The Water Power Program's hydropower research and development (R&D) efforts focus on advancing technologies that produce electricity from elevation differences in falling or flowing water. For more than 100 years, hydropower has been an important source of flexible, low-cost, and emissions-friendly renewable energy. The program is currently leading efforts to increase the generating capacity and efficiency at existing hydropower facilities, add hydroelectric generating capacity to non-powered dams, and improve the environmental compatibility of hydropower. One such notable effort has been the interagency Federal Memorandum of Understanding for Hydropower through which the Department of Energy (DOE), the U.S. Army Corps of Engineers, and the Department of the Interior are continuing to advance their mutual goals for the development of clean, reliable, cost-effective, and sustainable hydropower generation in the United States.