One by one, Col. Jack Kelley set up the hurdles.

For the Air Force to ease away from its 700 million-gallon-a-year reliance on foreign oil, it needs a substitute that performs as well as kerosene-based jet fuel, known as JP-8. The new fuel would have to withstand extreme weather conditions, be usable without major modifications to jets and under a new federal law, emit less carbon dioxide.

And the way Kelley sees it, there's only one synthetic fuel in development that promises to meet all of those conditions: an algae-based compound being studied by Utah State University's Energy Laboratory's Center for Biofuels.

It "has characteristics that are almost exactly like JP-8," the Air Force engineer and former fighter pilot said in a talk at the Salt Lake City Library coinciding with Air Force Week. "And it's actually much cleaner burning, so it's a better fuel for us."

The military's Defense Advanced Research Projects Agency is sinking tens of millions into programs to develop a commercially viable algae fuel, including a $4.5 million investment into Utah State's efforts. Part of a team led by California defense contractor General Atomics Corp., USU's energy lab is helping build an algae-biofuel facility capable of producing 50 million gallons of fuel a year.

If successful, it would be a significant step toward the military's goal of having about a quarter of its fuel synthesized from domestic sources by 2016.

Algae also shows potential for addressing the nation's need for carbon-neutral liquid transportation fuels, said Jeff Muhs, the USU center's director. He testified on the subject last month before the Senate Appropriations Subcommittee on Energy and Water Development.

The simple, carbon-sucking plant -- which created much of the world's coal reserves, millions of years ago -- can grow rapidly, yielding vast lipid-rich plumes that can be harvested as an energy source.

Using algae for fuel would not encroach on the food supply, a drawback for options like corn -- a favorite source for another biofuel, ethanol. Nor would algae require the land, fresh water and fertilizer on near the scale as corn, Muhs said on Wednesday.

While an acre of traditional crops yields just a few hundred gallons of biofuel, an acre of algae, fed by brackish or saline water such as that found in the Great Salt Lake, could yield between 1,500 and 10,000 gallons, Muhs said.

Still, daunting technical hurdles to large-scale production remain, and researchers across the country are trying to tackle them. "Feedstock production is the biggest challenge," Muhs said. "As the algae grows thicker, it shades the algae below."

The Utah group is working to identify high-lipid algae strains from the Great Salt Lake and to maximize the amount of sunlight falling on cultivated algae.

While excited about algae fuel, Kelley said the military will be discerning. He noted that replacement fuels are being tested, engine by engine, on aircraft such as the B-52 Stratofortress, which has eight engines.

The F-16 fighter jets Kelley flew for the Air Force only have one engine.

"So by the time you put the fuel in that airplane," he said, "it's either going to work or it's not."

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