissions are at least 35 kilometers or more from Plant Wilson which is distant enough that their impacts would be significantly reduced in terms of impacts overlapping with those of Plant Wilson. The modeling analysis performed and submitted by the Commonwealth included only future allowable emissions from Plant Wilson and actual emissions from the surviving Unit 3 of TVA’s Paradise plant.
“The EPA notes inconsistent information on the timing of the retirement of TVA-Paradise Fossil Plant Units 1 and 2 (i.e., whether this will occur by April 2016 or June 2017). The EPA is required to characterize the current air quality around Plant Wilson by July 2, 2016, according to the terms of the court ordered consent decree. Therefore based on the uncertainty on the permanent shutdown of Units 1 and 2 and the fact that 2012-2014 actual historic emissions were not considered in the modeling analysis for Plant Wilson, the EPA does not have sufficient information to consider the source’s impact on the Ohio County Area. Unless the Commonwealth can provide documentation that Units 1 and 2 will permanently retire in advance of the July 2, 2016, designations to the EPA for consideration prior to the promulgation of final designations, the EPA cannot consider these shutdowns and instead believes that it is more appropriate for the Commonwealth to account for actual emissions for these units from 2012-2014 in any modeling to characterize the air quality around Plant Wilson for the Ohio County Area.
“Because Plant Wilson’s future allowable limit is not yet federally-enforceable and there is no indication of a 1-hour averaging time or a comparatively stringent longer term averaging period, coupled with the uncertainty surrounding the shutdown of TVA Paradise Station Units 1 and 2, the EPA intends to designate the Ohio County Area as unclassifiable due to the absence of relevant information. However, if the Commonwealth can: (1) establish Plant Wilson’s new allowable limit of 0.85 lb SO2/mmBTU as federally-enforceable (through an appropriate mechanism), by April 19, 2016; (2) document the 1-hour averaging time or as applicable, includes a longer term average limit that the EPA determines is comparatively stringent to a 1-hour limit at the critical emission value (pursuant to the SO2 Nonattainment Guidance); (3) confirm and document that TVA-Paradise Fossil Plant Units 1 and 2 will be permanently retired for the purposes of validating the modeling submitted for the area of analysis and informing final designations scheduled July 2, 2016; (4) notify the EPA of these conditions in advance of our promulgation of final designations, the EPA may be able to consider a designation of unclassifiable/attainment for the entirety of Ohio County.”