Extracting energy from the oceans: a review

Renewable energy resources are expected to minimize environmental impact and present none of the security and waste disposal problems associated with nuclear power plants. Eight methods, and a number of variants, of obtaining energy from the oceans are presented: ocean thermal, kelp bioconversion, ocean waves, tides and tidal currents, ocean winds, ocean currents, salinity gradients, and ocean geothermal. Each method is discussed in terms of concepts, geographic areas applicable, and development schedule and costs insofar as information is available. None of these methods produces ''excess'' heat into the environment, as do fossil-fuel and nuclear-power generating plants. Most of the methods represent relatively new technologies.