Environment

Louisville Gas & Electric has reached an agreement with the city’s air pollution regulators to reduce emissions that contribute to harmful ground level ozone during the warmest months of the year. 

Jefferson and surrounding counties have been out of compliance with acceptable levels of ground level ozone since 2018 when the Environmental Protection Agency designated them as “nonattainment” areas for the harmful pollutant, which can aggravate airways and increase the frequency of asthma attacks. 

To reduce ground level ozone, Louisville’s Air Pollution Control District reached an agreement with LG&E that states the power company will limit emissions of nitrogen oxides (NOx) from the Mill Creek coal-fired power plant between May 9 and Oct. 31.   

Ground level ozone forms when NOx and volatile organic compounds (VOCs) react in the presence of sunlight. The hotter and drier it is, the more ozone is created. Louisville’s ozone season runs from March through October. 

APCD interim director Rachael Hamilton said this is the second year that LG&E has voluntarily agreed to reduce emissions to limit the formation of ground level ozone.

“We had some ozone exceedances last year. The area is at a 72 parts per billion (ppb) standard above a 70 parts per billion standard,” Hamilton said. “Our goal is to bring the area into attainment with that standard this year. This will help to do that.”

LG&E’s Mill Creek power plant is the largest single source of NOx in the Louisville Metropolitan Statistical Area (MSA), which includes Jefferson, Bullitt and Oldham counties in Kentucky and Clark and Floyd counties in Indiana.

The power company has agreed to limit emissions at the coal-fired Mill Creek plant to 15 tons of NOx or less per day, though there are exceptions. 

LG&E spokesperson Chris Whelan said the plant will reduce running the generators at Mill Creek Units 1 and 2 and will instead shift load to other units within the fleet. Whelan said LG&E is currently meeting regulatory requirements for air quality but agreed to more modifications with APCD to help improve ozone levels this year. 

“We’re agreeing to make these modifications at Mill Creek to help our community and to assist Jefferson County and the immediate surrounding areas meet the U.S. EPA’s standards for ozone,” Whelan said in an email. 

APCD is currently accepting public comments and will hold a video conference next Wednesday at 10 a.m., during which the board is expected to vote in favor of the agreement. Information and instructions to attend the conference are available at this link.

Ryan Van Velzer is WFPL's Energy and Environment Reporter.