EPA seeks input on how to reduce GHGs at natural gas fired EGUs

The U.S. EPA on April 21 announced it is seeking public comments on a draft technical white paper focused on ways to reduce greenhouse gas (GHG) emissions from new natural gas-fired turbines. The paper, in part, considers the use of alternative fuels, including biogas and renewable natural gas (RNG).

According to the EPA, new stationary combustion turbines—primarily fueled with natural gas—are currently projected to be a significant part of U.S. electricity generation in future years. The agency said that release of the draft white paper for public comment is one step forward in its efforts to engage communities and the power sector on strategies to improve clean air and reduce climate pollution in the years ahead.

“As part of our comprehensive power sector strategy announced by Administrator Regan last month, this white paper is intended to advance EPA’s work to cut greenhouse gas emissions and amplify the leadership that we are seeing from power companies, states, investors, communities and other organizations,” said Principal Deputy Assistant Administrator for Air and Radiation Joseph Goffman. “This is an important dialogue to have now, as we tackle our climate and health goals to protect communities while ensuring clean, reliable and affordable electricity.”

The white paper does not set policy or standards or establish any binding requirements under any particular regulatory program. Rather, the EPA said it anticipates public dialogue on the draft will help inform consideration of a Clean Air Act section 111 standard for new natural gas electric utility generating units (EGUs). In addition, the agency said the discussion of technologies and measures in the paper may also provide context for permit development under the prevention of significant deterioration (PSD) program of the CAA, including the assessment of the best available control technology (BACT) for GHG emissions from stationary combustion turbines.

The 65-page white paper addresses a wide range of issues, including those related to GHG control approaches for combustion turbine EGUs related to efficiency and design improvements. It also includes a discussion of the GHG impact of various fuels that be burned in combustion turbine EGUs, including biogas and RNG, coal mine methane, methane emissions from abandoned oil and gas wells, industrial byproduct fuels, and others.

According to the white paper, most of the GHG benefits associated with the use of bigas and RNG come from upstream reductions through the capture and beneficial use of methane that would have otherwise been emitted to the atmosphere, including biobased methane generated via landfills, the agricultural sector and wastewater management.

The paper cites federal data that shows there is significant potential for expanded biogas and RNG production in the U.S. In the paper, the EPA estimates that methane emissions from U.S. landfills were at 114.5 million metric tons of carbon dioxide equivalent in 2019, accounting for 17 percent of total U.S. methane emissions. As of September 2021, approximately 20 percent of municipal solid waste (MSW) landfills provided landfill gas-to-energy projects, according to EPA. The agency estimates that an additional 20 percent of MSW landfills could economically recover their landfill gas for useful purpose.

For the ag sector, the paper estimates that livestock GHG emissions were 260.6 million metric tons of carbon dioxide equivalent in 2019. The USDA AgSTAR program estimates that there are currently more than 300 dairy and swine anaerobic digester biogas recovery systems in the U.S., with an additional 8,100 operations that could support such systems. New technologies may also make biogas systems feasible at poultry and beef lot operations, according to the EPA.

In addition, the EPA estimates that the U.S. is home to more than 16,000 wastewater treatment plants. Only about 1,300 of those facilities use anaerobic digestion to produce biogas. The agency estimates that in 2019 wastewater from these treatment facilities emitted 18.4 million metric tons of carbon dioxide equivalent methane in the U.S.

The public comment period on the white paper is open through June 6. A full copy of the white paper and directions on how to submit comments is available on the EPA website.