EPA proposes approval of variances to Illinois air program for Midwest Gen coal plants

The U.S. Environmental Protection Agency is proposing to approve into the Illinois regional haze State Implementation Plan (SIP) variances affecting several coal-fired plants in Illinois of Midwest Generation LLC.

Those facilities are: Crawford Generating Station (Cook County), Joliet Generating Station (Will County), Powerton Generating Station (Tazewell County), Waukegan Generating Station (Lake County), and Will County Generating Station (Will County). The Illinois Environmental Protection Agency (IEPA) submitted these variances to EPA for approval in May 2013 and August 2014. Comments must be received within 30 days after publication of the proposed decision in the April 23 Federal Register.

The U.S. EPA’s  Regional Haze Rule allows states to meet best available retrofit technology (BART) requirements by mandating alternative measures in lieu of mandating source-specific BART, so long as the alternative measures provide better visibility protection. Given the regional nature of visibility impairment, an alternative that results in lower emissions of SO2 and NOX will generally provide better visibility protection. Thus, in the absence of a difference in the spatial distribution of emissions, a modeling analysis is generally not necessary to be able to conclude that an alternative strategy with lower SO2 and NOX emissions provides better visibility protection.

In June 2011, Illinois submitted a plan to address the requirements of the Regional Haze Rule. EPA approved Illinois’ regional haze SIP in July 2012. In its approval, EPA determined that the emission reductions from sources included in the Illinois plan are significantly greater than even conservative definitions of BART applied to BART subject units. EPA also addressed whether the Illinois plan, achieving greater emission reductions overall than the application of BART on BART-subject units, can also be expected to achieve greater visibility protection than application of BART on BART-subject units. These plants are subject to the state’s Combined Pollutant Standard (CPS), which mandates strict emissions cuts that can apply against the Regional Haze reduction needs.

The CPS requires Midwest Generation to install and have operational a flue gas desulfurization (FGD) system on Unit 7 of the Waukegan Generation Station or shut down the unit on or before Dec. 31, 2013. It requires that Midwest Generation replace the hot-side electrostatic precipitator (ESP) on Unit 7 at the Waukegan Generation Station with a cold-side ESP, install an appropriately designed fabric filter, or permanently shut down the unit on or before Dec. 31, 2013. The CPS also requires Midwest Generation to install and have operational a FGD system on Unit 8 at Waukegan or shut down the unit by Dec. 31, 2014.

The Illinois Pollution Control Board (IPCB) granted Midwest Generation variances to parts of the CPS in August 2012 and April 2013. These variances are the subject of the U.S. EPA’s proposed approval.

The variances granted by the IPCB and submitted by IEPA for approval change the requirements for Midwest Generation under the regional haze SIP included:

  • The IPCB granted Midwest Generation a variance from the average annual SO2 emission rates of 0.28 pounds per million Btu (lb/mmBtu) in 2015 and 0.195 lb/mmBtu in 2016, subject to numerous conditions.
  • The IPCB granted Midwest Generation a variance from the Dec. 31, 2013, deadline for installation and operation of control equipment on Unit 7 of the Waukegan Generation Station subject to the condition that Midwest Generation must either install the required pollution controls or permanently shut down Unit 7 at the Waukegan Generating Station on or before Dec. 31, 2014.
  • The IPCB granted Midwest Generation a variance from the Dec. 31, 2014 deadline for installation and operation of FGD equipment on Unit 8 at Waukegan subject to, among other things, the following condition: Midwest  Generation must install the required pollution controls or permanently shut down Unit 8 at Waukegan by May 31, 2015. Midwest Generation is not allowed to operate Waukegan Unit 8 from Jan. 1, 2015, until completion of the installation of FGD equipment.
  • In addition to the conditions described above, the variances granted by the IPCB are subject to a number of other conditions including, but not limited to: Midwest Generation must shut down the coal-fired unit at Fisk Generation Station on or before Dec. 31, 2012; it must cease operation of the coal-fired units at the Crawford Generating Station by April 4, 2013, and shut down the units on or before Dec. 31, 2014; it must install and have operational FGD equipment and related ESP upgrades at Powerton Unit 6 by Dec. 31, 2014; it must limit annual system-wide mass emissions of SO2 to no more than 57,000 tons in 2013, 54,000 tons in 2014, 39,000 tons in 2015, and 37,000 tons in 2016.

Midwest Generation ceased operation of the coal-fired boiler at Fisk in August 2012, four months earlier than was required by the variance. Midwest Generation ceased operation at Crawford in August 2012, seven months earlier than was required by the variance.

Under the conditions of the currently approved regional haze SIP, the Midwest Generation CPS group would be expected to emit 190,181 tons of SO2 for the 2013-2016 time period. Under the variances, these plants would be expected to emit 185,599 tons of SO2 over that same time period; 4,582 tons fewer than would be expected under the current SIP. Further, because Midwest Generation ceased operation at Fisk and Crawford in August 2012, there were 1,983 tons of SO2 emissions reductions (734 tons at Fisk and 1,249 tons at Crawford) realized in 2012 that were not required by the SIP and an additional 8,563 tons of SO2 emissions reductions from Crawford beyond what was required in the SIP for the 2017-2018 time period. Over the entire 2012-2018 time period it is estimated that the variances result in 15,129 tons fewer SO2 emissions than were expected under the regional haze SIP.

The variances will not result in an increase in SO2 or particulate matter (PM) emissions, but rather will result in lower SO2 and PM emissions overall and in 2017, the year that BART is required to be implemented in Illinois. In addition, reductions in NOX, mercury, and greenhouse gasses can also be attributed to the variances. Therefore, the variances will not interfere with attainment, reasonable further progress, or any other applicable requirement of the Clean Air Act, said EPA in the April 23 notice.

NRG Energy (NYSE: NRG), which owns Midwest Generation, has said that it intends to add natural gas burning capability to Units 6, 7 and 8 of the Joliet coal facility no later than June 2016. It earlier in April deactivated Will County Unit 3. It is adding in the 2014-2016 period dry sorbent injection for SO2 control at Powerton 5-6 and Waukegan 7-8.

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.