Enel Green Power has started construction of a 2 MW concentrating solar power (CSP) plant to operate alongside the existing 33 MW Stillwater geothermal power station in Nevada. The facility is already co-located with a 26 MW photovoltaic plant.
The Stillwater geothermal plant, consisting of two binary-cycle units, will be integrated with the parabolic trough CSP system so that they contribute to the same turbines. The hybrid plant will thus combine the continuous generating capacity of binary-cycle, medium-enthalpy geothermal power with daytime peak generation from the solar thermal component.
Enel says the CSP project is aimed at testing a new technology and determining how best to integrate it with a geothermal binary plant. The CSP system heats tubes of pressurized water. The integration work will enable the CSP component to raise the temperature of the geothermal fluid extracted from the wells to improve the cycle's yield and increase its electricity output.
The $15 million CSP plant is expected to start commercial operation by the end of the year. It will be capable of adding approximately 3 million kWh of electricity per year to the output of the existing hybrid plant. Combining three generation technologies is expected to produce approximately 200 million kWh of electricity per year. The energy produced is being sold to NV Energy through an existing 20-year power purchase agreement.