Heat rejection from geothermal power plants. Final report

Comprehensive computer programs are developed for purposes of determining cooling makeup water requirements and electricity production costs for evaporative (wet) and dry/wet-peaking cooling towers, which are the principal cooling technologies for rejecting the heat from hydrothermal power plants. Parametric economic analyses were performed for both flash steam and binary conversion processes for various combinations of resource temperatures, climatological types, hydrothermal fuel costs, and cooling system makeup water costs. Results of these analyses are presented in a number of curves showing relative busbar cost of electricity as a function of relative amount of cooling makeup water required. These curves show that use of wet/dry cooling systems can cut makeup water requirements by factors of about 2 to 4 at the cost of an additional 10% to 25% in the busbar price of electricity. Turbine-generator performance curves are constructed for a range of condensing conditions for both the flash steam and hydrocarbon binary-cycle turbines. Estimates of hydrothermal resources in the western United States are also given.