Compound Hybrid Geothermal-Fossil Power Plants: Thermodynamic Analyses and Site-Specific Applications

摘要

The analysis of hybrid fossil-geothermal power plants is extended to compound hybrid systems which combine the features of previously analyzed systems: the geothermal-preheat and the fossil-superheat systems. Compound systems of the one- and two-stage type are considered. A compilation of working formulae from earlier studies is included for completeness. Results are given for parametric analyses of compound hybrid plants. System performance was determined for wellhead conditions of 150, 200, and 250 exp 0 C, and for steam fractions of 10, 20, 30, and 40%. For two-stage systems an additional cycle variable, the hot water flash fraction, was varied from 0 to 100% in increments of 25%. From the viewpoint of thermodynamics, compound hybrid plants are superior to individual all-geothermal and all-fossil plants, and are shown to have certain advantages over basic geothermal-preheat and fossil-superheat hybrid plants. The flexibility of compound hybrid systems is illustrated by showing how such plants might be used at six geothermal sites in the western United States. The question of the optimum match between the energy resources and the power plant is addressed, and an analysis given for a hypothetical geothermal resource. (ERA citation 05:018797)