The last remaining Republican to serve on the nation's grid watchdog in the waning months of the Obama administration announced he will step down next month.

Federal Energy Regulatory Commissioner Tony Clark took to Twitter late last week to announce that he will leave the independent agency that oversees the nation's wholesale electricity and natural gas system on Sept. 22.

"After four-plus years on FERC, I'm announcing today that the September Commission meeting will be my last," Clark said.

His term officially ended June 30, but he had not said exactly when he would be departing. Clark told the Washington Examiner in May that he is allowed to stay on until the president appoints a new Republican to the commission, but the White House has been slow to do so.

President Obama, who appoints the commissioners, has been mum on new Republicans joining the commission since long-time commissioner Phil Moeller left in October, leaving Clark to be the sole Republican alongside his two Democratic colleagues and the chairman.

FERC's five-member panel is supposed to be composed of equal numbers Republicans and Democrats, with the chairman being from the party of whomever is in the Oval Office.

"Since June 30 I've been serving in an expired term (as allowed by law) and had previously announced I wouldn't request reappointment," Clark tweeted. "Public service has been an honor, but these aren't meant to be forever jobs. Looking forward to next chapter, whatever that may be."

Clark told the Examiner that he hasn't decided what he would do after he leaves the commission. He said that he is interested in the intersection between the electricity and telecommunication sectors and that might be an area of focus in the future.

The commission has become a huge target for environmental groups that have targeted it as a supporter of the fossil fuel industry based on its approval of natural gas pipelines and liquefied natural gas export facilities.

The activists say the pipelines and LNG terminals increase oil and gas production from fracking, which in turn heats the Earth's atmosphere, causing global warming and climate change.