EPA disagrees with Texas on some areas affected by SO2 NAAQS

The U.S. Environmental Protection Agency sent a Feb. 11 letter to the state of Texas making designations of attainment or otherwise for several areas in the state under the agency’s SO2 NAAQS program, with all of those areas containing a coal-fired power plant.

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.

Texas submitted updated recommendations to EPA in September 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 as part of a settlement of a lawsuit filed by 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 Texas a letter and a supporting technical document with its preliminary decisions for areas in Texas subject to the July 2 deadline.

Goliad County (Coleto Creek power plant)

The Goliad 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 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 consideration. In 2012, the coal-fired Coleto Creek Power Station of GDF SUEZ emitted 16,218 tons of SO2, and had an emissions rate of 0.615 lbs SO2/mmBTU.

In its submission, Texas recommended that the area surrounding the Coleto Creek station, specifically the entirety of Goliad County, be designated as unclassifiable/attainment. EPA noted: “The state’s assessment and characterization were performed following the notion that any areas without appropriately cited and qualified monitors should be considered unclassifiable or attainment based on lack of evidence that a violation of the NAAQS has occurred and the results of air dispersion modeling software, i.e., AERMOD, analyzing actual emissions. 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 Goliad County as unclassifiable/attainment.”

Atascosa County (San Miguel power plant)

The Atascosa County area contains one source subject to this program. in 2012, the San Miguel Lignite Fired Power Plant emitted 10,950 tons of SO2, and had an emissions rate of 0.63 SO2/MMBTU. This plant is owned by San Miguel Electric Cooperative.

In its submission, Texas recommended that the area surrounding the San Miguel Power Plant, specifically the entirety of Atascosa County, be designated as unclassifiable/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 Atascosa County as unclassifiable/attainment,” said EPA.

Lamb County (Tolk power plant) 

The Lamb County area contains a stationary source that is subject to this rulemaking. In 2012, the coal-fired Tolk Electric Station of Xcel Energy emitted 19,168 tons of SO2, and had an emissions rate of 0.52 lbs/ SO2/mmBTU.

In its submission, Texas recommended that the area surrounding the Tolk station, specifically Lamb County, be designated as unclassifiable/attainment. Said EPA: “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 Lamb County as unclassifiable/attainment.”

Limestone County (Limestone power plant)

The Limestone area contains a stationary source that falls under this program. In 2012, the coal-fired Limestone Power Station of NRG Energy emitted 20,671 tons of SO2, and had an emissions rate of 0.36 lbs SO2/mmBTU.

In its submission, Texas recommended that the area surrounding the Limestone Power Station, specifically the entirety of Limestone County, be designated as attainment. The EPA received dispersion modeling results from the Sierra Club, asserting that the area around the Limestone Power Station experiences violations of the NAAQS, and urging the EPA to designate the area as nonattainment. Said EPA: “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 Limestone County as unclassifiable/attainment.” 

Robertson County (Twin Oaks power plant)

The Robertson County area contains a stationary source that falls under this program. In 2012, the coal-fired Twin Oaks Power Station emitted 4,038 tons of SO2, and had an emissions rate of 0.51 lbs SO2/MMBTU. The Twin Oaks plant was sold in a bankruptcy case in 2014 to Blackstone Group.

In its submission, Texas recommended that the area surrounding the Twin Oaks Power Station, specifically Robertson County, be designated as unclassifiable/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 Robertson County as unclassifiable/attainment,” said EPA.

For the Twin Oaks area, the state included the nearest SO2 source (the coal-fired Oak Grove Steam Electric Station) located within 21 kilometers of the Twin Oaks Power Station. The Oak Grove Steam Electric Station, reported 6,950 tons of SO2 in 2013. Although the state suggested that this source would be unlikely to cause a significant concentration gradient in the vicinity of the Twin Oaks Power Station, it was included in the state modeling.

Fort Bend County (W.A. Parish power plant)

The Fort Bend County area contains a stationary source that was evaluated under this program. In 2012, the coal-fired W.A. Parish Electric Generating Station of NRG Energy emitted 37,861 tons of SO2, and had an emissions rate of 0.49 lbs SO2/MMBTU.

Texas recommended that the area surrounding the W.A. Parish station, specifically the entirety of Fort Bend County, be designated as unclassifiable/attainment. The EPA received dispersion modeling results from the Sierra Club, asserting that the area around the W.A. Parish station experiences violations of the NAAQS, and urging the EPA to designate the area as nonattainment.

“After careful review of the state’s assessment, supporting and supplemental documentation, and all available modeling analyses submitted by industry and the Sierra Club, the EPA disagrees with the state’s recommendation for the area, and intends to designate the areas as unclassifiable on the basis that we do not have sufficient information available to designate the area as meeting or not meeting the NAAQS,” said EPA. “Based on our current review of all available analyses, we believe that the latest modeling from industry may support a designation of unclassifiable/attainment and is more consistent with the modeling approaches and refinements outlined in the EPA’s Modeling [Technical Assistance Document]. However, due to the date of receipt of the latest modeling from industry relative to our scheduled timeline for proposing designations in order to meet the court-ordered deadline, we have not had sufficient time to thoroughly review the January 25, 2016 submittal to determine if the modeling is sufficient to support a designation of unclassifiable/attainment. The EPA will continue our review of industry’s January 25, 2016 submittal and will take it into consideration in our final designation for the area around W.A. Parish station.”

McLennan County (Sandy Creek power plant) 

McLennan County contains a stationary source subject to evaluation. In 2012, the coal-fired Sandy Creek Energy Station, which is operated by LS Power, emitted 4,955 tons of SO2, and had an emissions rate of 1.41 lbs SO2/mmBTU based on EPA’s Air Markets Database. 

In its submission, Texas recommended that the area surrounding the Sandy Creek Energy Station, specifically the entirety of McLennan County, be designated as attainment. 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 recommendation for the area, and intends to designate McLennan County as unclassifiable.”

The Texas Commission on Environmental Quality (TCEQ) and Sandy Creek Energy Station have provided information that the EPA’s Air Markets Database emission data for 2012 for the facility is substituted emissions data and not measured emission data. On April 5, 2013 Sandy Creek Energy Station submitted a petition for an alternate methodology for reporting substituted emissions data. Based on this alternate methodology, revised reported emissions for the facility for 2012 would be 2,280 tpy, below the 2600 tpy threshold for consent decree sources. EPA has not acted on that petition at this time. If the petition is approved and the Air Market’s Database is updated to reflect this change by the deadline for designations, the EPA consent decree obligation to designate this area by July 2, 2016 would not apply.

Milam County (Sandow power plant)

Milam County contains one stationary source subject to decision. In 2012, the coal-fired Sandow Power Plant of Luminant emitted 22,511 tons of SO2, and had an emissions rate of 1.00 lbs SO2/mmBTU.

Texas provided no formal recommendation for the area surrounding the Sandow Power Plant. Instead, Texas provided a general recommendation of unclassifiable/attainment for the 243 counties, including Milam County, located in the state that do not have any operational SO2 regulatory monitors. Said EPA: “After review of the state’s submittal and based on the lack of information regarding the attainment status of the area surrounding the Sandow Power Plant, the EPA does not agree with the state’s recommendation for the area, and since the area cannot be classified on the basis of available information as meeting or not meeting the NAAQS, intends to designate Milam County as unclassifiable.”

Potter County (Harrington power plant) 

Potter County contains a stationary source that falls under the consent decree criteria. In 2012, the coal-fired Harrington Power Station of Xcel Energy emitted 15,383 tons of SO2, and had an emissions rate of 0.46 lbs SO2/mmBTU.

Texas provided no formal recommendation for the area surrounding the Harrington Power Station. Instead, Texas provided that general recommendation of unclassifiable/attainment for the 243 counties located in the state, including Potter County, that do not have any operational SO2 regulatory monitors. Said EPA: “After review of the state’s submittal and based on the lack of information regarding the attainment status of the area surrounding the Harrington Power Station, the EPA does not agree with the state’s recommendation for the area, and, since the area cannot be classified on the basis of available information as meeting or not meeting the NAAQS, intends to designate the area as unclassifiable.”

Rusk County (Martin Lake power plant)

The Rusk County area contains a stationary source subject to the consent decree. In 2012, the Martin Lake Electrical Station of Luminant emitted 43,093 tons of SO2, and had an emissions rate of 0.5504 lbs SO2/mmBTU.

In its submission, Texas recommended that the area surrounding Martin Lake station, specifically Rusk County, be designated as unclassifiable/attainment. This assessment and characterization was performed using the logic that any areas without appropriately cited and qualified monitors should be considered unclassifiable or attainment based on lack of evidence that a violation of the NAAQS has occurred. “After careful review of the state’s assessment, supporting documentation, and all available data, the EPA does not agree with the state’s recommendation for this area, and intends to designate the area as nonattainment,” said EPA.

Titus County (Monticello power plant)

The Titus County area contains a stationary source subject the decree. In 2012, the coal-fired Monticello Steam Electric Station emitted 31,447.2 tons of SO2, and had an emissions rate of 0.784 lbs SO2/mmBTU. Martin Lake is a Luminant power plant.

In its submission, Texas recommended that the area surrounding Monticello station, specifically Titus County, be designated as unclassifiable/attainment. The state’s assessment and characterization was performed following the notion that any areas without appropriately cited and qualified monitors should be considered unclassifiable or attainment based on lack of monitored evidence that a violation of the NAAQS has occurred. 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 recommendation for this area, and intends to designate the areas as nonattainment.”

Freestone County (Big Brown power plant)

The Freestone County area contains a stationary source subject to consideration. In 2012, the coal-fired Big Brown Steam Electric Station emitted 60,681 tons of SO2, and had an emissions rate of 1.59 lbs SO2/mmBTU. This is a Luminant power plant.

In its submission, Texas recommended that the area surrounding Big Brown, specifically Freestone County, be designated as unclassifiable/attainment. The state’s assessment and characterization was performed following the notion that any areas without appropriately cited and qualified monitors should be considered unclassifiable or attainment based on a lack of monitored evidence that a violation of the NAAQS has occurred. 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 recommendation for this area, and intends to designate the areas as nonattainment.”

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.