“At noon on a typical workday, technicians in a two-story control room monitor a dozen screens showing the heat generated by each array of mirrors. As temperatures creep past 700 degrees, icons blink to red from green, indicating the center is ready to feed electricity to the California grid.”

The resulting steam turns turbines that generate electricity — enough to power 112,55 L.A.-area homes. Concentrated solar thermal’s potential has not escaped the attention of forward-thinking investors with big money:

“Chevron, Goldman Sachs, FPL, PG&E and other companies have filed more than 50 applications with the Bureau of Land Management to lease government-owned desert property for solar power systems. Google’s philantropic division put $10 million into eSolar, a start-up in Pasadena, California.” –Greg Chang, Bloomberg.com

Las Vegas, Nevada - The current period of sustained growth in the American Southwest is putting tremendous demands on important resources like water, wildlife habitat, and, with the light beaming from the top of Las Vegas’ Luxor Hotel as a reminder, electricity. Nevada currently gets about 90% of its electricity from fossil fuels, and the majority source fuel is natural gas. As natural gas prices are predicted to rise, a debate is stirring about whether the state needs to build new coal-fire power plants to meet current needs, or whether it should tap its renewable resource potential. For that reason, Acciona Energy could not have picked a better time than today to dedicate their new 64 MW concentrating solar power plant (CSP) in Boulder City, Nevada, less than thirty miles from the Las Vegas strip. And with a star-studded collection of speakers like Ed Begley Jr., NASA astronaut Dr. Sally Ride, and Apple co-founder and tech whiz Steve Wozniak, the Spanish-based Acciona dedicated the facility in true Las Vegas style.

The 300-acre site in Boulder City uses parabolic trough collectors to generate electricity. The 760 mirrored troughs track the movement of the sun’s path, and their 184,000 mirrors face the sky and concentrate the sunlight to a large metal and glass receiver in the middle of the trough that holds circulating oil. The oil travels to heat exchangers, which heat water and create steam that spins a turbine.

At 64 megawatts (MW) of generation capacity, Nevada Solar One is the largest CSP plant to be built in 16 years and it makes Nevada the largest per capita producer of solar power in the country. After roughly a decade of little growth for the industry, CSP is coming back strong, as is further evidenced by today’s announcement by Abengoa Solar that they will be building a 280 MW concentrating solar facility in Arizona.

The absence of any new CSP over the last 16 years leaves many people scratching their heads and asking themselves, why?

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Technology

The American Southwest would be the home of massive amounts of solar power needed for this clean energy conversion. Specifically, two types of solar power would be employed: Photovoltaic (PV) cells and concentrated solar power.

According to the solar grand plan, 30,000 square miles of PV cells would provide 3,000 gigawatts (GW) of energy. The “30,000 square miles” part made me flinch, but already existing solar installations indicate that the land needed for each gigawatt-hour of solar energy in the Southwest is less that the amount of land needed to run a coal plant and mine the fossil fuel for it.

Concentrated solar power would supply about one-fifth of the solar energy in the plan. Concentrated solar power uses long metallic mirrors that focus the sun’s rays onto a pipe filled with fluid. The fluid is heated and runs through a heat exchanger that produces steam that turns a turbine. Nine plants like this already exist in the in U.S.

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