The energy from waves, tides, ocean currents, the natural flow of water in rivers, and marine thermal gradients can be captured to generate new sources of clean and renewable electricity. Although the marine and hydrokinetic (MHK) industry is at a relatively early stage of development compared to other renewable energy technologies (such as wind and solar power), the rivers, coasts, and oceans of the United States represent significant potential as a renewable energy resource. The United States uses about 4,000 terawatt hours of electricity per year. DOE estimates that the maximum theoretical electric generation that could be produced from waves, tidal and riverine currents, and ocean thermal energy gradients in U.S. waters is approximately 2,116 terawatt hours per year, more than half of the nation’s total annual electricity usage.