Officials Celebrate Hybrid Geothermal-Solar Power Plant


On Tuesday, Enel Green Power (EGP) and officials held a dedication ceremony at the company’s Stillwater renewable hybrid facility in Fallon, Nev. The company says Stillwater is the first power plant in the world to combine medium-enthalpy, binary-cycle geothermal, solar thermal and solar photovoltaic technologies at the same site.

The event marked the one-year anniversary of the completion of the site’s 2 MW concentrating solar power (CSP) project and the full integration of all three technologies. Stillwater began operation in 2009 with a 33.1 MW geothermal plant. In 2012, EGP added a 26.4 MW solar PV project, and the company finished the CSP project in 2015.


According to EGP, the CSP portion consists of 22 rows of parabolic-trough solar concentrating mirrors. Each row is 700 feet and each mirror is approximately 20 feet across, for a total of 2,772 mirror panels built on 21 acres. The company notes a study found that combining the solar thermal facility with the geothermal plant increased overall output at Stillwater by 3.6% compared with production from geothermal only.

EGP CEO Francesco Venturini was joined at the event by Nevada Gov. Brian Sandoval, Italian Prime Minister Matteo Renzi, Enel Group CEO Francesco Starace, National Renewable Energy Laboratory Director Dr. Martin Keller, and other state and local officials.

“The lessons we are learning at this advanced geothermal-solar facility will be key to the development of other hybrid plants throughout the world,” said Starace.
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According EGP, combining generation technologies of different profiles at one production site increases energy availability and reduces energy intermittency. Geothermal and solar (thermal and photovoltaic) are complementary, meaning that production from solar is higher during the sunniest and hottest days of the year, when the thermal efficiency of the geothermal plant is lower. The increased delivery of power during peak hours also enables a more load-following production profile. At the same time, EGP continues, sharing existing infrastructure enables costs savings and a reduction of the plant’s environmental impact per unit of energy produced and delivered.

Photos courtesy of EGP

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