42 U.S.C. § 17211. Definition

For purposes of this part, the term “marine and hydrokinetic renewable energy” means electrical energy from—

1. (1)
   (1)waves, tides, and currents in oceans, estuaries, and tidal areas;
2. (2)
   (2)free flowing water in rivers, lakes, and streams;
3. (3)
   (3)free flowing water in man-made channels; and
4. (4)
   (4)differentials in ocean temperature (ocean thermal energy conversion).