Economic Research Service, U.S. Department of Agriculture. May 2013.

Rising energy prices and changing energy and environmental policies have transformed the relationship between the energy and agriculture sectors. Traditionally, the relationship has been one-way, with agriculture using energy products as an input in production; during the past decade, however, the energy sector’s use of agricultural products as renewable-fuel feedstocks has increased substantially. This report examines both sector and farm-level responses to changing market and policy drivers such as the increased production of biofuel crops and other sources of renewable energy, together with changes in production practices to economize on energy-based inputs like fertilizer. We provide insight into how farmers have adapted to the changes and update and provide new data on the evolving linkages between the energy and agricultural sectors. 

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].