EPA fails area around Muskogee coal plant in Oklahoma in its SO2 NAAQS review

The U.S. Environmental Protection has failed one of three areas in Oklahoma, where Oklahoma Gas and Electric‘s Muskogee power plant is located, when it comes to nonattainment of 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.

Oklahoma submitted updated recommendations to EPA in August 2015, ahead of a July 2, 2016, deadline for the EPA to designate certain areas around the country established by the U.S. District Court for the Northern District of California in a March 2015 order. That order was part of a lawsuit settlement with two environmental groups. This July 2 deadline is the first of three deadlines established by the court for the EPA to complete area designations for the 2010 SO2 NAAQS. EPA on Feb. 11 sent to Oklahoma its preliminary determinations on three areas in the state subject to the July 2 deadline.

Muskogee County (Muskogee power plant) 

The Muskogee County 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 in 2012 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 had not met the specific requirements for being “announced for retirement,” which would exclude it from this rulemaking. In 2012, Oklahoma Gas and Electric’s (OG&E) Muskogee Generating Station emitted 22,647 tons of SO2, and had an emissions rate of 0.50 lbs SO2/mmBTU.

In its submission, Oklahoma recommended that the area surrounding the Muskogee station, specifically the entirety of Muskogee County, be designated as unclassifiable. Said EPA: “After careful review of the state’s assessment, supporting documentation, and all available data, the EPA does not agree with the state’s county area recommendation for designation. Instead, we intend to designate the area around Muskogee station as nonattainment with these boundaries: a 17.5 km rectangular area surrounding the facility (3.0 km x 5.85 km).”

The Muskogee station is located in eastern Oklahoma in the northeastern portion of Muskogee County.

Oklahoma provided three scenarios of Muskogee’s emissions. The scenario EPA evaluated used 2012-2014 CEMS data (denoted as Scenario 1 by Oklahoma). Oklahoma’s two other scenarios that were a combination of actual emissions and a switch to natural gas (NG) on some units. These two scenarios were Scenario 2 (Muskogee station Unit 4 converted to NG and Units 5 and 6 based on 99th percentile level of 2013-2014 actuals) and Scenario 3 (Muskogee station Units 4 and 5 converted to NG and Unit 6 based on 99th percentile level of 2013-2014 actuals). Since neither Scenario 2 nor Scenario 3 will be enforceable by the required date for these designations, EPA’s review focused on Oklahoma’s Scenario 1 modeling.

Choctaw County (Hugo power plant)

The Choctaw County area contains a stationary source that also fell under this progream. In 2012, Western Farmers Electric Cooperative‘s coal-fired Hugo Generating Station emitted 8,066 tons of SO2, and had an emissions rate of 0.60 lbs SO2/mmBTU. 

In its submission, Oklahoma recommended that the area surrounding WFEC Hugo station, specifically the entirety of Choctaw County, be designated as attainment, Said EPA: “After careful review of the state’s assessment, supporting documentation, and all available data, the EPA intends to designate Choctaw County as unclassifiable/attainment.”

The WFEC Hugo station is located in southeastern Oklahoma in the eastern portion of Choctaw County.  

Noble County (Sooner power plant)

The Noble County area contains a stationary source that qualifies for SO2 NAAQS consideration. In 2012, the OG&E Sooner Generating Station emitted 15,884 tons of SO2, and had an emissions rate of 0.50 lbs SO2/mmBTU.

In its submission, Oklahoma recommended that the area surrounding the Sooner station, specifically the entirety of Noble County, be designated as attainment. “After careful review of the state’s assessment, supporting documentation, and all available data, the EPA agrees that the area is attaining the standard, and intends to designate Noble County as unclassifiable/attainment,” said the agency.

The Sooner station is located in northcentral Oklahoma in the central portion of Noble County.

OG&E pursuing scrubbers to control SO2 at Sooner

Notable is that OG&E on Feb. 12 petitioned the Oklahoma Corporation Commission for expedited approval of the $500 million installation of dry scrubbers on the two units of the Sooner coal plant, with those controls needed to comply with a January 2019 deadline under EPA’s regional haze rule.

The commission in December 2015 rejected the company’s Environmental Compliance Plan (ECP), which included this project. The company said in the Feb. 12 application that it is now seeking approval of that plan only as it relates to the Sooner scrubber project. Other projects needed for air compliance – low-NOx burners installed at seven units, activated carbon injection installed on five coal units for mercury control, and the coal-to-gas conversions of Muskogee Units 4 and 5 – will be addressed in later, separate proceedings. Those Muskogee conversions would solve the issue with SO2 in the area around the plant, but EPA in its SO2 NAAQS decisionmaking can’t consider such projects unless they are under a legally enforceable obligation.

The company had already executed scrubber installation contracts for Sooner, but has suspended work under those contracts until May 2 of this year while it awaits a commission action. The next phase of the project includes site mobilization, which will mean a major increase in money spent so far under the contracts. The utility said it needs to resume construction by May 2 to meet the January 2019 deadline under the regional haze rule. OG&E said if it can’t get the Sooner scrubbers approved in a timely way, it would have to look at converting these two units to natural gas, further sacrificing fuel diversity on its system.

OG&E’s coal-fired units are:

Muskogee Unit 4, on-line since 1977, 492 MW;

Muskogee Unit 5, on-line since 1978, 506 MW;

Muskogee Unit 6, on-line since 1984, 500 MW;

Sooner Unit 1, on-line since 1979, 520 MW; and

Sooner Unit 2, on-line since 1980, 522 MW.

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.