WASHINGTON —U.S. Energy Secretary Steven Chu, who won a Nobel Prize in physics but came under questioning for his handling of a solar energy loan, is stepping down and a Baton Rouge businessman may be up for the post.

Chu offered his resignation to President Barack Obama in a letter Friday. He said he would stay on at the Department of Energy at least until the end of February and may stay until a successor is confirmed.

Jim Bernhard, founder of The Shaw Group Inc., of Baton Rouge, said he is in the running to replace Chu, WBRZ-TV reported Friday. Bernhard did not return two calls from The Advocate seeking comment.

Bernhard said several others also are being considered, according to WBRZ. Bernhard recently sold Shaw to Texas-based CB&I for more than $3 billion.

White House spokeswoman Joanna Rosholm declined to comment about Bernhard, except to say there are no new personnel announcements to make regarding the energy secretary. A White House news release of Obama’s priorities would remain unchanged.

Sen. Mary Landrieu, D-La., said in an email response that Bernhard would make a great choice. “Jim Bernhard is an industrialist and an environmentalist who has dedicated his life to being a responsible steward of our natural resources,” Landrieu stated.

Don Briggs, president of the Louisiana Oil and Gas Association, a trade group, also endorsed the selection of Bernhard. “He understands the energy business and he comes from an energy state.”

The Energy Department oversees energy, environmental and nuclear issues for the federal government.

Rep. Steve Scalise, R-Jefferson, said he has heard Bernhard’s name mentioned as a potential candidate to replace Chu. But Scalise said he does not know whether Bernhard is being considered within a pool of “two or 20” contenders.

Scalise said Bernhard would represent a big improvement over Chu, whom he called “one of the worst energy secretaries ever.”

“Jim Bernhard is pro-energy and he’d be one of the few in the Obama industry with real-world experience in creating jobs,” Scalise said.

The departure of Chu, the 64-year-old former director of the Lawrence Berkeley National Lab in California, had been widely expected and follows announcements by Interior Secretary Ken Salazar, Environmental Protection Agency chief Lisa Jackson and Jane Lubchenco, head of the National Oceanic and Atmospheric Administration, that they are leaving.

Obama said in a statement Friday that Chu brought a “unique understanding of both the urgent challenge presented by climate change and the tremendous opportunity that clean energy represents for our economy.”

During his tenure, Chu helped move the country toward energy independence, Obama said, referring to billions of dollars in Energy Department loans to boost renewable energy such as wind and solar power.

“Thanks to Steve, we also expanded support for our brightest engineers and entrepreneurs as they pursue groundbreaking innovations that could transform our energy future,” Obama said.

In a letter to Energy Department employees, Chu said he was proud of his tenure and cited dozens of accomplishments, including doubling the production of renewable energy from wind and solar power. Installations of solar electric systems have nearly doubled in each of the last three years, he said, while fully 42 percent of new energy capacity in the U.S. last year was from wind — more than any other energy source.

“I came with dreams and am leaving with a set of accomplishments that we should all be proud of,” he said.

One of his accomplishments was something that Chu rarely talked about, but was frequently cited by Obama: Chu’s role in helping to plug the massive BP oil leak in the Gulf of Mexico. Chu and a team of engineers helped devised an interim solution before a replacement well permanently plugged the leak, which spewed more than 200 million gallons of oil in the worst offshore oil disaster in the country’s history.

Chu came up with the solution “when nobody else could figure it out,” Obama said Friday. “And that’s typical of the incredible contributions that he’s made to this country.”

Mark Ballard and Michelle Millhollon of The Advocate Capitol news bureau and Matthew Daly of The Associated Press contributed to this report.