EPA rejects Louisiana SO2 NAAQS findings for areas around two power plants

The U.S. Environmental Protection Agency told the state of Louisiana in a Feb. 11 letter that it can’t designate the area around the coal-fired Dolet Hills power plant as being in attainment with the SO2 NAAQS program.

Under section 107(d) of the Clean Air Act (CAA), 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 defined as 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 state of Louisiana submitted updated recommendations to EPA in November 2015, ahead of a July 2, 2016, deadline for the EPA to designate certain areas established by the U.S. District Court for the Northern District of California as being in attainment or not. EPA lately has sent out a number of letters to different states with preliminary decisions ahead of the July 2 deadline. This deadline is the first of three deadlines established by the court for the EPA to complete area designations for the 2010 SO2 NAAQS. 

EPA noted that the Dolet Hills Power Station is 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 pounds of SO2 per one million British thermal units (lbs SO2/mmBTU). As of March 2, 2015, this stationary source has not met the specific requirements for being “announced for retirement,” which would exclude it from this process.

Specifically, in 2012, the Dolet Hills Power Station (Dolet Hills) emitted 20,887 tons of SO2, and had an emissions rate of 0.80 lbs SO2/mmBTU. Pursuant to the March 2, 2015 consent decree, the EPA must designate the area surrounding the facility by July 2, 2016.

In its November 2015 recommendation, the Louisiana Department of Environmental Quality (LDEQ), recommended that the area surrounding Dolet Hills, specifically the southeast quadrant of DeSoto Parish, be designated as unclassifiable based on information included in a monitoring siting report. The report assessed and characterized air quality for the facility and other nearby sources.

“Our review and analysis indicated that this initial modeling intended to justify the siting of monitors did not follow either the monitoring TAD or modeling TAD in certain respects and only provided normalized estimates of impacts rather than absolute results,” EPA noted. “The EPA also received air modeling performed by Sierra Club (initially in September 2015 and updated in December 2015), asserting that the area around Dolet Hills experiences impacts in exceedance of the NAAQS. The state reviewed this modeling, and subsequently performed its own revised modeling using the input parameters provided by Sierra Club. These assessments and characterization were performed using air dispersion modeling software, i.e., AERMOD, analyzing actual emissions. However, the state factored and used the currently non-default beta option low wind speed modification (LOWWIND3). This revised modeling using LOWWIND3 predicted peak concentrations slightly below the NAAQS. As a result, the state changed its unclassifiable recommendation to attainment.”

However, LDEQ performed air dispersion modeling intended to characterize air quality as a result of SO2 emissions from Dolet Hills without prior consultation with and approval from an EPA Regional Office of its beta methods, and therefore has not met the applicable regulatory requirements, said EPA. “As a result, the EPA does not believe that the air quality modeling results obtained from the use of these beta options can be used as a reliable indicator of attainment status in the area around Dolet Hills until appropriate alternative model approval is granted or these beta options are promulgated as regulatory options in AERMOD through EPA rulemaking.”

The agency added: “After careful evaluation of the state’s recommendation and supporting information, as well as all available relevant information, the EPA intends to designate the area around Dolet Hills in DeSoto Parish, Louisiana as nonattainment for the 2010 SO2 NAAQS.”

Dolet Hills is a 650-MW, lignite-fired plant operated by Cleco Power. Dolet Hills is co-owned by Cleco Power, a subsidiary of Cleco Corp., and Southwestern Electric Power Co., which is a unit of American Electric Power.

Also evaluated by EPA was the state’s recommendation for the Calcasieu Parish area, which contains two stationary sources that, according to the EPA’s Clean 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 pounds of SO2 per one million British thermal units (lbs SO2/mmBTU). As of March 2, 2015, these stationary sources have not met the specific requirements for being “announced for retirement.”

Specifically, in 2012: Entergy‘s Nelson Electric Generating Plant emitted 12,513 tons of SO2 with an emissions rate of 0.7 lbs SO2/mmBTU; and Entergy’s Nelson Industrial Steam Co. facility emitted 6,706 tons of SO2 with an emissions rate of 0.7 lbs SO2/mmBTU. Under the March 2015 consent decree, the EPA must designate the area surrounding these facilities by July 2, 2016.

In its submission, Louisiana recommended that the area surrounding the Nelson Electric Generating Plant and the Nelson Industrial Steam facility, specifically the entirety of Calcasieu Parish, be designated as attainment. This air quality assessment was performed using air dispersion modeling software, i.e., AERMOD, analyzing actual emissions by a group of local industries and then provided to the state.

“After careful review of the industry and state’s assessment, supporting documentation, and all available data, the EPA does not agree with the state’s recommendation for the area, and intends to designate the area as unclassifiable,” said the agency. “Specifically, the area we intend to designate unclassifiable consists of Calcasieu Parish.”

Both the Nelson Electric Generating Plant and the Nelson Industrial Steam Co. are located in southwestern Louisiana in the central portion of Calcasieu Parish. The facilities are basically adjacent to each other. Two of the units at the Nelson power plant are fired with gas and oil, while Unit 6 is coal-fired.

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.