The Department of Defense (DOD) is a major consumer of petroleum, with expenditures reaching approximately $17 billion in FY2011. Despite its significant fuel costs, DOD’s energy consumption represents a small fraction of the total U.S. energy use. The department faces substantial challenges related to fuel dependency, including financial risks from volatile prices, operational inefficiencies, and strategic vulnerabilities. In response, DOD is pursuing a range of energy initiatives aimed at reducing fuel needs and integrating alternative energy sources. For FY2013, DOD requested over $1.4 billion for operational energy initiatives. Congress has historically been involved in energy policy, focusing on energy reduction targets for DOD installations but not for operational energy. Key oversight issues for Congress include the coordination of energy initiatives, the development of reliable data and metrics, and projections of future fuel costs.