West Lafayette, Indiana - A Purdue University climate adaptation expert can speak on the consequences of a new Environmental Protection Agency regulation that gives states more leeway to improve the efficiency of coal plants and set their own greenhouse gas emission limits.

"New policies extending the life of coal might encourage states to fire biomass with coal," says David Johnson, assistant professor of industrial engineering and political science. "You can get anywhere from 5 to 20 percent of your energy content at a coal plant through co-firing biomass without having to make really extensive changes to your equipment or to your boiler systems."

Midwest states heavily dependent on coal production might be especially more inclined to adopt bioenergy under these rollbacks.

Biomass - such as corn stover, switch grass, or energy crops like poplar or willow – could be used to reduce carbon emissions at coal plants, Johnson says, but the extent and cost of that benefit would depend on the source of the biomass and the policies a state puts in place.

Johnson's research on feedback loops in food, energy and water systems has shown that when sourcing biomass leads to converting more land use to agriculture, this could mean more fertilizer use, which can increase nitrogen leeching issues and exacerbate the "dead zone" in the Gulf of Mexico from hypoxia.

"A greater promotion of bioenergy has spillover effects into the food and water systems," Johnson says. "On the other hand, using biomass as a substitute for coal could mean reducing greenhouse gas emissions to some extent since it's cleaner."

Johnson can also speak on the benefit-cost analysis and economics associated with adapting to climate change, in relation to the EPA's claim that rescinding the President Barack Obama-era Clean Power Plan would save $33 billion.

"The EPA's new analysis does not consider impacts of climate change from U.S. emissions on other parts of the world, and how that then turns around and impacts the U.S., through migration induced by climate extremes, changes in energy or food prices, or through retributory economic actions taken by other countries to punish the U.S. for its policy stances," Johnson says.