The White House is seeking replacements for Ron Binz, President Obama's nominee to lead the Federal Energy Regulatory Commission, a Democratic senator said on Thursday.

“I think he’s gone,” Senator Joe Manchin, D-W. Va., said at a breakfast organized by Bloomberg Government.

Manchin said Democratic lawmakers were told this week that the White House was vetting other candidates for the position.

White House press secretary Jay Carney publicly stood behind Binz, who has come under fire for controversial statements about the role of government regulators and the nation's transition to renewable energy sources.

Binz once called natural gas a "dead end."

Carney did not specifically respond to Manchin's claims, saying the full Senate should still confirm Binz.

When Manchin came out against Binz in recent days, however, Democrats no longer had the votes to move the nomination out of the Senate Energy and Natural Resources Committee.

FERC, an independent commission of five members, regulates the interstate transmission of natural gas, oil and electricity; handles proposals to build natural gas pipelines; and does licensing for hydropower projects.

The normally routine confirmation process is now part of a broader proxy fight over Obama's ambitious green-energy agenda. The Environmental Protection Agency recently rolled out the first-ever proposed carbon limits on future power plants, which Republicans dismissed as a "war on coal."