By the time Congress mandated ethanol subsidies and usage in 2005, it was difficult to find anyone in the environmental community who thought it was a good idea - even Al Gore, who championed it for almost two decades, is against it now.

Worse, while in vogue it overshadowed something that was both more cost- and energy-effective; algae.

Microbiologists have always known that algae contains oil that can be turned into diesel fuel - and in better quantities than other alternatives. Soybeans produce about 50 gallons of oil per acre per year, and canola produces about 130. Algae, however, can produce about 4,000 gallons per acre a year. Algae requires only sunshine and non-drinkable water to grow.

Keith Cooksey is one of many U.S. scientists who studied the feasibility of turning algal oil into biodiesel in the 1980s. The U.S. Department of Energy, through its Aquatics Species program, funded their research. Cooksey's lab made a number of discoveries. Scientific journals published his findings.

Funding dried up, however, and the scientists went on to other things. Cooksey now directs the Department of Defense's EPSCoR program for Montana but a few months ago he started getting phone calls and e-mails from researchers and others who read about his algal work on the Internet or had seen it referenced in scientific journals.

Revived interest in microalgae stems from high oil prices and the renewed interest in alternative fuels.

"It's a very strange feeling," said Cooksey, now 72. "You don't usually have people bending your ear on what you did 20 years ago. Science doesn't work that way, but in this case, it did.

"Our lab was one of three or four in the world doing research that nobody was really interested in. Now, suddenly lots of people are interested in it."

One design that was tested in the 1980s is a shallow pond that looks like a raceway. Another is a system of deeper ponds. Algae can be grown especially well in desert states that have plenty of sunshine and access to water unusable for traditional agriculture or drinking. Because of its salt content, salt water is more economical than fresh water for growing algae, so southwestern states with saline aquifers might find it easy to grow them.

"In principle, lipids from microalgae are suitable for refining into conventional liquid fuels," said a 1983 annual report from the Solar Energy Research Institute that provided Cooksey's funding and some algal cultures. "Indeed, in the past, biological oils have been refined to fuels during shortages in petroleum supply."

David Tooke, director of operations at Sustainable Systems in Missoula, said, "With new interest in biofuels, it's another opportunity to supply those fuels. As far as surface area needed, it's more reasonable to assume we could attain those levels of production from algae versus agricultural crops."

Twenty years ago, algae looked promising but interest died down as oil prices dropped. Can algal biofuel make it this time around?