The U.S. Environmental Protection Agency said that various consent decrees and utility clean-air programs will take largely care of the coal-fired issues raised by parties criticizing its approval of a regional haze plan for the state of Kentucky.
In the March 30 Federal Register, EPA published a final approval, and a limited disapproval, of two revisions to the Kentucky State Implementation Plan (SIP) submitted by the Kentucky Energy and Environment Cabinet in June 2008 and May 2010. These revisions address the requirements that states to prevent any future and remedy any existing anthropogenic impairment of visibility in mandatory Class I areas (national parks and wilderness areas). States are required to assure reasonable progress toward the national goal of achieving natural visibility in Class I areas.
EPA has approved these Kentucky revisions as a whole, but disapproved certain technical parts that relied on the court-invalidated Clean Air Interstate Rule (CAIR). EPA has decided that its recently-issued CAIR replacement, the Cross-State Air Pollution Rule (CSAPR), is stronger in terms of regional haze reduction than CAIR in the affected states.
Most of the March 30 notice was devoted to responding to comments from unnamed parties about the proposed SIP approval/disapproval that EPA published last December.
Kentucky Power-Big Sandy Units 1-2. One commenter contended that the Best Available Retrofit Technology (BART) analysis for American Electric Power’s (NYSE:AEP) coal-fired Big Sandy units 1-2 fails to consider: wet electrostatic precipitators (ESPs); switching to a lower sulfur coal either entirely or co-firing it with natural gas or biomass; a circulating fluid bed (CFB) scrubber; a spray dry absorption (SDA) scrubber; a fabric filter (FF); upgrading the current ESPs to increase the size and/or change from wire to rigid discharge electrode; changing the operation of the air preheater; or trona injection coupled with replacing the ESP with a new ESP.
Because the BART analysis allegedly failed to consider all available retrofit technologies, the commenter contended that EPA must disapprove the SIP with regard to the particulate (PM) BART determination for Big Sandy. The commenter also believes that EPA must disapprove the SIP because it does not contain a ‘‘firm’’ closure date for Big Sandy Unit 1; an enforceable deadline for the installation of the flue gas desulfurization (FGD) on unit 2 and the ammonia injection on unit 1; and an emissions limit for condensable PM from both units.
Available retrofit control options are those air pollution control technologies with a practical potential for application to the emissions unit and the regulated pollutant under evaluation, EPA responded. “In identifying “all” options, a state must identify the most stringent option and a reasonable set of options for analysis that reflects a comprehensive list of available technologies. It is not necessary to list all permutations of available control levels, EPA said.
AEP performed a full BART analysis for particulates, with its primary focus on the condensable fraction due to the minimal impact from the primary particulates since both units are currently equipped with ESPs for primary particulate control. For unit 2, AEP considered injecting ammonia, injecting trona, or installing a wet FGD system. In addition, AEP determined that the options involving injecting trona on either unit at Big Sandy were technically infeasible.
For Big Sandy units 1 and 2, the company agreed to install ammonia injection controls on unit 1 and a FGD on unit 2. EPA agrees with Kentucky’s analyses and conclusions on this point.
In June 2011, AEP announced that Big Sandy unit 1 would be retired by Dec. 31, 2014, and Unit 2 would be rebuilt as a natural gas-fired plant by Dec. 31, 2015. Since that announcement, AEP modified its plans to convert Unit 2 from coal to gas. It now plans to construct a dry FGD on the 800-MW Unit 2. However, AEP still plans to shut down Unit 1 (the older of the two; rated at 278 MW) and to retire it at the end of 2014. In December 2011, the company applied at the Kentucky Public Service Commission for a needed approval of this plan, with that case still pending.
As AEP’s Kentucky Power subsidiary continues the required proceedings for closure of Unit 1, requiring additional analysis would not likely change things, said EPA. If the decision to close Unit 1 should be reversed, the requirements for an ammonia scrubber remain in place.
Louisville Gas and Electric, Mill Creek. Another commenter had issues with the Mill Creek plant of LG&E, which is part of PPL Corp. (NYSE:PPL) The commenter said that EPA should clarify whether the 99% removal efficiency for the existing ESP at the coal-fired Mill Creek plant is for filterable or condensable PM. If it is filterable, the commenter said it is arbitrary to base a BART analysis on the current removable rate for filterable PM when the BART analysis is supposed to address condensable PM.
The commenter also stated that the BART analysis rejects pulse jet fabric filter (PJFF) and wet ESP based solely on the incremental cost and admits that the average cost effectiveness for sorbent injection on all four units is about the same.
The commenter further contended that EPA must disapprove Kentucky’s regional haze SIP with regard to the PM BART analysis for Mill Creek since the analysis fails to consider: switching to a lower sulfur coal either entirely or as a blend or co-firing natural gas or biomass; CFB scrubbers; SDA scrubbers; upgrading existing scrubbers; upgrading the current ESPs to increase the size and/or change from wire to rigid discharge electrode; or changing the operation of the air preheater.
EPA responded that the existing ESP removal efficiency referred to by the commenter is for filterable particulates. These filterable emissions, which are 99% controlled, are a substantial portion of the facility’s potential PM emissions and maintaining these limits for regional haze is appropriate, EPA added. For the two units where additional PM controls are being adopted for BART, the state has adopted additional emissions limits to handle condensable PM to address those emissions not controlled by the filterable emissions limit.
The title V permitted BART emissions limits for Mill Creek Units 3 and 4 are 64.3 pounds per hour (lb/hr) and 76.5 lb/hr, respectively, for sulfuric acid mist. These are new BART limits for the two units for which controls on condensable particulates are being installed, EPA said.
Regarding the technologies considered in the BART analysis for Mill Creek, available retrofit control options are those air pollution control technologies with a practical potential for application to the emissions unit and the regulated pollutant. In identifying “all” options, a state must identify the most stringent option and a reasonable set of options. It is not necessary to list all permutations of available control levels that exist for a given technology, EPA said.
Furthermore, EPA does not consider BART as a requirement to redesign the source when considering available control alternatives. For example, EPA does not require the BART analysis to consider building a natural gas-fired turbine although the turbine may be inherently less polluting. Also, EPA does not interpret the rules as requiring states to consider limiting the type of coal burned as a BART-control technology.
The existing cold-side ESPs at all four units at Mill Creek are already demonstrating high PM removal efficiencies of 99%, and all four units are already equipped with wet FGD systems for SO2 removal, limiting the additional available options for sulfite (SO3) condensable particulate control. Kentucky determined that BART for Mill Creek is the installation of sorbent injection controls on the larger Units 3 and 4. Kentucky did not require BART controls on Units 1 and 2 because controls on these units would nearly double the cost to achieve limited visibility improvement.
East Kentucky Power Cooperative, Spurlock and Cooper. Another commenter contended that EPA must disapprove the BART determinations for East Kentucky Power Cooperative’s (EKPC) coal-fired Spurlock and Cooper plants since the BART analysis provides no limit on condensable PM and fails to consider switching to a lower sulfur coal either entirely or as a blend; co-firing natural gas or biomass; or changing the operation of the air preheater.
Available retrofit control options are those air pollution control technologies with a practical potential for application, EPA responded. In identifying “all” options, a state must identify the most stringent option and a reasonable set of options and it is not necessary to list all permutations of available control levels that exist for a given technology.
EKPC evaluated three options and agreed to install the top ranking option of wet FGD for SO2 control and wet ESP for PM control for both Spurlock and Cooper. These controls are consistent with those in a consent decree between EKPC and EPA that will address condensable particulate emissions and other visibility impairing pollutants, EPA noted. Kentucky later modified this BART determination in its May 2010 regional haze SIP revision with a comparably effective option at Cooper Units 1 and 2 of dry FGD and FF emissions controls for the wet FGD and wet ESP controls. “EPA believes that Kentucky has appropriately addressed BART for this facility,” the agency added.
Tennessee Valley Authority, Paradise. For the Tennessee Valley Authority’s (TVA) Paradise coal plant, a commenter contended that the BART analysis fails to consider switching to a lower sulfur coal (either entirely or as a blend); co-firing natural gas or biomass; a wet FGD; a dry CFB scrubber; a SDA scrubber; or changing the operation of the air preheater. Again, EPA responded that available retrofit control options are those technologies with a practical potential at the emissions unit and it is not necessary to list all permutations of control levels that exist for a given technology.
All three units at Paradise are already equipped with FGD systems. These systems are in the process of being upgraded, and TVA believes that the work should be completed by the end of 2012. The BART analysis focused on control of condensable PM. TVA concluded that neither of the two control options evaluated (wet ESP and hydrated lime injection) were cost effective, and the state concurred. TVA plans to install hydrated lime injection controls on Paradise Units 1–3 to mitigate opacity due to SO3 emissions, and these controls are required to be in place under a 2009 title V permit for the facility. “EPA therefore believes that Kentucky has appropriately addressed BART for this facility, EPA concluded.