HARTFORD, Conn. (AP) — As natural gas competes with increasingly costly oil as a heating fuel, researchers are now looking at it to run the family car.

United Technologies Corp. is among 13 recipients of federal Energy Department funding to come up with a natural gas tank for cars.

"We have a reasonable abundance of natural gas," said Craig Walker, director of the energy systems program at United Technologies Research Center in East Hartford. "How do we knock down the technical barriers?"

Natural gas is now used for commercial buses and trucks with larger tanks, and researchers want to apply the technology to cars.

The Energy Department says natural gas vehicle technologies require tanks that can withstand high pressure, are often cumbersome and are too large or too costly for smaller passenger vehicles.

The department awarded United Technologies and two partners a $4.4 million grant. Though it's a small portion of the $2 billion the conglomerate spent on research and development last year, Walker called the funding "reasonably good-sized." Following the three-year research program, United Technologies will develop a prototype tank for passenger cars.

Because natural gas is not typically sold at gas stations, researchers also are looking how to promote home fueling stations.

United Technologies also will be able to adapt the technology to the production of aircraft. Airplane engines, electrical components and other aerospace parts are a prime business of the conglomerate.

The research project is part of a $30 million initiative by the Department of Energy for 13 projects researching ways to use natural gas as a fuel for cars and trucks.

Other recipients include REL Inc. in Calumet, Mich., which will receive $3 million to develop high-storage capacity for tanks, and the Center for Electromechanics at the University of Texas at Austin, which will receive $4 million to develop an at-home natural gas refueling system that compresses gas.

Sen. Richard Blumenthal, D-Conn., said the Energy Department grants cannot be compared to Obama administration funding of Solyndra, a solar energy company that received a federal loan but went bankrupt, laying off its 1,100 workers and leaving taxpayers on the hook for more than $500 million.

"There are obviously criticisms of grants and programs at the Department of Energy," he said. "These are competitive grants. They're targeted. They're not promoting the success or failure of a company."