Military spending on clean energy increased from $400 million in 2006 to $1.2 billion in 2009, the report -- "From Barracks to the Battlefield: Clean Energy Innovation and America's Armed Forces" -- said. It was prepared by Pew Charitable Trusts.
"As one of the largest energy consumers in the world, the Department of Defense has the ability to help shape America's energy future," said Phyllis Cuttino, director of the Pew Clean Energy Program. "DoD's efforts to harness clean energy will save lives, save money and enhance the nation's energy and economic future. Their work is also helping to spur the growth of the clean energy economy."
The U.S. military's experience in Afghanistan and Iraq, where about 80 percent of all supply convoys carry fuel, has helped drive the push for efficiency and alternate fuel, the report said.
The Navy plans to test a hybrid electric drive system on the USS Truxtun, a guided-missile destroyer.
Notable deaths of 2014 [PHOTOS]