The following letter is to the Energy and Water Development Appropriations Subcommittee urging support of several programs vital to advancing U.S. leadership in clean energy. Specifically, the letter urges support of four complementary approaches to tackling the critical energy innovation challenges before us: Advanced Research Projects Agency-Energy (ARPA-E); Energy Innovation Hubs; Energy Frontier Research Centers (EFRCs); and the Regional Clean Energy Innovation Partnerships.