Sempra Generation will turn up juice with expansion of solar-power ...

"We won't start construction until we have a contract in hand," Sempra spokesman Art Larson said. "We're talking to a number of utilities and potential customers to gauge their interest in the facility. We hope to start construction later this year."

Buyers could come from California and also Arizona, which seeks a 25 percent renewable benchmark by 2025. Nevada similarly wants 20 percent of its power to come from renewable resources by 2025, with 5 percent originating from solar.

Sempra's existing facility, El Dorado Solar Energy, rests on 80 acres of desert land ground-leased from Boulder City for 20 years. It's next to parent Sempra's 480-megawatt natural gas-fired, combined-cycle El Dorado Energy power plant that opened in May 2000, which means transmission lines are already in place. The installation consists of 167,000 thin-film photovoltaic panels mounted to stationary space frames anchored by light-gauge steel pilings. First Solar Inc., which built the original facility, is returning for the expansion. The Tempe, Ariz.-based company will serve as engineering, procurement and construction contractor, and oversee its operations when complete.

Plans call for another 830,000 thin-film photovoltaic panels, generating 48 megawatts, on 380 acres designated as a renewable energy zone by Boulder City. The project will create about 200 construction jobs. Panels measure 3.6 feet long by 2 feet wide and weigh 26.5 pounds; there are 15 panels per frame. Construction entails drilling 100,000 pilings. Sempra is self-financing the project and did not disclose costs; it's also taking advantage of a 30 percent federal investment tax credit. The combined 58-megawatt, 997,000-panel facility, renamed Copper Mountain Solar, is expected to begin service by late 2010.

"Thin films are about 50 percent less efficient than conventional silicon solar panels, and require twice as much space to generate the same amount of power," said Joe Verrengia, a spokesman with the National Renewable Energy Laboratory in Golden, Colo. "The potential advantage lies in reducing materials and manufacturing costs."

First Solar uses cadmium telluride and sulfide semiconductor material with an assembly-line production process that lowers manufacturing costs to 93 cents a watt. It's roughly half the production cost of silicon panels, say company officials. Panels, which have a 25-year life span, can be produced within 2.5 hours. They yield a 10.9 percent conversion rate from sunlight into energy.

Acciona, by comparison, achieves a 25 percent conversion rate at its 64-megawatt solar power plant, which is also near Boulder City. The 2-year-old Nevada Solar One facility uses concentrating solar thermal technology. Roughly 190,000 curved parabolic mirrors concentrate sunlight to 750-degrees Fahrenheit to heat synthetic oil inside tubes that create steam and drive turbines to produce electricity. Acciona currently has a 40-year ground lease with Boulder City to occupy 350 square acres in the Eldorado Valley. The city receives about a $1 million annually in rent payments between Acciona and Sempra.

PowerLight, meanwhile, achieves a 25 percent conversion rate at its 14-megawatt photovoltaic installation at Nellis Air Force Base. The Solar Star facility, opened in 2007, uses 72,000 photovoltaic monocrystalline wafer panels containing nearly 6 million solar cells. It uses a tracking technology that rotates photovoltaic panels throughout the day to follow the sunlight. Solar Star consequently achieves a conversion rate that is 10 percent higher than the industry average, PowerLight CEO Thomas Werner claims.

Photovoltaic film, however, like the kind found at El Dorado Solar Energy, is lightweight and can be manufactured in large quantities using methods similar to newspaper printing, officials say. Panels use layers of layers of semiconductor materials only a few micrometers thick; they require only a tiny fraction of the materials found in conventional cells. It makes thin film cheap, quick and easy to mass-produce.

"Researchers and manufacturers are looking at each step in the process to squeeze efficiencies, boost scale and go faster," Verrengia said. "Thin films also can be manufactured in more conventional industrial conditions. And rather than being built into rigid panels, they can be incorporated onto inexpensive and conventional building materials such as glass or metal. This integrated approach also has aesthetic advantages because the thin films can be installed flush into roofs, windows and walls."

Contact reporter Tony Illia at tonyillia@aol.com or 702-303-5699.
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