Picking Winners
Sempra Generation, the unregulated, power plant – operating subsidiary of San Diego – based Sempra Energy, has developed a solar project that’s an exemplar for the power industry: the 10-MW El Dorado Energy solar facility (El Dorado), which shares its plant name with a gas-fired plant. The solar facility is the largest thin-film PV project in the U.S. and is located 40 miles south of Las Vegas, adjacent to Sempra Generation’s 480-MW gas-fired combined-cycle power plant. The combined plant sells its energy into the wholesale power markets of the Southwest (Figure 1).
1. Desert denizens. Sempra’s El Dorado Energy consists of a 480-MW gas-fired combined-cycle plant and a 10-MW photovoltaic (PV) plant. The PV portion of the plant was designed in 1-MW blocks that terminate at one of the 10 small white buildings that contain the panel terminations, two inverters, and a transformer to produce electricity at 4,160 V. All the electricity produced by the plant is then terminated in the switchgear at the power plant. Courtesy: Sempra Generation
El Dorado is unique in that it takes advantage of the synergy possible between a PV project and a combined-cycle plant. Crystalline silicon panels (thin film), in general, cost more to make because silicon is expensive, but they also can convert sunlight into electricity at higher rates than competing PV technologies (Figure 2).
2. One-man show. Only one member of the El Dorado Energy plant staff is assigned full-time PV system responsibility. Courtesy: Sempra Generation
Sempra picked First Solar to supply the PV system for El Dorado. First Solar, located in Tempe, Ariz., was selected because it could inexpensively supply its cadmium-telluride panels and because the company is rapidly expanding its factories in the U.S. and Malaysia to reduce costs. First Solar manufactured the solar modules and was the engineering, procurement, and construction (EPC) contractor for the project.
PV Projects Heat Up
El Dorado is Sempra Energy’s first solar power generation project but will likely not be its last. "This new solar project is another step in Sempra Generation’s long-range plan to emerge as a leading renewable-energy developer," said Michael W. Allman, president and CEO of Sempra Generation at the plant’s dedication. "The combination of Sempra Generation’s experience in developing power-generation projects in the region with First Solar’s expertise in advanced, thin-film photovoltaic solutions is a natural fit. We look forward to helping the region’s utilities meet state requirements calling for them to include solar, wind and other renewable energy sources in their power portfolios."
Michael Gallagher, vice president of asset management, is responsible for all of Sempra Generation’s fleet of fossil and renewable energy projects. Gallagher told POWER during a plant visit in late October that El Dorado was constructed in only six months. The installation of more than 167,000 solar modules on 80 acres of desert property began in July 2008 and was completed in December 2008. The property is also designated as a renewable energy zone and is leased from Boulder City. The new project’s entire 10-MW output has been contracted under a 20-year power purchase agreement with Pacific Gas and Electric. Although this arrangement seems out of the ordinary, PG&E submitted the best bid price when Sempra offered the merchant renewable energy for sale.
Gallagher did not wish to release the final construction cost of the project, but we can estimate the cost from other sources. The Energy Information Administration (EIA) estimates the cost to install a typical utility-scale PV plant at just over $6,000/kW, and a Lawrence Berkeley National Laboratory (LBNL) report includes a breakdown of installed cost estimates for the largest PV projects now operating in the U.S. The LBNL report notes that the installation cost of El Dorado was a rock-bottom $3.2/WDC, lowest of all the reported systems for the 12,600 kVDC system (10 MW nominal) by a margin of about 40%. If the LBNL estimates are good, then Sempra installed El Dorado for about $40 million, or $4,000/kW.
Gallagher did confirm that he expected El Dorado would finish the year with a capacity factor of 25%. Reasonable economic assumptions suggest that the plant should produce electricity for about $0.20/kWh, ignoring the system’s ongoing maintenance costs, although that number could not be confirmed.
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