Advances in Turbine and Direct Contact Condenser Configurations, and Balance of Plant Considerations
By: Matt Fishman, Josh Gunderson and William Harvey, POWER Engineers
The bottom exhaust steam turbine coupled with a spray type direct contact condenser has been a common geothermal plant configuration for large (50+ MW) units since the 1970s. In recent years, a wider variety of available turbine and condenser configurations has proliferated, including axial exhaust turbines exceeding 50 MW and direct contact condensers with structured packing. In this paper, we review key characteristics of the various equipment configurations, provide factors to consider in the evaluation of turbine and condenser offerings, and present a case study of several configurations for a reference plant to illustrate relative differences in plant performance and cost impacts. We conclude that recent technological advancements in axial exhaust turbines and direct contact condensers can result in improved project economics based on increased gross and net power output and cost reductions for the powerhouse, major equipment, civil works, and operations and maintenance.