Facing a steady stream of attacks over high gasoline prices, the Department of Energy has dusted off a new defense: a brand-new research fund that aims to make it cheaper for drivers to fuel their cars with natural gas.

President Obama personally unveiled the $30 million program last month during a speech at the University of Miami, and yesterday, the head of the Advanced Research Projects Agency-Energy (ARPA-E) returned to it time and time again as Republicans on the House Appropriations Committee asked him what the administration is doing to lower gasoline prices.

Experts agree that the Obama administration has little control over gasoline prices in the short term. Many of the president's preferred ways to save drivers money -- stricter fuel economy standards for cars, funding to hasten electric vehicles to the marketplace -- would only work in the long term and are not widely popular with Republicans. Natural gas, on the other hand, has no shortage of support on both sides of the aisle.

With some technical innovations, the fuel holds promise now that domestic drilling has made it as cheap as it has been in decades, ARPA-E Director Arun Majumdar told the Energy and Water Subcommittee.

"It is obvious that we have a lot of natural gas and it is inexpensive," he said. "It's just that it's not cost-effective to use that in light-duty vehicles."

Gasoline has the benefit of its existing network of pumping stations across the country; it would cost $100 billion to $200 billion to imitate that for natural gas, Majumdar said.

That is where natural gas will face the highest hurdles, even as large, centrally fueled fleets start to adopt natural gas as a cheaper alternative to gasoline.

But natural gas is already delivered to many homes as a heating and cooking fuel. If natural gas tanks and compressors were less expensive, people could fuel cars at home, Majumdar said. He pointed to research aiming to make the tanks from stronger, lighter carbon fiber, as well as new nanomaterials that absorb natural gas and could boost the capacity of a new breed of fuel tanks.

The ideas earned him praise from some Republicans on the subcommittee, including Vice Chairman Steve Womack, an Arkansas Republican. His state is home to the top-producing U.S. shale gas reservoir in 2011, known as the Haynesville Shale.

Womack said he is glad to see ARPA-E getting involved, especially with gasoline prices so high.

"People are looking for alternatives, and some of these alternatives are not ready for market," he said.

Also in that camp are electric cars, which are on the market but make up less than 1 percent of new cars sold. That is the solution preferred by environmentalists, who worry about shifting from gasoline to another fossil fuel with carbon emissions of its own.

Since its creation in 2009, ARPA-E has also put tens of millions of dollars toward research on electric car batteries -- an area that elicited a skeptical response from subcommittee Chairman Rodney Frelinghuysen as he pressed Majumdar for answers on gasoline.

"My constituents can't afford a Tesla," the Republican from northern New Jersey said, referring to the electric car manufacturer that released a $109,000 sports car as its first offering.

The company claims that the electricity to fuel the car costs about 2.6 cents per mile, meaning it could drive 150 miles for $3.91, the average price of a gallon of gasoline nationwide today.