Gephyrocapsa oceanica

Approximately 17 percent of oil imported into the U.S. to be burned in vehicles could be replaced by algal fuel by 2022, according to a study conducted by the Pacific Northwest National Laboratory (PNNL). That is, if the U.S. makes a commitment to reduce its dependency on foreign oil by focusing on production of algal fuels. Mark Wigmosta, lead author of the study and a PNNL hydrologist, said in a statement that:
Algae has been a hot topic of biofuel discussions recently, but until now no one has taken such a detailed look at how much America could make and how much water and land it would require. This research provides the groundwork and initial estimates needed to better inform renewable-energy decisions.
After analyzing 30 years of meteorological data, the PNNL research team concluded that 21 billion gallons of algal fuel could be produced by 2022 in the U.S. To achieve that amount of output, algae would have to be grown on land equal to the size of South Carolina. While that's a massive chunk of Earth, the U.S. does have loads of unused land.

[Source: Autopia, Domestic Fuel | Image: Wikimedia Commons – C.C. License 2.0]