U.S. Department of Energy - Energy Efficiency and Renewable Energy

Geothermal Technologies Office

Geothermal Scores Well

April 12, 2006

The Renewables Portfolio Standard in the state requires a "least-cost best-fit" strategy for selecting new generation projects to fulfill its supply goals from renewables, explains a report prepared for the California Energy Commission by the California Wind Energy Collaborative. That strategy explicitly includes indirect integration costs in the bid evaluation process, and the report documents a multi-year analysis of integration costs for the period from 2002 to 2004.

The capacity credit analysis uses a conventional gas unit as benchmark, and shows that biomass has outage rates comparable to the gas benchmark unit, with a resulting capacity credit of 98%. With lower outage rates, geothermal facilities in both the north and the south of the state were assigned a rating of 109%.  

An analysis of regulation indicates that total system costs were $0.39 per MWh in 2004, with total load costs at $0.36. Geothermal was $0.02, biomass was $0.12, solar was $0.37 and wind ranged from $0.33 in the north to $0.58 at San Gorgonio, with an average for wind of $0.47/MWh.  

Report title: California Renewables Portfolio Standard: Renewable Generation Integration Cost Analysis

Also see: http://www.sparksdata.co.uk/refocus/redesign/showdoc.asp?docid=42756289&accnum=1