Wave, Tidal & Ocean Thermal Energy
For information on ocean energy in local environments, visit the Cape & Islands Energy Information Clearinghouse.

Power from the ocean can be obtained from two different sources of energy: kinetic energy from tides, waves, and ocean currents and thermal energy from solar heating of surface waters.

Tidal and wave energy technologies either use the energy of water in motion to directly to spin a turbine and drive a generator, or they transfer the energy to a working fluid that runs a turbine/generator. Tidal barrages operate like hydro dams in estuarine environments, restricting tidal flows. In-stream tidal energy and ocean current systems capture the energy from ebb and flood flows or circulations such as the Gulf Stream without altering the moving water. Wave generators rely on buoys, overtopping devices, tapered channels, and oscillating water columns to harness the up and down motion of waves.

Systems that create electricity from the thermal energy of the ocean take advantage of the temperature differences between warm surface waters and cold deep waters to bring seawater or a working fluid to a boil. In each of these systems the vaporized liquids are used to spin a turbine that activates a generator to produce electricity.

The ocean can provide power to make electricity from tides, waves, and heat.

(Photo courtesy of the National Renewable Energy Lab)