Solar future in San Luis Valley continues to shine

T. Dix

Cogentrix plant in San Luis Valley

On Monday, the Saguache County Commissioner gave local approval for a sprawling solar complex proposed by Santa Monica, California-based SolarReserve and now comes word that the solar plant being built near Alamosa by North Carolina-based Cogentrix LLC is nearing completion.

“We are expecting to take power from the plant this quarter,” said Gabriel Romero, a spokesman for Energy, which has an agreement with to buy the plant’s power for 20 years.

Reserve and Cogentrix are both “concentrating” technologies but the similarity stops there. SolarReserve is proposing placing special sun-tracking mirrors – called heliostats—on 3,400 acres to focus the sun’s heat at two, 656-foot-tall towers holding molten salt reservoirs. The hot molten salt is used to heat water to turn a steam turbine.

Congentrix uses lenses to focus the sun’s rays on photovoltaic cells – but these cells are more akin to the high-performance, high-expense solar panels used in space craft. While the average solar panel converts between 16 percent and 20 percent of the sun’s light into electricity, Cogentrix says that its efficiency is around 40 percent.

Another very big difference is that Cogentrix, which is a subsidiary of the investment bank Goldman Sachs, has a 20-year contract to sell the power from its 30 megawatts facility to Xcel Energy.

The initial estimate of the plant’s cost was between $140 million and $150 million. The project received a $91 million loan guarantee from the US Department of Energy.

The facility is expected to produce enough a year to power more than 6,500 homes and will avoid the emissions of more than 43,000 metric tons of carbon dioxide a year, according to the Department of Energy.

SolarReserve is still looking for a customer and some additional transmission capacity to get all of its 200 megawatts out of the valley. But if the complex is built it would among the largest of its kind in the US. And when switch on the Congentrix plant is thrown, it will be the largest concentrating photovoltaic plant in the world.

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