EPA rejects arguments about Big Sandy coal plant emissions

The U.S. Environmental Protection Agency rejected a couple of arguments about emissions from the Big Sandy coal plant owned by American Electric Power (NYSE: AEP) in approving a revision to the Kentucky state implementation plan (SIP).

This revision was submitted by the state to EPA in December 2008 for the purpose of providing for attainment of the 1997 fine particulate matter (PM2.5) national ambient air quality standards (NAAQS) in the Kentucky portion of the Huntington-Ashland, West Virginia-Kentucky-Ohio PM2.5 nonattainment area, EPA noted in an April 11 Federal Register notice.

The Kentucky plan at issue in this action pertains only to the Kentucky portion of the Huntington-Ashland Area. As proposed on Jan. 30, EPA approved Kentucky’s PM2.5 attainment plan.

EPA in the April 11 final approval responded to adverse comments received on the proposed approval of Kentucky’s PM2.5 attainment plan, with two of those comments having to do with Big Sandy.

One commenter said that the Big Sandy plant in Lawrence County is the largest single source of PM2.5 precursor emissions in the Huntington-Ashland Area and raises several issues associated with Kentucky’s treatment of the plant’s emissions. The commenter said that state’s attainment year modeling relies on artificially low emissions from Big Sandy because Kentucky modeled attainment during 2008, which the commenter states was the “largest economic recession in recent times,” which backed down plant usage and emissions. The unidentified commenter concluded by saying that EPA must require Kentucky’s SIP to include enforceable limits for both Big Sandy units, restricting emissions to the lowest levels achieved during the attainment modeling years, 2007–2011.

As an initial point of clarification, EPA responded, Kentucky modeled attainment during 2009, not 2008. Additionally, as shown in EPA’s Jan. 30 proposal notice, all 2009 predicted (modeled) annual PM2.5 design values for the monitors of the Huntington-Ashland Area were higher than the values actually measured at those sites in 2009. Further, the emissions assumed for the Big Sandy plant were projections based upon the state’s knowledge of the facility’s future plans when the modeling was performed, not actual emissions that occurred in 2008. Based on actual ambient data, EPA has already determined that the area attained the 1997 Annual PM2.5 standard by its April 5, 2010, attainment date. The 2008 economic downturn was irrelevant to, and in fact occurred after, the modeling results were produced, EPA noted.

Finally, EPA found that the modeling conducted for the 2009 attainment year used the VISTAS Best & Final emissions inventory. This inventory shows Big Sandy Unit 1 having neither selective catalytic reduction (SCR) nor a scrubber in 2009, and Unit 2 having SCR since 2003 but no scrubber in 2009. This is consistent with what is shown for these units on EPA’s Clean Air Market Division’s website. For these reasons, EPA has determined that the commenter has not provided a basis on which to disapprove the revision with respect to the modeling issues.

With regard to the commenter’s statements about emission limits, the Big Sandy facility has numerous emission limitations for relevant pollutants, EPA noted. In addition, the facility was included in the October 2007 federal consent decree resolving an air enforcement matter between EPA and AEP. The facility is also subject to a number of other Clean Air Act programs including but not limited to the regional haze program.

As part of Kentucky’s regional haze SIP, on which EPA recently took final action, the facility will be installing ammonia injection controls on Unit 1 and flue gas desulfurization on Unit 2. Through these and other requirements, the facility is subject to enforceable emission limits. For these reasons, EPA disagreed that the commenter has identified a basis on which EPA should disapprove Kentucky’s attainment plan.

AEP’s Kentucky Power subsidiary is currently before the Kentucky Public Service Commission seeking approval for the Unit 2 scrubber. At one point last year, AEP planned to shut both units at Big Sandy, but later decided to scrub Unit 2 and shut only the smaller, older Unit 1.

A second commenter said that the state of Kentucky’s attainment demonstration modeling lists emission controls at Big Sandy inaccurately. The commenter contended that the state made adjustments to its Integrated Planning Model (IPM) results for the 2009 and 2018 electric generating unit (EGU) inventories to account for various control measures and that this renders the state’s modeling flawed for the attainment year of 2009. The commenter concluded that EPA should require the state to include in the Kentucky SIP an enforceable schedule for installation of a SCR and scrubber at Big Sandy.

As noted in the response to the first commenter, EPA said the modeling presented by Kentucky used the correct assumptions about emission controls at Big Sandy in 2009. The 2002 emissions inventory was based on data that was developed by the VISTAS contractors and submitted by the states to the 2002 National Emissions Inventory. Kentucky indicated that Big Sandy Unit 1 was not expected to have a scrubber or SCR control operational in 2009 (IPM had projected these controls would be in use by Big Sandy Unit 1 in 2009). In February 2008, VISTAS used this updated information in completing the Best & Final inventory, which was used in the modeling relied upon by Kentucky. EPA also again noted that Big Sandy is subject to emissions limits under several EPA rules and the consent decree.

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.