Marine Energy Act This bill amends the Energy Independence and Security Act of 2007 to revise and reauthorize through FY2022 the program of research, development, demonstration, and commercial application to accelerate the introduction of marine and hydrokinetic renewable energy production. The program must give priority to fostering accelerated research, development, and commercialization of technology. The meaning of "marine and hydrokinetic renewable energy" is expanded to include all forms of energy, not just electricity, from: (1) waves, tides, and currents in oceans, estuaries, and tidal areas; (2) free flowing water in rivers, lakes, and streams; (3) free flowing water in man-made channels; and (4) differentials in ocean temperature (ocean thermal energy conversion). National Marine Renewable Energy Research, Development, and Demonstration Centers must support in-water testing and demonstration of marine and hydrokinetic renewable energy technologies, including facilities capable of testing: (1) marine and hydrokinetic renewable energy systems of various technology readiness levels and scales, (2) a variety of technologies in multiple test berths at a single location, and (3) arrays of technology devices.