And the question is whether President Obama will seek out a scientist in the the mold of Mr. Chu or change course and look for someone with more political experience?
Some say he may get both with Ernest Moniz, a nuclear physicist at the Massachusetts Institute of Technology in Cambridge, Mass. Mr. Moniz, who also serves as the director of MIT's Energy Initiative, has emerged as a top candidate to replace Chu, as first reported by Reuters.
No stranger to Washington, Moniz served two years as the associate director for science in the Office of Science and Technology Policy in the Executive Office of the President, beginning in 1995. In 1997, he was appointed under secretary of the Department of Energy, a post he held until January 2001. He is currently a member of President Obama’s Council of Advisors on Science and Technology and of the Department of Energy's Blue Ribbon Commission on America’s Nuclear Future.
In 2011, Moniz testified before Congress on the role of natural gas in America's energy future. Calling it "one of the most cost-effective means by which to maintain energy supplies while reducing CO2 emissions," Moniz endorsed natural gas as a "bridge" fuel to a low-carbon future.
Those remarks unnerved environmentalists, who say that natural gas drilling techniques pose a serious threat to air and water resources. Some of them have gone public with their concerns about Moniz.
"If we pursue our fossil fuel addiction by expanding fracking, which Mr. Moniz will likely advocate, the oil and gas industry will thrive while true energy efficiency and renewable solutions languish," said Wenonah Hauter, executive director of Food & Water Watch, in a statement last week. "Our water, public health and climate would suffer."
Meanwhile, some fracking proponents are expressing a bit of relief at the prospect of an Energy Secretary Moniz.
"[A]t least it isn’t one of those fossil fuel-loathing, hardcore eco-zealots currently lobbying President Obama so hard against the practice of hydraulic fracturing altogether," reads a post on Hot Air, a conservative blog.
Moniz isn't the only name speculated to be on Obama's short list. A slew of former politicians, including former North Dakota Sen. Byron Dorgan, former Colorado Gov. Bill Ritter, former Washington Gov. Chris Gregoire, and former Michigan Gov. Jennifer Granholm, have also been named as potential candidates.
When asked about his prospects last November, Mr. Dorgan was elusive.
“Speculation is a big business in Washington, D.C. If we could find a way to price it, somebody would get rich,” Dorgan said in an interview with Platt's Energy Week TV. “I am very interested in energy issues, but I have served in public service for a long, long time.”
Mr. Ritter, who now serves as the director of the Center for the New Energy Economy at Colorado State University, said he was flattered to be considered for the position.
“As a nation, it’s a critical time to focus on energy policy," Ritter said in a statement last December. "Coloradans have done a remarkable job putting in place an effective energy agenda and this consideration is a reflection of the energy work we initiated while I was governor."
Chu, a Nobel physicist with limited experience in Washington, was a unique choice for the position, which has typically been held by politicians and industry leaders.
In his four years at the Department of Energy, Chu earned praise from the left for securing funding for renewables, including more than $90 billion in Recovery Act funding. That same funding, particularly the $34.5 billion in loan guarantees paid to private companies, drew ire from the right, especially after the failure of Solyndra and a few other companies that had received the guarantees.