Assistant Secretary of Defense for operational energy plans and programs Sharon Burke said July 11 that the agency actively is pursuing alternative fuels because it has no other choice. Military operations consists of 79 percent of the department’s overall energy use, and as the petroleum supply could be limited in the future due to international conflict, climate change, or another reason, the government must be focused on making alternative fuels available for when that does happen. The Pentagon will continue using its current fleet for decades, so fuels need to be able to drop in to that equipment; the agency is working on certifying fuels for its equipment and will purchase them on a larger scale when they are cost-competitive.