The US Air Force is experimenting with a synthetic fuel that could become a cheaper fuel-alternative for the entire US military and even commercial aviation, officials say.

As the cost of a barrel of oil approaches $100 and US reliance on foreign oil sources grows, the Air Force, the single biggest user of energy in the US government, wants to find a cheaper alternative. Air Force officials think they may have found it in a fuel that blends the normal JP-8 fuel, currently used for the military's jet engines, with a synthetic fuel made from natural gas and liquid coal.

The 50-50 blend is less expensive – between $40 to $75 per barrel – and it burns cleaner than normal fuel. The synthetic fuel is purchased from US-based suppliers and then blended with the military's JP-8 fuel.

"We're making sure the Air Force is ahead of the curve so we can utilize this domestic resource instead of having to be both dependent on foreign sources and send dollars offshore instead of spending the dollars here in the US," says Kevin Billings, a deputy assistant secretary of the Air Force helping to oversee the initiative.

Last week, on the 104th anniversary of the Wright Brothers' first flight, the Air Force flew a C-17 Globemaster III from Washington state to New Jersey, the first transcontinental flight using the synthetic fuel. The flight was an attempt to demonstrate that pilots could fly the plane, considered a "workhorse" of the Air Force fleet, using "syn-fuel" without degrading the performance of the plane's engine.

The flight went well, officials say.

"It was completely unremarkable, which is exactly what we wanted to have happen," says Mr. Billings.

The flight followed a similar demonstration with a B-52 Stratofortress bomber last year. The fuel was then certified for use in the B-52 this summer. The service hopes to have all its planes certified to run on the fuel within the next five years. And by 2016, the Air Force hopes to meet half their US demand for fuel using the synthetic blend, first used in the 1920s, but further developed during World War II.

The Air Force would like to increase the amount of synthetic fuel it uses by that time, but recognizes that the private sector's push to get there will largely determine how fast the Air Force can move towards its goal or accelerate beyond it.

"[T]he market isn't moving fast enough yet for us to move any quicker," says William Anderson, assistant secretary of the Air Force for installations, environment and logistics.

The Air Force hopes to stimulate the private sector to embrace the move toward synthetic fuels, which will help private firms as much as it does the Air Force, says Mr. Anderson.

"We believe that we need domestic sources of aviation fuel to assure the American taxpayer long term that we can fight tonight and fight tomorrow," said Anderson during a recent roundtable for defense reporters. "And that requires that a domestic synthetic or alternative aviation fuel market grow in this country."

The reality that the US government, the largest net importer of foreign oil in 2006, can no longer rely so heavily on foreign oil has emerged as the price of oil climbs and instability in many countries increases.

At the same time, more demand for oil in places like China and India, has forced the US to look for other ways to fuel its own demand. Currently, about 58 percent of the nation's petroleum comes from foreign sources, and that is expected to jump to 68 percent by 2030, Air Force officials say.

In addition to being cheaper and ultimately more plentiful, synthetic fuel can also be greener, Air Force officials say. The fuel itself burns cleaner than regular JP-8 fuel, but the current process used to make the fuel produces nearly twice the amount of carbon.

The Air Force is requiring the plants that are being built to make the fuel to capture more of the carbon produced and reuse it, thus making the fuel ultimately greener, officials say.

The Air Force is taking "a leadership role" in the endeavor and working to ensure that the fuel can be used by Army, Navy, and Marine aircraft as well, according to Air Force officials.

Although the Air Force is the biggest user of energy in the US government, it only accounts for about 10 percent of the country's total demand for aviation fuel, a fact not lost on scientists working to develop the synthetic fuel for commercial aviation use. The Air Force is working with Boeing and Pratt & Whitney on the project. The C-17 was chosen for the transcontinental flight because its engines are similar to a Boeing 757 plane, commonly used by commercial airlines.

At least one member of Congress is on board.

"The Air Force alternative fuel program is as important to the nation as it is to the Air Force because it keeps focus on alternative fuels by the largest user of the fuel in the US government," said Rep. Jim Saxton (R) of New Jersey, who attended the event celebrating the landing of the C-17 in his state last week.

"We must continue to support the research ... to find cleaner, more environmentally friendly fuels that include both renewable and unconventional fuel," he added.