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Fourth CSP Plant Receives DOE Loan Support

June 3, 2011

The U.S. Department of Energy (DOE) announced on May 19 the offer of a conditional commitment for a $737 million loan guarantee to support the Crescent Dunes Solar Energy Project—a 110-megawatt (MW) concentrating solar power (CSP) plant in south-central Nevada. The project is one of four CSP plants under development to benefit from such guarantees from the DOE Loan Programs Office. After all four plants are built and operating, their combined power-generating capacity will approach 1,500 megawatts (MW).

SolarReserve, LLC, is the sponsor of the project, to be located 14 miles northwest of Tonopah, Nevada, on 2,250 acres leased from the Bureau of Land Management (BLM). The company anticipates the facility will create 600 construction jobs and 45 operations jobs.

Plans for Crescent Dunes include as many as 17,500 heliostats, or specialized mirrors, that will focus the sun's thermal energy onto a 640-foot-tall solar power tower, where molten salt will be heated. The heated salt is delivered to a hot storage tank where it is subsequently used to generate steam to drive a steam turbine that generates electricity. In addition, the stored salt can be used to generate steam for as much as 10 additional hours, permitting steady, uninterrupted power during peak electricity demand, despite cloud cover, and even at night.

This thermal storage system increases grid stability and reduces the need for carbon-pollution-emitting generators, which currently supplement intermittent renewable generation technologies during periods of no or low solar resource. The molten salt technology was previously tested and demonstrated at the Solar Two CSP facility, in south-eastern California, in conjunction with DOE’s Sandia and National Renewable Energy Laboratories.

Crescent Dunes is expected to avoid nearly 290,000 tons of carbon pollution annually, or the equivalent of 20 percent of the annual generation of an average coal-fired plant in the United States. The project is also expected to produce approximately 500,000 megawatt-hours (MWh) annually, enough to power more than 43,000 homes. Power from the project will be sold to Nevada Power Company, a utility subsidiary of NV Energy, Inc. and will help NV Energy meet its Renewable Portfolio Standard goals for Nevada, as well as its evening load requirements.

Previous to the Crescent Dunes announcement, DOE announced on April 18 that the Blythe Solar Power Project would receive a conditional loan guarantee for $2.1 billion for a parabolic-trough CSP facility. Sponsored by Solar Trust of America, LLC, the Blythe project received the loan guarantee to support Units 1 and 2 of the facility, which combined will have a 484-MW generating capacity. The facility will be located adjacent to the City of Blythe in Riverside, California, and is expected to create more than 1,000 jobs.

Parabolic trough systems collect the sun's energy using long, rectangular, U-shaped mirrors to focus the sun onto tubes (or receivers) that run the length of the mirrors. The reflected sunlight heats a fluid flowing through the tubes. Then the fluid is piped to a system where the heat is transferred to water, making steam, for use in a steam turbine system that generates electricity.

Units 1 and 2 of the Blythe project comprise the first phase of a larger project that, when completed, will generate 1,000 MW of solar power. Units 1 and 2 will include HelioTroughT collectors, which feature a larger yet simplified design than earlier trough technology, making them less expensive to build and install, and more efficient. The project will be the first CSP parabolic trough plant to use an air-cooled condenser unit, which will decrease water use by nearly 90 percent compared with a water-cooled CSP facility. The project will sell all of its electricity output to Southern California Edison and will deliver power into the California Independent System Operator power grid.

Also in April, the Ivanpah Solar Energy Generating System in the Mojave Desert in California received a $1.6 billion DOE loan guarantee for its three power tower CSP plants. Combined, the solar complex is expected to generate 392 gross MW of electricity using the company's proprietary CSP technology that was developed by the project’s sponsor, BrightSource Energy. Once operational, the project will produce nearly 1 million megawatt hours of electricity per year, enough to power more than 85,000 homes, and will avoid more than 640,000 tons of carbon dioxide annually, equivalent to taking more than 120,000 cars off the road.

The project includes solar fields on which 173,000 dual-mirror heliostats will operate. BrightSource's proprietary technology controls the mirrors so they follow the sun. Electricity from the project will be sold under long-term power purchase agreements with Pacific Gas & Electric and Southern California Edison Company (SCE). The project will be interconnected to the electricity grid via an upgraded SCE transmission line. (See a related story published October 19, 2010 on the NREL CSP Research website.)

In July 2010, DOE offered the first of the CSP loan guarantees to the Solana Generating Station. That project, located near Gila Bend, Arizona, is planned to be a 280-MW parabolic trough solar plant that is expected to generate enough power to supply 70,000 homes under a 30-year power supply contract with Arizona Public Service (APS). Abengoa Solar will construct, own, and operate the facility. An unspecified heat-storage technology will provide 6 hours of generating capacity after sunset. During three years of construction, the project is expected to employ 1,500 workers at the 1,900-acre site. After completion, Solana will employ 85 permanent workers. APS says The Solana Generating Station will cover 3 square miles and contain 2,700 parabolic trough collectors. Located on what is currently agricultural land, the power plant will use 75 percent less water than the current use of the property, according to APS.

For more information, see the DOE press releases about the loan guarantees for the Crescent Dunes, Blythe, Ivanpah, and Solana projects.

In addition, see basic information about concentrating solar projects in the United States on the NREL CSP Project website.