According to a story on DefenseTech, U.S. Navy researchers say they are close to a breakthrough toward turning seawater into jet fuel. The U.S. Naval Research Laboratory is working to extract the carbon dioxide and produce hydrogen gas from seawater, then converting carbon dioxide and hydrogen into hydrocarbons that can then be for JP-5 fuel.
Navy officials estimate the process used to convert the seawater to fuel would cost the Navy between $3 and $6 per gallon.
Source: Mike Hoffman, DefenseTech, October 2, 2012.