The Department of Defense (DOD) consumes about 60 percent of all energy used at federal government facilities. To encourage an increased use of energy from renewable sources, such as solar and wind power, (1) the Energy Policy Act of 2005 (the 2005 Act) directs DOD to consume at least 3 percent of its total electricity from renewable resources starting in fiscal year 2007; (2) Executive Order 13423 (the 2007 Executive Order) directs that an amount equal to half of the statutorily required renewable energy be generated by sources placed into service in 1999 or later; and (3) the 2007 Defense Authorization Act directed that at least 25 percent of electricity consumed by DOD come from renewable sources in fiscal year 2025. GAO was asked to examine (1) DOD's progress toward these three key goals for consuming renewable energy in fiscal years 2007 and 2008, (2) challenges to DOD meeting those goals, and (3) DOD's plans to meet the goals. GAO reviewed relevant laws and DOD and Department of Energy (DOE) policy, plans, and data; interviewed agency officials; and visited DOD facilities. GAO makes 5 recommendations to DOD, including that DOD accurately report progress toward the goals and develop a long-term, DOD-wide plan to address challenges and meet goals. DOD concurred with 4 recommendations and partially concurred with 1, agreeing with its intent but stating that it is a service responsibility.