Ameren to begin burning gas this month at two Meramec coal units

Ameren Missouri’s coal-fired Rush Island and Sioux plants were compliant with the federal Mercury and Air Toxics Standards (MATS) as of the April 16, 2015, original compliance deadline, with the coal-fired Labadie and Meramec (units 3 & 4) plants receiving a one-year extension and will be compliant on April 16, 2016.

The utility noted in an integrated resource plan (IRP) update filed with the Missouri Public Service Commission on April 12 that Units 1 & 2 at Meramec will as of this month begin limited burning of natural gas and will not be subject to MATS. Ameren Missouri installed Activated Carbon Injection technologies and/or fuel additives and other sorbents to control mercury emissions at all four of its coal-fueled energy centers and made modifications to the existing PM controls at its Labadie plant. In addition, Ameren Missouri will utilize work practices and fuel choices to meet the other MATS-regulated hazardous air pollutants.

Electrostatic precipitator upgrades on Labadie Units 1 & 2 to comply with MATS have been completed, and the Unit 4 ESP upgrade is currently on schedule for completion in spring 2016. Ameren Missouri determined through its testing of the upgraded precipitators on Units 1 & 2 that the previously planned upgrade of the Unit 3 ESP can be delayed.

While several outcomes are possible, Ameren Missouri believes the most likely requirement from any future attainment plans will be the need to install selective catalytic reduction (SCR) at Sioux. This is primarily due to the very low NOx emission rates at the Labadie and Rush Island centers and the planned retirement of Meramec by the end of 2022.

The Coal Combustion Residuals (CCR) rule was published by the U.S. EPA in April 2015 and became effective last October 19. It establishes national standards for the management of CCRs. Historically, coal ash has typically been wet sluiced into ash ponds. Ash ponds are permitted as wastewater treatment devices under the Missouri water permit program and are subject to closure requirements when they are excluded from the water permit process. Ash pond closures may require an evaluation of groundwater conditions and the development of a closure plan that includes an impervious cap and vegetative cover. Long-term monitoring of groundwater conditions and the integrity of the cap and vegetation may be required.

In response to the CCR rules and the Effluent Limitation Guidelines, Ameren Missouri is planning the following projects for its energy centers:

Labadie Energy Center

  • Complete the construction and operation of the on-site landfill
  • Dry ash conversion projects will be implemented
  • Close the bottom and fly ash ponds
  • New wastewater treatment facilities will be installed

Meramec Energy Center

  • Begin the closure of some of the ponds except for those necessary for operation until retirement when the remaining ponds will be closed
  • Off-site reuse or disposal options will be established as needed

Rush Island Energy Center

  • Dry ash conversion projects will be implemented
  • Close the bottom and fly ash ponds
  • New wastewater treatment facilities will be installed
  • Off-site reuse or disposal options will be established

Sioux Energy Center

  • Continue the operation of the on-site landfill
  • Dry ash conversion projects will be implemented
  • Close the bottom and fly ash ponds
  • New wastewater treatment facilities will be installed
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.