The Mitt Romney concept of federal funding for clean energy is not dead.

The Advanced Research Projects Agency-Energy, or ARPA-E, modeled after the Pentagon's successful DARPA program, is wrapping up its fifth annual conference on Wednesday. It is possibly the only federal clean energy research program to win consistent support from Republicans -- even Romney gave it plaudits on the 2012 presidential campaign trail when Republicans were attacking Obama administration investments in failed clean-energy ventures like solar panel maker Solyndra.

There's a key difference between ARPA-E and the oft-criticized federal stimulus loan guarantees for green energy. The former is basic research, the latter applied. Conservatives are more supportive of research that aims to steer certain technologies toward commercialization than efforts that reward specific companies.

"There is no other program in the government that does what this program does in the way it does it," Sen. Lamar Alexander, R-Tenn., the top Republican on the Senate Appropriations Energy and Water Subcommittee, told the Washington Examiner.

House Republicans say last year's budget proposal that cut the program's spending by 81 percent was a one-time deal because of forced automatic spending cuts from sequestration. Clean-energy advocates and Democrats said the move showed Republicans were beholden to fossil fuels.

Rep. Mike Simpson, R-Idaho, chairman of the House Appropriations Energy and Water Subcommittee, said those who read tea leaves on ARPA-E's future are better served looking at the $280 million it received for fiscal 2014, $15.5 million above enacted fiscal 2013, in the spending deal struck last month.

"We were marking up bills to numbers that were unrealistic, and we knew that when we were marking them up," Simpson said of the initial House Republican request to gut ARPA-E. "When we got the final [budget] numbers, we were able to put the funding where it needed to go."

ARPA-E aims to get certain technologies to market that the private sector deems too risky to undertake. It rewards companies that reach a metric — say, halving the density of lithium-ion batteries for electric vehicles — but does not prescribe a method for arriving at that point.

"We're standing today on the shoulders of those who invested in research that came before us, and there are some things that are so risky that the private sector never will undertake. And I think that's where it's appropriate for government to be involved," Rep. Alan Nunnelee, R-Miss., a member of the House Appropriations Energy and Water Subcommittee who said he supports ARPA-E, told the Washington Examiner.

Added Alexander: "Once Republicans learn about this, they usually like it. ... They're off to a very good start."

ARPA-E was created under former President George W. Bush's administration, though it didn't get any funding until Obama's tenure began in 2009.

It has spent $900 million on 362 projects in its five years. Of those projects, 22 have attracted $625 million in private-sector investment following an initial $95 million from the federal government. Another 24 started their own companies, and 16 others partnered with government agencies for further development.

Still, some conservatives feel the program is unnecessary. They contend the National Science Foundation and Energy Department-run national laboratories could do the work just as well, and that eliminating ARPA-E would shed administrative costs.

That will be a constant threat, especially in an era of fiscal tightening, for the relatively young program, said Eli Lehrer, president of the conservative R Street Institute.

"Age certainly affects it, because when you've been around a while, you've built a constituency," Lehrer told the Washington Examiner. "So zero-funding [the National Science Foundation], the national labs or DARPA is unthinkable. But ARPA-E gets talked about all the time."

But because both Simpson and Alexander are supporters, the program has influential Republican backers. The pair comprise the top Republicans on the spending subcommittees that oversee ARPA-E.

"Once people study it, it's hard to be against the cousin of a small entity [DARPA] that created GPS and the Internet," Alexander said. "If ARPA-E does one-tenth what DARPA did, then it will be well worth the taxpayers' investment."