Thermoeconomic optimizarion of OC-OTEC electricity and water production plants. Final report

Abstract

The objectives of this yearlong project were to: (1) assess the economic and technical viability of open-cycle ocean thermal energy conversion of (OC-OTEC) for the production of electricity and/or fresh water based on the current state of the art; (2) develop conceptual designs of optimized OC-OTEC plants that produce electricity and/or fresh water for plant sizes that are economically attractive; and (3) identify the research issues that must be resolved before a commercial plant can be built. Oceanographic data for six potential sites were evaluated and generic site characteristics were developed. The generic site has a 20/sup 0/C temperature differential between the ocean surface and a depth of 1000 m. This temperature differential occurs at a distance of 5 km from shore. Current and projected prices and requirements for electricity and water at potential sites were obtained. The state of the art of components comprising the OC-OTEC plant was reviewed. Design options for each component were identified. The highest performing, least costly, and least technically uncertain design for each component was selected. Component cost and performance models were then developed and integrated into thermoeconomic system models for single- and double-stage OC-OTEC plants that produced electricity and/or fresh water. A computerizedmore » optimization procedure was developed to obtain optimal (minimum cost) plant configurations for the production of electricity and/or fresh water. All plant types - floating, moored, shelf-mounted, shallow-water and land-based plants - were evaluated. Based on the state-of-the-art and typical characteristics of potential sites, the primary thrust of the program was directed towards shallow-water and land-based plants. The shallow-water/land-based plant configurations selected had a 5-km long cold-water supply pipe and a 1-km long discharge pipe for the evaporator and condenser.« less