Comunidad del pacífico en perspectiva - Volumen 2

OCEAN RESOURCES AND OCEAN TECHNOLOGIES IN TRE PACIFIC because of the prevalence of a maximum of thermal difference between surface and deeper water. But that temperature differential is low compared to other sources of motive power for the turbines such as steam and thus Carnot and practical efficiencies of OTEe plants are also low. Therefore, they are subject to economies of scale: input-output calculations considering presentIy possible techo nologies indicate that 500 megawatt OTEC plants are or can soon be competitive with coal - or oil-fired power plants in the same order of magnitude (Perry, 1977). Few Pacific islands presently have such power demands, but one can conceive of industries to be developed which will greatly increase island power needs (e. g., copper in Fiji). There are also possibilities oE joint uses of OTEC devices by several small nations. The present OTEC test installation at Keahole Point on the island of Hawaii has successfully produced 50 kwh of electricity. Experiments will be performed there with floating and land-sited OTEe pilot plants prominently including floating platform designs and materials testing for technical and economic advantages. lt is also intended to establish there, with more reliability than can now be adduced, what the possibilities of oTEc-associated aquaculture might be. The enriched nutrient con– tent of the deep water has interesting possibilities in this regard; for their realization, these would have to be combined with new inventions in aquacultural engineering. An important challenge for these will be to optimize growing temperatures, for growing things in the tropics, including the tropical ocean, has many advantages in terms of energy and energy productíon, many of which are not yet realized. The initia! advan– tage of the tropics was an extended growing season which permit– ted the development of such unique crops as sugar cane, pineapple, and bananas. lt is true that some of these advantages have been lost by the development of sugar beets and com and the expanding horticulture of competitive temperate zone fruits. As fertilizer can be made available through earlier mentioned natural gas and phosphate deposíts as well as from OTEe sources, apart from the smaller-scale recycling of organíc materials, the advantage may be regained by developing multiple cropping on the tropical lands, that is, by planting together and/or in proper succession combi- 141