"The U.S. military is by the far the largest user in the country, so we can create a market for it," Mabus said. The Navy is the "guaranteed customer" needed to get the industry "across the so-called valley of death from a good idea to commercial scale," he said.

The armed forces say they've been successful testing fuels produced from sources as diverse as animal fat, frying oils and camelina, an oil-bearing plant that's relatively drought- and freeze-resistant.

Major Aaron Jelinek, the lead solo pilot in the Air Force's Thunderbirds flight demonstration team, performed aerobatics including loops, rolls and formation flying at Andrews Air Force Base in Maryland on May 20-21. It was the F-16 fighter jet's first flight using a fuel made from the camelina plant.

"I could tell no difference between flying that day when I had biofuel in my tank versus flying the day before or the day after," Jelinek said in an interview. "It was a normal demonstration, one that we perform at 70 shows during the year and in many more practices than that, doing the exact same maneuvers and the exact same show sequence as any other day."

Green Hornet

The military wants its vehicles, except for the ships that are nuclear-powered, to be able to use new combustibles, cutting fossil fuel imports from politically unstable nations.

"We do buy a lot now from countries that we sure wouldn't let build our aircraft or ships, but we give them a say in whether they sail or fly because we buy our fuels from them," said Mabus.

The Navy has flown its Green Hornet fighter aircraft at 1.7 times the speed of sound using a biofuel blend and aims to have certified all of its aircraft for the fuels by year-end.

While the tests were done in the U.S., once certified, the forces will be able to operate aircraft on biofuels anywhere, including war zones such as Iraq, Afghanistan and Libya.

"If the fuel is available, whether it's in Afghanistan or it's in Kentucky, we want to be able to use it," said Geiss.

The Navy's fuel bill rose $1 billion this year because of the conflict that cut off Libyan output, said Mabus.