U.S. Government Accountability Office. Web posted March 12, 2012.

Governmentwide, 23 agencies and their 130 subagencies GAO reviewed implemented nearly 700 renewable energy initiatives in fiscal year 2010. The Departments of Defense (DOD), Agriculture (USDA), Energy (DOE), and the Interior were collectively responsible for almost 60 percent of all initiatives. The initiatives supported a range of renewable energy sources, and the most commonly supported sources were bioenergy, solar, and wind.

http://gao.gov/assets/590/588876.pdf [PDF format, 172 pages].