This week, the Environmental Protection Agency announced its proposed rule to regulate greenhouse gas emissions (GHG) from power plants. Power plants account for a quarter of all U.S. GHG emissions and is the largest stationary source of such pollutants.

The rule EPA proposed has three main components:

New Power Plants – the proposed rule creates GHG emissions standard for new power plants.

Existing Power Plants – the proposed rule creates GHG emission standards for existing coal, oil-fired power plants and a different set of GHG emissions standard for existing gas-fired power plants. In general, existing power plants will either need to adopt new GHG emissions control technology or plan to retire in the near future.

State Guidance – While proposed rules for existing power plants are applied to specific facilities, it is the obligation of states to develop statewide plans for their existing power plants to come into compliance with the federal standards. The third component of the rule provides guidance to states on how to ensure their power plants come into compliance with the proposed federal GHG emission standards.

Electric power generation is the second largest source of GHG emissions in the U.S., comprising 25 percent of total U.S. GHG emissions. The transportation sector is the leading source of U.S. GHG emissions, emitting 28 percent total U.S. GHG emissions. The EPA has already proposed rules to reduce vehicle tailpipe GHG emission from cars and light trucks for model years 2027, and in a separate rule has proposed to reduce GHG emissions from heavy duty trucks.

Like previous EPA rules to regulate GHG emissions from power plants, it is expected that these proposed rules will be challenged in court by the fossil fuel industry and states that have coal industry ties. In issuing the proposed rule, the EPA noted that the agency closely reviewed U.S. Supreme Court decisions and based the proposal on clearly established authorities of the Clean Air Act.

“We believe the EPA has carefully considered previous U.S. Supreme Court decisions and crafted a regulatory strategy that will address climate change by making significant reductions in GHG emission from power plants while simultaneously withstanding judicial scrutiny,” said Jack Harkema, DVM, PhD, chair of the ATS Environmental Health Policy Committee.

“This is big!” said ATS Environmental Health Policy Committee Vice Chair Alison Lee, MD. “Today’s GHG power plant ruling, combined with the EPA’s proposed rules to reduce GHG emissions from cars and trucks, as well as methane emissions from fossil fuel extraction, are major steps towards addressing climate change.”