As energy chief, Ernest Moniz is man in the middle

But hidden behind the wonky demeanor one would expect from Moniz, a former MIT professor who got hooked on physics at Durfee High School in Fall River, is a measure of political savvy earned as a veteran of the Clinton administration. It is a well of experience that his supporters say will help him lead key initiatives in President Obama’s second term — including an expansion of America’s nuclear power industry.

At a time when the White House plans to exercise greater executive authority to circumvent a recalcitrant Congress, Moniz, 69, is in charge of one of the most controversial portfolios in the Cabinet, requiring him to balance worries about global warming with the demands of a powerful energy industry.

Constituencies clamoring for his favor include gas and oil companies that want permission to drill and export more; clean energy start-ups eager for more government loans; environmentalists, some of them critical of Moniz’s ties to industry, who want a stronger emphasis on wind and solar energies; and scientists seeking more research money.

In a wide-ranging interview as he traveled around the Virginia coast — touring a federal laboratory and giving a speech at Hampton University — Moniz, who was confirmed 97 to 0 by the Senate in May, discussed the administration’s “all-of-the-above” energy philosophy.

He previewed plans to increase energy efficiency standards. And he said he planned to move forward aggressively on more government loans to private energy companies, despite the embarrassing bankruptcy filings of Solyndra and A123 Systems of Waltham.

”We’ve got a big-time problem to address climate,” he said, riding in the back of a sport utility vehicle. “And if it’s business as usual, we’re not going to get there in time.”

The opera-loving fly-fisherman also divulged details about his hair, which has generated intense interest on Twitter, triggered photo galleries online, and drawn comparisons to, among others, George Washington.

“No one except my wife has cut my hair in decades. And she’s not a professional,” he said. “It’s a big joke, and that’s OK.”

“If it gets people interested in the Department of Energy,” he added with a laugh, “it’s good.”

Moniz was born in Fall River, where his father worked at Firestone, the rubber manufacturing plant, and his mother watched after him, the only child. All four of his grandparents were emigrants from the Azores Islands.

“I came from a blue-collar town, a public school,’’ he told students at Hampton University. “It’s a great country to be able to do this.”

He played baseball and tennis at Durfee. He also benefited from an MIT initiative to develop a stronger physics curriculum in high schools, after the Soviet Union launched Sputnik and fears spread that the United States was falling behind.

“Fortunately the physics teacher at the high school decided that the high school would be one of the pioneers, one of the guinea pigs,” Moniz said. “That’s when I got hooked on physics.”

He went to Boston College on a scholarship from his father’s labor union and became editor of Cosmos, the school’s science journal. After getting his doctorate in theoretical physics at Stanford, he joined the MIT faculty in 1973. He was the founding director of the MIT Energy Initiative and the MIT Laboratory for Energy and the Environment.

“He has this marvelous sense of humor,” said Susan Hockfield, the former MIT president. “You don’t feel as though you’re getting browbeaten by him. You feel like he’s teaching you. And he’s a master teacher.”

He served as a science adviser and as the undersecretary at the Department of Energy in the Clinton administration. Some say he is more politically savvy than his predecessor, Steven Chu, a Nobel-winning physicist from California who at times frustrated the White House by going off script.

“He’s the best-prepared secretary of energy — ever,” T.J. Glauthier, a former top-ranking energy department official who now advises energy companies, said of Moniz.

As he was preparing to take the job, Moniz consulted with George Shultz, who held four Cabinet positions under Presidents Nixon and Reagan and who worked with Moniz on the MIT Energy Initiative.

“I told him, ‘Stay close to members of Congress. In the end, they own the money,’ ” Shultz said in an interview. “You go and talk to them, just informing and whatnot — not just when you’ve got a crisis.”

Moniz said he has taken that advice. Several Republicans have praised his approach, and he recently had dinner with Representative Mike Simpson, an influential Republican on energy issues from Idaho.

But some environmentalists accuse Moniz of being too close with the oil and gas industry, citing ties established at the MIT Energy Initiative, which was funded primarily by those industries.

“So far he’s known for his deep love of fracked natural gas,” said Bill McKibben, a prominent environmental activist.

Moniz said damage to the environment should be mitigated, but his primary goal is lowering carbon levels in the atmosphere — even if that means promoting nuclear power or natural gas exploration through fracking, a controversial technique that uses pressurized water to fracture underground rock and release trapped gas.

“I frankly don’t care what the mix of technology is, as long as it gets us to low carbon,” he said. “And I think we need every arrow in the quiver.”

He bristles at criticism that the administration isn’t doing enough.

“Here we have the president who has done the most to commit to climate — I have been out there as a climate warrior,” he said. “But it’s not good enough because we refuse to exclude part of the portfolio.’’

Moniz strongly defends the use of government loans and grants for clean-energy companies, saying it is a vital way to develop technologies. While high-profile failures have caused Republicans to contend the government should not be investing in startups, Moniz said some risk is inevitable when you “push the envelope.’’

“We are not defensive about it,” he said, citing a remaining $50 billion in lending authority. “Quite the contrary. We have a lot more authority left. We’re going to use it.”

In the interview, Moniz would not discuss in any detail one of the more controversial proposals he must decide: whether to expand US exports of natural gas. He also would not weigh in on the Keystone Pipeline, which would carry oil from tar-sands fields in Canada to US refineries and ports. The highly controversial project is being reviewed by Secretary of State John Kerry, but the Department of Energy has an advisory role. Obama has said he will not approve the project if it would “significantly exacerbate” greenhouse gas emissions.

When asked if he believes it would increase carbon emissions, Moniz said, “I’m not commenting on Keystone.” He also declined to say if he has discussed the project with Kerry.

Moniz lives with his wife in Brookline, but his schedule keeps him away from home for weeks at a time. He often travels overseas to meet with foreign leaders about climate issues (although his home is about a mile and a half from Fenway Park, he watched Game Six of the World Series from the US Embassy in Japan).

The travel has kept him away from most games in the “Over-the-Hill Soccer League,” which he has played in for about 25 years (when he shows up, he is the only one who now has a security detail).

He also recently had a sobering responsibility, acting as the potential last line of defense in the event of a catastrophe. He was the “designated successor,” sitting out the State of the Union in case the president and other top officials died at once in the House chamber.

He was placed in an undisclosed location, with ample security and communications capability. The accommodations were not exactly meager.

“We had a steak dinner,” he said.

Matt Viser can be reached at matt.viser@globe.com.