Seawater may be a possible alternative to petroleum when fueling battleships

The world’s supply of petroleum is finite. The U.S. Navy, which runs on it, is not. Eventually, keeping its fleet afloat for generations to come may depend on another fuel—the kind that doesn’t dry up. Last month, a national-security commission advised Congress to fund shipbuilding and increase the U.S. naval presence in the Asia-Pacific region in the next decade to compete with China’s growing fleet. But upping production of petroleum fuel to meet potential future demands is at odds with the Navy’s plans to reduce its dependence on the fossil fuel, the deadlines for which are fast approaching. The Department of the Navy has pledged to cut petroleum use in the service’s commercial fleet in half by 2015, and produce at least 50 percent of its jet fuel using alternative sources by 2020.