Sempra Generation believes in solar power’s bright future: The dust had barely settled at the company’s five-month-old 10-MW photovoltaic power generation plant near Boulder City, Nev., when it announced an expansion to quintuple capacity. The company claims it will create North America’s largest thin-film photovoltaic installation.

Photo: First Solar

Solar plant is next to Sempra’s 480-MW gas-turbine plant.

The unit of San Diego-based Sempra Energy “won’t start construction until we have a [power sales] contract in hand,” says a Sempra spokesman. “We hope to start construction later this year.”

Potential buyers could come from neighboring states, all of which have renewable-portfolio standards. The existing facility, El Dorado Solar Energy, is built on 80 acres of desert land ground-leased from Boulder City. The installation consists of 167,000 thin-film PV panels mounted to stationary space frames anchored by light-gauge steel pilings. Tempe, Ariz.-based First Solar Inc., the original engineering-procurement-construction contractor, is reprising its EPC role for the expansion.

“Thin films are about 50% less efficient than conventional silicon solar panels,” says Joe Verrengia, a spokesman with the National Renewable Energy Laboratory, Golden, Colo. “The potential advantage lies in reducing materials and manufacturing costs.”

First Solar’s manufacturing costs are 93¢ per watt, roughly half the production cost of silicon panels, say company officials. “This would be our largest renewable energy project thus far,” says Sempra Generation President and CEO Michael W. Allman. Sempra aims to be the first U.S. company to own 500 MW of solar-generating capacity.