Oklahoma agency takes comment on NOx controls for Muskogee

The Oklahoma Department of Environmental Quality on Dec. 6 released for public comment a draft air permit to allow Oklahoma Gas & Electric (OG&E) to, at its coal-fired Muskogee plant, add low-NOx burners (LNB) and overfire air (OFA) to Units 4 and 5 to reduce emissions of NOx for the purpose of meeting Best Available Retrofit Technology (BART) requirements.

LNB and OFA are two forms of combustion control that have been combined in a single technology to reduce NOx emissions from pulverized coal fired units, the agency noted.  All LNBs offered commercially for application to coal fired boilers control the formation of NOx through some form of staged combustion. OFA works by reducing the excess air in the burner zone, thereby enhancing the combustion staging effect of the LNBs and further reducing NOX emissions.

OG&E’s project contractor has guaranteed emission results under specified test conditions of 0.15 lb/mmBtu of NOx and 0.37 lb/mmBtu of carbon monoxide (CO) for each unit, the agency said.

Muskogee utilizes sub-bituminous coal, natural gas, and some waste products to produce electricity. Muskogee Units 4, 5 and 6 use natural gas as a start-up fuel and sub-bituminous low-sulfur Wyoming coal as the primary fuel. The facility became commercially operational in 1956. Units 4, 5 and 6 are coal-fired units. Units 1, 2 and 3, the oldest units, have been retired or demolished.

OG&E has also requested a construction permit from the Oklahoma Department of Environmental Quality for the coal-fired Sooner plant to add low-NOX burners and overfire air to Units 1 and 2 to reduce emissions of NOX to meet BART requirements. The DEQ on Nov. 27 began taking public comment on the draft permitting for that project.

Utility in court against EPA over BART rules

OG&E parent OGE Energy (NYSE: OGE) said in its Nov. 7 Form 10-Q report that the need for NOx controls under BART is being driven, in part, by a contested 2010 State Implementation Plan (SIP) under the regional haze rule of the U.S. Environmental Protection Agency.

“The Oklahoma SIP included requirements for reducing emissions of NOX and SO2 from OG&E’s seven BART-eligible units at the Seminole, Muskogee and Sooner generating stations,” said the Form 10-Q. “The SIP also included a waiver from BART requirements for all eligible units at the Horseshoe Lake generating station based on air modeling that showed no significant impact on visibility in nearby national parks and wilderness areas. The SIP concluded that BART for reducing NOX emissions at all of the subject units should be the installation of low NOX burners with overfire air (flue gas recirculation was also required on two of the units) and set forth associated NOX emission rates and limits. OG&E preliminarily estimates that the total capital cost of installing and operating these NOX controls on all covered units, based on recent industry experience and past projects, will be approximately $100 million.”

With respect to SO2 emissions, the SIP included an agreement between the Oklahoma DEQ and OG&E that established BART for SO2 control at four coal-fired units at Sooner and Muskogee as the continued use of low-sulfur coal (along with associated emission rates and limits). The SIP specifically rejected the installation of dry scrubbers as BART for SO2 control from these units because the state determined that dry scrubbers were not cost effective.

The Form 10-Q added: “On December 28, 2011, the EPA issued a final rule in which it rejected portions of the Oklahoma SIP and issued a [Federal Implementation Plan] in their place. While the EPA accepted Oklahoma’s BART determination for NOX in the final rule, it rejected Oklahoma’s SO2 BART determination with respect to the four coal-fired units at the Sooner and Muskogee generating stations. The EPA is instead requiring that OG&E meet an SO2 emission rate of 0.06 pounds per MMBtu within five years. OG&E could meet the proposed standard by either installing and operating Dry Scrubbers or fuel switching at the four affected units. OG&E estimates that installing Dry Scrubbers on these units would include capital costs to OG&E of more than $1.0 billion. OG&E and the state of Oklahoma filed an administrative stay request with the EPA on February 24, 2012. The EPA has not yet responded to this request. OG&E and other parties also filed a petition for review of the FIP in the U.S. Court of Appeals for the Tenth Circuit on February 24, 2012 and a stay request on April 4, 2012. On June 22, 2012, the U.S. Court of Appeals for the Tenth Circuit granted the stay request.”

OGE noted that the stay will remain in place until a decision on the petition for review is complete, which will delay the implementation of the regional haze rule in Oklahoma. On June 15, 2012, OG&E, the state of Oklahoma and other parties filed a court brief in support of the petition for review of the final regional haze rule of the EPA. The briefing by all parties was completed in October.

Said the utility in its Oct. 9 court brief: “EPA overstepped its authority when it vetoed Oklahoma’s BART determination under the Clean Air Act’s (‘CAA’s’) Regional Haze program and replaced it with EPA’s own analysis. The CAA unequivocally grants Oklahoma the authority to make BART determinations for sources within its borders. In this case, the State properly exercised that authority and made a BART determination that met its statutory obligations. The State’s determination, however, did not satisfy EPA’s over-arching desire to have scrubbers installed on coal-fired power plants. EPA thus put itself in Oklahoma’s place and hired a consultant, conducted its own BART analysis, and issued a Final Rule requiring scrubbers. EPA had no authority to act in this manner, and, for this reason alone, the Final Rule cannot be sustained. Moreover, EPA’s BART determination is arbitrary and capricious in that it departs from EPA’s own guidance and is based on novel theories that were not presented for notice-and-comment.”

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.