With the need for new, clean energy sources increasingly urgent, a growing sector of researchers and investors are looking to derive oils from algae to power vehicles. Perhaps surprisingly, though, it’s not a new idea.

In an in interview with AAAS, bioenergy expert Al Darzins said that the U.S. Department of Energy had explored the concept in its Aquatic Species Program from 1978 to 1996. But the current energy market, combined with concerns about climate change, have brought the idea roaring back—at the DoE and in the private sector.

Here’s the basic idea: When stressed, micro-algae produce oils, or lipids. But significant hurdles remaining growing the algae on a mass scale and harvesting and processing the oils.

“Right now our best estimation is that in order to produce a gallon of algae oil, it would be anywhere from $10 to $40 a gallon,” Darzins said. “We need to bring that down to a dollar or two.”

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