Geothermal energy and solar power project begins operation

The integration of a 26-megawatt solar power plant with a 23-megawatt geothermal energy plant — something never done before — was a multi-cultural affair that brought experts from four continents to work on the project near Fallon, says Francesco Venturini, president and chief executive officer of Enel Green Power of North America.

Enel last week commissioned the new solar energy facility at its flagship Stillwater geothermal energy plant in Churchill County.

Though much of the construction work was completed in the fourth quarter of 2011, the Enel engineering team had many lengthy meetings during Christmas as it figured out how to bring the solar plant online and integrate it with the existing geothermal energy plant.

Representatives from foreign countries that worked with Enel’s Reno-based team included:

• A contingent from Siemens Germany, which provided the crucial inverters that convert direct current to alternating current

• Executives from the Chinese company that supplied the solar panels

• Electrical engineers from Italy and Brazil.

“It was definitely a multi-cultural collaboration,” Venturini says. Enel soon may repeat the process, Venturini adds.

The company headquartered in Rome plans to enter the third phase of its development plans at Stillwater: integrating a concentrated-solar power facility with the existing geothermal operations.

Concentrated solar power differs from standard solar facilities in that it uses mirrors or lenses to concentrate sunlight onto a smaller area. The concentrated light is then converted into heat.

Reno quickly is turning into Enel’s North American research and development headquarters, Venturini says.

“We really are trying to make our Reno office and Nevada our center of R&D within the U.S.,” he says. “We are going to invest more money in that plant and add a pilot project that integrates two different technologies, CSP and geothermal. We are really betting on Nevada becoming a center of excellent for R&D and integration development.

“Enel has pipeline of projects in state, and when the opportunity arises and they become financially viable we will explore them,” Venturini adds. “For us Nevada is important — it is a small state, but it is in a very strategic place.”

Keeping the Stillwater geothermal plant in operation and honoring its power purchase agreement with NV Energy while bringing the solar facility online was one of the biggest challenges engineers had to overcome, Venturini says.

Enel Green Power North America began working on the idea of adding solar to the Stillwater plant in 2010, Venturini says, and it broke ground on the project at the beginning of August of 2011. More than 350 workers helped install the 120-acre solar facility in just a few short months. Bombard Renewable Energy of Las Vegas was general contractor on the project, which cost upwards of $70 million.

Approximately 81,000 solar panels were used in construction of the facility.

“It is a huge plant,” Venturini says. “We needed to integrate without losing production on the geothermal side. We are under contract with NV Energy, so we can’t stop production. Probably the biggest problem was reducing to a minimum time putting together the two plants.”

Enel was helped by the fact that its parent company, Enel Green Power, had engineers who were just finishing construction of a pilot project in Italy that integrated a solar thermal system to boost efficiency of a natural gas power plant, says Kossara Marchinkova, director of external relations and communications for Enel Green Power North America.

Enel brought the Stillwater and neighboring Salt Wells geothermal plants online in early 2009. The company acquired geothermal assets in Nevada, California and Utah from AMP Capital Partners in spring of 2007.