OTEC converts the solar energy, collected and stored in tropical waters, into electricity. The electricity may be either cabled to shore or used in situ for the manufacture of energyintensive products. Two countries, U.S.A. and Japan, are seriously pursuing OTEC. The development programs in both countries are similar. Presently, the emphasis is on the closed Rankine cycle with ammonia as the working fluid. The power plants are to be housed on floating platforms. If the electricity is to be cabled to shore, the platforms will be moored to the ocean floor. If the plants are to produce chemical products, they will graze from one location to another on the open sea to capture the largest available thermal resource.
Technical feasibility of OTEC appears certain. In the near term, OTEC can be economical for U.S. islands, which depend on imported oil for power generation. OTEC can enter the U.S. mainland market in the Southeast if projected capital cost for large plants is realized and high voltage, underwater d.c. transmission is developed beyond current state of the art. The islands market amounts to 8 GW and the U.S. market is estimated to be much larger. Penetration of the island market can begin in the early 1990s and of the mainland market after the year 2000.
A potential impediment to OTEC's accelerated deployment is capital. Although there are numerous important environmental and institutional questions, they are secondary to the economic and cost issues.
This paper addresses the economic, social and environmental issues pertinent to the commercialization of OTEC. The a priori assumptions are that technical problems can be solved and that in certain locations. OTEC can be competitive with conventional base-load power systems.