Due to a disagreement about how to handle certain coal-fired facilities, including American Electric Power’s (NYSE:AEP) Flint Creek plant, the U.S. Environmental Protection Agency on March 12 partially approved a revision to the Arkansas State Implementation Plan (SIP) intended to address the regional haze (RH) requirements of the Clean Air Act (CAA).
In addition, in a March 12 Federal Register notice, EPA said it is partially approving and partially disapproving the portion of the Arkansas Interstate Transport SIP submittal that addresses the visibility requirement of a section for the 1997 8-hour ozone and 1997 fine particulate matter (PM2.5) national ambient air quality standards (NAAQS) that the Arkansas SIP contain adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility.
EPA approved certain core elements of the RH SIP including: identification of affected Class I areas; determination of baseline and natural visibility conditions; determination of Uniform Rate of Progress (URP); reasonable progress goal (RPG) consultation and long term strategy (LTS) consultation; coordination of RH and reasonably attributable visibility impairment (RAVI); regional haze monitoring strategy and other SIP requirements; commitment to submit periodic regional haze SIP revisions and periodic progress reports describing progress towards the RPGs; commitment to make a determination of the adequacy of the existing SIP at the time a progress report is submitted; and consultation and coordination with federal land managers (FLMs).
EPA partially approved and partially disapproved portions of other core elements of the SIP including: identification of best available retrofit technology (BART) eligible sources and subject to BART sources; requirements for BART; Chapter 15 of the Air Pollution Control and Ecology Commission (APCEC) Regulation No. 19, also known as the State’s RH Rule; and the LTS. EPA disapproved Arkansas’s reasonable progress goals (RPGs) under section 110 and part C of the CAA.
EPA said it agreed with Arkansas’s identification of sources that are BART eligible, with the exception of the 6A Boiler at the Georgia-Pacific Crossett Mill, which EPA found to be BART eligible. EPA also agreed with Arkansas’s identification of subject to BART sources, with the exception of the 6A and 9A Boilers at the Georgia-Pacific Crossett Mill, which EPA found to be subject to BART.
EPA was not able to approve the following BART determinations made by Arkansas: the SO2, NOx, and particulate matter (PM) BART determinations for the Arkansas Electric Cooperative Corp. (AECC) Bailey plant Unit 1 and the AECC McClellan plant Unit 1; the SO2 and NOx BART determinations for AEP Flint Creek Boiler No. 1; the NOx BART determination for the natural gas firing scenario and the SO2, NOx, and PM BART determinations for the fuel oil firing scenario for the Entergy Corp. (NYSE:ETR) Lake Catherine plant Unit 4; the SO2 and NOx BART determinations for both the bituminous and sub-bituminous coal firing scenarios for the Entergy White Bluff Units 1 and 2; the BART determination for the Entergy White Bluff Auxiliary Boiler; the SO2 and NOx BART determinations for the Domtar Ashdown Mill Power Boiler No. 1; and the SO2, NOx and PM BART determinations for the Domtar Ashdown Mill Power Boiler No. 2.
“In reviewing the state’s BART determinations for these pollutants and units, we found that the state did not satisfy all the regulatory and statutory requirements in making these BART determinations,” said EPA. “We have therefore determined it is appropriate to finalize our proposed disapproval of the state’s BART determinations for these units, because we conclude that the flaws and omissions in the state’s BART analyses were significant, and that the state therefore lacked adequate record support and a reasoned basis for its analyses, as required by the RH Rule (RHR).”
EPA approved the portion of the BART compliance provision that requires each Arkansas subject to BART source to install and operate BART as expeditiously as practicable, but in no event later than five years after EPA approval of the Arkansas RH SIP, for those sources’ BART determinations it is approving.
EPA also partially approved and partially disapproved the state’s submitted LTS because it relies on portions of the RH SIP that the agency disapproved, including some of Arkansas’s BART emission limits. It disapproved the state’s RPGs because Arkansas did not consider the four factors that states are required to consider in establishing RPGs.
EPA did approve parts of the SIP, including: the PM BART determination for the AEP Flint Creek Plant Boiler No. 1; the SO2 and PM BART determinations for the natural gas firing scenario for the Entergy Lake Catherine Plant Unit 4; the PM BART determinations for both the bituminous and sub-bituminous coal firing scenarios for the Entergy White Bluff Plant Units 1 and 2; and the PM BART determination for the Domtar Ashdown Mill Power Boiler No. 1.
EPA agrees and disagrees with some outside commenters
In the 74-page Federal Register notice, EPA addressed comments lodged by a number of parties related to specific power plant emissions. For example, one unnamed commenter said that EPA had previously pointed out that Entergy White Bluff did not evaluate the most stringent level of control achievable in that it did not evaluate emission limits lower than the presumptive SO2 BART emission limit of 0.15 lb/MMBtu for either a wet or a dry scrubber. The commenter said that EPA did not mention that both wet and dry scrubbers can achieve greater than the control efficiencies assumed in the White Bluff analysis (i.e. greater than 95% control with a wet scrubber, and greater than 92% control with a dry scrubber). EPA had previously pointed out that SO2 emission rates as low as 0.065 lb/MMBtu have been documented with installation of dry scrubbers.
The commenter also pointed out that EPA recently proposed a Federal Implementation Plant (FIP) requiring the installation of dry scrubbers as BART at six coal-fired electric generating units in Oklahoma, to achieve the SO2 BART emission limit of 0.06 lb/MMBtu on a 30-day rolling average basis. These units burn similar low-sulfur coal as that primarily burned at the Entergy White Bluff Units 1 and 2. A limit of 0.06–0.065 lb/MMBtu would reflect 92.2% to 92.8% removal from the highest SO2 rate identified by Entergy during the base case of 0.83 lb/MMBtu, the commenter said. Therefore, SO2 emission rates much lower than 0.15 lb/MMBtu should be achievable with the installation of a wet scrubber or a dry scrubber/baghouse at White Bluff Units 1 and 2. Wet scrubbers can achieve 98–99% SO2 removal and dry scrubbers can achieve 95% SO2 removal. An October 2008 Sargent & Lundy study of SO2 control technologies for White Bluff makes clear that dry scrubbers are capable of 95% removal efficiency, and wet scrubbers are capable of 95–99% removal efficiency, the commenter said. This study also indicates that the typical Powder River Basin coal SO2 emission rates expected from wet scrubbers ranges from 0.03 to 0.10 lb/MMBtu, and for dry scrubbers ranges from 0.06 to 0.12 lb/MMBtu. Therefore, the commenter said that EPA should require consideration of emission limits more stringent than ADEQ’s proposed SO2 BART limit of 0.15 lb/MMBtu.
“The EPA agrees that wet scrubbers for control of SO2 emissions have been demonstrated to achieve as high as 98–99% removal efficiency, while dry scrubbers have been demonstrated to achieve as high as 95% removal efficiency,” said the EPA response. “SO2 emission rates much lower than 0.15 lbs/MMBtu are achievable at Entergy White Bluff Units 1 and 2 with the installation of a wet or dry scrubber. This is consistent with our proposed rulemaking on the Arkansas RH SIP, in which we noted that the 0.15lb/MMBtu presumptive SO2 limit the state established for both the bituminous and sub-bituminous coal firing scenarios for White Bluff Units 1 and 2 corresponds to 82% control removal of the wet scrubber at Unit 1 and 80% control removal of the wet scrubber at Unit 2, while such controls are capable of a higher control efficiency. EPA’s proposed rulemaking proposed to disapprove the state’s determination that SO2 BART for White Bluff Units 1 and 2 is the presumptive limit of 0.15 lb/MMBtu for both the sub-bituminous and bituminous coal firing scenarios, as the state is required to evaluate the cost and visibility impact of operating controls at the maximum control efficiency achievable (i.e. to achieve the most stringent emission limit capable of being achieved by those controls).”
EPA action on Arkansas SIP has a long history
Entergy addressed EPA’s proposed version of the partial SIP disapproval in its Feb. 28 Form 10-K report. “In June 2005, the EPA issued final Best Available Retrofit Control Technology (BART) regulations that could potentially result in a requirement to install SO2 and NOx pollution control technology on certain of Entergy’s coal and oil generation units,” said the Form 10-K. “The rule leaves certain BART determinations to the states. The Arkansas Department of Environmental Quality (ADEQ) prepared a State Implementation Plan (SIP) for Arkansas facilities to implement its obligations under the Clean Air Visibility Rule. The ADEQ determined that Entergy Arkansas’s White Bluff power plant affects a Class I Area’s visibility and will be subject to the EPA’s presumptive BART limits, which likely would require the installation of scrubbers and low NOx burners. Under then-current state regulations, the scrubbers would have had to be operational by October 2013.”
The Form 10-K noted that Entergy Arkansas filed a petition in December 2009 with the Arkansas Pollution Control and Ecology Commission requesting a variance from this deadline, however, because the EPA had expressed concerns about Arkansas’s Regional Haze SIP and questioned the appropriateness of issuing an air permit prior to that approval. Entergy Arkansas’s petition requested that, consistent with federal law, the compliance deadline be changed to as expeditiously as practicable, but in no event later than five years after EPA approval of the Arkansas Regional Haze SIP. The Arkansas commission approved the variance in March 2010.
“In October 2011 the EPA released a proposed rule addressing the Arkansas Regional Haze SIP,” the Form 10-K added. “In the proposal the EPA disapproves a large portion of the Arkansas Regional Haze SIP, including the emission limits for NOx and SO2 at White Bluff. The EPA did not issue a Federal Implementation Plan for regional haze requirements because Arkansas has indicated it wishes to correct its SIP and resubmit it. Due to an extension in the comment period for the proposed rule, EPA has yet to issue a final rule. It is expected that after the EPA’s proposed rule becomes final, there will be a two-year timeframe in which the EPA must either approve a SIP issued by Arkansas or issue a Federal Implementation Plan.”