Abstract
Ocean Thermal Energy Conversion (OTEC) uses the temperature differential between warm surface ocean water and deep cold ocean water to generate power through a heat exchanger process. Deep ocean water is generally between 2o and 4oC; the temperature differential of 20oC needed for OTEC is found only in tropical waters. In the United States, OTEC is feasible year round only in Hawaii and island territories in the Caribbean and the Pacific. In addition to power from OTEC, cold ocean water can be used in place of traditional air conditioning, through a process known as SWAC (seawater air conditioning) that runs cold water through buildings and exchanges the heat, much like a heat pump. The deep OTEC water pumped to the surface may also be advantageous for other uses such as aquaculture. There is no established method of determining potential environmental effects of OTEC and SWAC. In general, the greatest risk to the marine environment from OTEC will be the return of large volumes of deep ocean water to the surface of the ocean where the temperature shock may kill organisms and potentially affect the stability of the water column. The deep cold water can be defused at depth to prevent these effects. There is little information about potential concerns from local communities where OTEC might be developed. There is a need for a broad education and outreach program to ensure that communities and local officials are well informed of the benefits and risk of OTEC.
Four use cases for developing OTEC are outlined for U.S. waters in Hawaii, Puerto Rico, St. Croix, and Guam. A simple education and outreach program is also outlined.