U.S. Deputy Defense Secretary William J. Lynn said energy is a critical element of military superiority for U.S. forces.
"Addressing energy needs must be a fundamental part of our military planning," he said in a speech in Washington.
Lynn said most of the energy consumed by the U.S. Defense Department supports military operations. More than 70 percent of the convoys in Afghanistan transfer fuel or water and some soldiers carry as much as 18 pounds of batteries.
He said that with a shift in military engagements from short, high-intensity fights to sustained operations, fuel management becomes a key consideration for war planners.
Lynn said the U.S. Navy was leading the way in alternative energy through its use of biofuel mixes in jet fighters while some U.S. Marine patrols use only solar power in operations in Afghanistan.
He said the military needed to find new ways of thinking about energy as military personnel armed with new technology are deployed.
"Any step we take to lower our energy use will allow us to spend resources on other warfighting priorities," he said.