Rick Perry Is Said to Be Resigning as Energy Secretary by Year’s End

Mr. Riddlesperger said Mr. Perry’s relatively successful run in the Trump administration underscored the value of experience. “He’s one of the very few mainstream political appointments that President Trump made,” he said, “and I think it’s not surprising that he fared better than some people who don’t have that political experience.”

An Air Force veteran and graduate of Texas A&M University with a degree in animal science, Mr. Perry came to the agency charged with overseeing United States nuclear weapons programs, national laboratories and vast energy research programs without the academic pedigree or scientific background of his immediate predecessors.

He also arrived having called for the elimination of the agency as part of his failed 2012 presidential campaign — yet famously forgetting the agency’s name during a Republican primary debate the previous year. In that debate, Mr. Perry said he would eliminate three cabinet-level departments, including the Departments of Commerce and Education — and a third one that he could not remember. “I can’t, the third one, sorry. Oops,” he said.

In his confirmation hearing before the Senate, Mr. Perry apologetically walked back that pledge. However, he continued to stand firm on another position: his dismissal of the established scientific evidence that human-caused emissions are responsible for the Earth’s record warming.

Mr. Perry has repeatedly questioned whether, and by how much, man-made greenhouse gas pollution from tailpipes, smokestacks and other sources drives climate change. He has also aggressively promoted fossil fuels, despite the fact that wind energy expanded significantly in Texas while he was governor.

Senator Edward J. Markey, Democrat of Massachusetts and an outspoken advocate for tackling climate change, criticized Mr. Perry for favoring fossil fuels and nuclear power over energy options like solar and wind, which Mr. Markey said were more competitive in the marketplace. “He’s almost the perfect embodiment of the rearview thinking of the Republican Party on our energy future,” Mr. Markey said.

Mr. Perry has counted gains in exporting coal and liquefied natural gas among his accomplishments as energy secretary. He also poured $3.7 billion in federal loan guarantees into a struggling nuclear power project in Georgia.

And while a plan to bail out ailing coal and nuclear plants failed, promoting those energy sources has remained a favored talking point. In April the Energy Department issued a “Game of Thrones”-themed video in which Mr. Perry declared, “A new American energy era is coming.”

For more news on climate and the environment, follow @NYTClimate on Twitter.