President-elect Donald Trump on Saturday selected Liberty Energy CEO Chris Wright to serve as the next energy secretary of the United States.

Liberty Energy is an oilfield services company headquartered in Denver with a $2.7 billion market capitalization. The company’s stock gained nearly 9% on Nov. 6 after Trump won the U.S. presidential election, but its shares have since pulled back.

Wright serves on the board of Oklo, a nuclear power startup backed by OpenAI CEO Sam Altman that is developing micro reactors.

Wright will also serve on Trump’s Council of National Energy, the president-elect said Saturday. The council will be led by Trump’s pick for Interior Secretary, North Dakota Gov. Doug Burgum.

Wright has denied that climate change presents a global crisis that needs to be addressed through a transition away from fossil fuels.

“There is no climate crisis and we’re not in the midst of an energy transition either,” Wright said in a video posted on his LinkedIn page last year. “Humans and all complex life on earth is simply impossible without carbon dioxide. Hence the term carbon pollution is outrageous.”

“There is no such thing as clean energy or dirty energy,” Wright said. “All energy sources have impacts on the world both positive and negative.”

Trump described Wright as a “leading technologist and entrepreneur in the energy sector.”

“He has worked in Nuclear, Solar, Geothermal, and Oil and Gas,” the president-elect said in a statement Saturday.

“Most significantly, Chris was one of the pioneers who helped launch the American Shale Revolution that fueled American Energy Independence, and transformed the Global Energy Markets and Geopolitics,” Trump said.

Trump has vowed to increase fossil fuel production to reduce energy costs, though analysts and some oil executives have said the president has little influence on oil and natural gas output in the U.S.

The U.S. has produced more crude oil than any other country in history, including Russia and Saudi Arabia, since 2018, according to the Energy Information Administration.