Researchers with the Pacific Northwest National Lab have discovered that algae could replace 17 percent of U.S. oil imports. Their study, published in the journal Water Resources Research, was the most detailed look so far at how much biofuel algae could make and how much land and water it would take to do it.
In 2009, the U.S. imported about half of its petroleum. Extracting and refining the oils produced by algae could be a viable home-grown substitute, researchers found, but it will require a lot of water (eek, 350 gallons per gallon of oil). To get the most bang for your water buck, they concluded, the algae should be grown in the sunniest and most humid regions of the U.S. – Gulf Coast, the Southeastern Seaboard and around the Great Lakes.
Among their findings:
- American-grown algae could produce 21 billion gallons of oil – 17 percent of the petroleum the U.S. imported in 2008 for transportation.
- The oil could be grown on land roughly the size of South Carolina
- It would require 350 gallons of water per gallon of oil, or a quarter of what the country currently uses for irrigated agriculture.
- Up to 48 percent of the current transportation oil imports could be replaced with algae, but growing it would require lots more water and land.
- Growing algae uses between 8.6 and 50.2 gallons of water per mile driven on algal biofuel.
- Corn ethanol ranges widely in its water requirements: Between .6 and 61.9 gallons of water per mile (depending in part on where it's grown)
- Petroleum uses between .09 and .3 gallons of water per mile
- Algae can produce more than 80 times more oil than corn per hectare per year
- Because algae consume carbon dioxide, they are considered a carbon neutral energy source
- Algae can feed off carbon emissions from power plants
- Algae digest nitrogen and phosphorous, common water pollutants, and can grow in – and clean – municipal waste water