House Republicans are gearing up for a fight against Obama administration plans to counter climate change through increased regulation.

Rep. Ed Whitfield (R-Ky.), the chairman of the House Energy and Power subcommittee, warned Tuesday that any attempt by the Environmental Protection Agency (EPA) to impose new emission standards for existing power plants would meet fierce opposition. Already the agency has put forward rules to control emissions at new power plants.

“The Environmental Protection Agency has been overly zealous,” Whitfield said during remarks at the National Association of Regulatory Utility Commissioners’ (NARUC) winter meeting.

“If they start trying to do this with existing plants, they’re going to have a real battle,” he told reporters afterward.