Projected Engineering Cost Estimates for an Ocean Thermal Energy Conversion (OTEC) Central Station

This Note summarizes an investigation into the potential cost reductions that might be achieved if certain engineering, construction, and financial improvements were realized in the OTEC concept. Six options have been analyzed: water-side heat transfer enhancement (for tube-and-shell heat exchangers), plate-type heat exchangers, fiberglass-reinforced-plastic (FRP) cold-water pipes, elimination of the requirement that the transmission cable be buried at ocean depths of less than 300 feet, a shorter construction period, and a reduced fixed charge rate. It was found that the changes having the most effect on capital cost are the two heat exchanger options and the shorter construction period. However, to achieve major reductions in capital costs, on the order of 30 percent, a combination of one of the heat exchanger options in conjunction with the cold-water pipe, transmission cable, and construction period options will be required. Additionally, both offshore and onshore applications were considered for the islands of Puerto Rico and Hawaii. Finally, the projected engineering cost estimates were compared with the costs of coal-fired and nuclear plants.