EPA gives a pass to three Nebraska coal plants on SO2 NAAQS findings

The U.S. Environmental Protection Agency on Feb. 16 told the state of Nebraska that areas around two coal-fired power plants are in attainment for the SO2 NAAQS, while another area with a coal plant can’t currently be classified as being in nonattainment, which avoids new restrictions on plant emissions.

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 Nebraska submitted updated recommendations to EPA in September 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. The court was responding to an environmental group lawsuit. 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. On Feb. 16, EPA sent a letter to Missouri outlining its preliminary findings for three affected areas in the state.

“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 the Nebraska City Station as unclassifiable/attainment for the 2010 SO2 NAAQS,” said EPA about one of the areas evaluated. “Specifically, the boundaries are comprised of the entirety of Otoe County, Nebraska. The unclassifiable/attainment designation is based on the modeling analysis that the State of Nebraska provided to EPA.”

In 2012, the Omaha Public Power District’s (OPPD) Nebraska City Station emitted 16,766 tons of SO2 and had an emissions rate of 0.722 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, Nebraska recommended that the area surrounding the Nebraska City Station be designated as attainment. EPA has agreed.

The 1,343-MW Nebraska City Station is located in southeast Nebraska in the eastern portion of Otoe County. The Nebraska City Station lies near and within the Missouri River Valley along the Nebraska and Iowa border. The Nebraska City Station includes two coal boiler stacks. No significant emitters of SO2 are located nearby the Nebraska City Station.

As for the two other areas in Missouri covered by EPA’s Feb. 16 preliminary findings:

Lincoln County (Gerald Gentleman power plant)

Said EPA: “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 the Gerald Gentleman Station as unclassifiable/attainment for the 2010 SO2 NAAQS. Specifically, the boundaries are comprised of the entirety of Lincoln County, Nebraska. The unclassifiable/attainment designation is based on the modeling analysis that the State of Nebraska provided to EPA.”

In 2012, the Nebraska Public Power District’s (NPPD) Gerald Gentleman Station emitted 26,437 tons of SO2 and had an emissions rate of 1.05 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, Nebraska recommended that the general area surrounding the 1,365-MW Gerald Gentleman Station be designated as attainment, with EPA in agreement.

The Gerald Gentleman Station is located in west-central Nebraska in the western portion of Lincoln County. It lies near the small community of Sutherland, Nebraska, and near the Platte River Valley. The Gerald Gentleman Station includes two coal boiler stacks. No other significant emitters of SO2 are located near the Gerald Gentleman Station or within Lincoln County.

Lancaster County (Sheldon plant)

Said EPA: “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 Sheldon Station as unclassifiable for the 2010 SO2 NAAQS. Specifically, the boundaries are comprised of the entirety of Lancaster County, Nebraska. The unclassifiable designation is based on shortcomings from the modeling analyses that were submitted by both the state of Nebraska and the Sierra Club.”

EPA added: “The two modeling scenarios that the state conducted relied upon changes to the current Sheldon Station operations that would either reduce emissions or enhance dispersion of emissions but do not appear likely to be completed by July 2, 2016. Both modeling scenarios submitted by the Sierra Club use a background value that EPA believes is not representative of the area surrounding the Sheldon Station facility. Therefore the EPA did not have a reliable modeling analysis to designate this area at this time.”

In 2012, the Nebraska Public Power District’s 225-MW Sheldon Station emitted 2,760 tons of SO2 and had an emissions rate of 0.92 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, Nebraska recommended that the area around Sheldon Station be designated as unclassifiable. The state performed two modeling scenarios that purported to demonstrate compliance with the SO2 1-hr NAAQS based on actual emissions that would result from changes that would either reduce actual emissions or enhance dispersion of emissions. One modeling scenario relies upon increasing the stack heights for both boiler units (Units 1 and 2) at the Sheldon Station. The second modeling scenario relies upon increasing the stack height for Unit 1 and ceasing the combustion of coal for Unit 2. These two modeling scenarios depend upon changes to the current Sheldon Station operations that, if adopted, would affect actual emissions. The changes for Unit 2 under either scenario do not appear likely to be completed by July 2, 2016.

The Sheldon Station is located in southeastern Nebraska in the southern portion of Lancaster County. It includes two coal-fired boilers. There are no other significant emitters of SO2 within 20 kilometers of the Sheldon Station.

Notable is that the Nebraska Public Power District in April 2015 announced a plan to replace this year a 125-MW coal-fired boiler at its Sheldon plant with electricity derived from cleaner-burning hydrogen fuel. The hydrogen will be produced by Monolith Materials as a co-product from its production of carbon black using natural gas as a feedstock. Officials expect this would be the largest utility-scale use of hydrogen technology to generate electricity thus far.

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.