OTEC Closed-Cycle Engineering Status

Abstract

Engineering analyses and component design studies during the period 1974–977 indicated the feasibility of constructing and operating floating OTEC plants and plantships in a variety of configurations ranging in power from 40 to 500 MWe. In August 1979, an at-sea test of a complete OTEC power system (Mini-OTEC) demonstrated performance in good accord with engineering predictions and established a firm basis for scale-up to larger sizes (Owens and Trimble, 1980). Heat exchanger operation at a level equivalent to 1-MWe power generation was demonstrated 1 year later in the OTEC-1 program. In 1981, a complete land-based OTEC power plant was constructed and operated under Japanese direction at the island of Nauru on the equator in the mid-Pacific ocean. During the period 1977-1980, a U.S. plan was developed, supported by public laws PL 96-310 and PL 96-320, to demonstrate OTEC feasibility at a 100-MWe level by 1985 and 500 MWe by 1990. Testing was to start with a pilot demonstration at 40 MWe (net). Preliminary design of baseline demonstration plants at this power level for moored operation off Punta Tuna, Puerto Rico, and for grazing operation west of equatorial Brazil with on-board ammonia production was completed in 1980 (George and Richards, 1980). Conceptual designs of larger plants and power systems for demonstration at the baseline level were also completed. In accord with the requirements of the Congressional actions, a Program Opportunity Notice (PON) was issued in September 1980 by DOE that offered cost-sharing support for innovative OTEC systems designs that contractors believed would be commercially viable if government cost sharing were made available during development of demonstration vessels. The PON asked for proposals for a development program to design, construct, and test a 40-MWe (net) closed-cycle OTEC system, which would be conducted in six phases beginning with conceptual design and continuing to preliminary design, engineering design, construction, deployment and operation, and, finally, transfer of ownership and contractor operation. The schedule was set to be consistent with the goal established by PL- 96-310 of demonstration of 100-MW OTEC operation by 1985. DOE stated its intent to fund five to eight awards for the first phase, with DOE providing $900,000 as its share of each contract awarded (Dugger et al., 1983).