Algae would produce considerably more transportation energy than canola and switch grass for every acre planted and can be grown on poor-quality marginal land that cannot be easily used to grow food crops such as corn, University of Virginia researchers said in a release Wednesday.
However, from an environmental impact standpoint, algae-based fuel has mixed performance compared with other biomass sources, engineering Professors Andres F. Clarens and Lisa M. Colosi said.
Algae-based biodiesel production uses more energy, in the form of petroleum-powered processes, than other biofuels and also requires substantial amounts of water and emits more greenhouse gases, they said.
"It comes down to value-driven questions," Colosi said. "Do we value driving long distances in SUVs that require a lot of fuel? If so, we need to look at algae so we can produce as much fuel as possible.
"If we are concerned about energy use, climate changes and water supply, then we need to think more strongly about how we can best use canola and switch grass," she said.
Environmental costs and benefits associated with production of the various bio-fuels needs to be considered, the researchers said.
"Ultimately there is no silver bullet for replacing petroleum as a transportation energy source," Clarens said. "We've seen that alternatives typically come with unforeseen burdens. We saw it with ethanol, and we're seeing it now with shale gas."