Just days before the Energy Department’s advanced energy loan guarantee program funded under 2009 stimulus law is set to expire—and amid an investigation of Solyndra, the California-based solar manufacturer that received the Obama administration’s first loan guarantee—the DOE today finalized a $737 million loan guarantee for the development of a 110-MW concentrating solar power tower facility in Nevada.

The funding backs Tonopah Solar Energy’s Crescent Dunes Solar Energy Project. The solar power tower will use molten salt as the primary heat transfer and storage medium. Located 14 miles northwest of Tonopah, Nev., on land leased from the Bureau of Land Management, project-sponsor SolarReserve has said the facility will be the “first of its kind” in the U.S. and the tallest molten salt tower in the world.

“If we want to be a player in the global clean energy race, we must continue to invest in innovative technologies that enable commercial-scale deployment of clean, renewable power like solar,” Energy Secretary Steven Chu said toda. “Solar generation facilities, like the Crescent Dunes Solar Energy Project, help supply energy to local utilities and create hundreds of good, American clean energy jobs.”

The project includes 17,500 heliostats that collect and focus the sun’s thermal energy to heat molten salt flowing through an approximately 640-foot tall solar power tower. The high temperature molten salt circulates from the tower to a storage tank, where it is then used to produce steam and generate electricity. Excess thermal energy is stored in the molten salt and can be called upon at any time to create additional steady, clean, renewable power for up to ten hours, even in the evening hours and when direct sunlight isn’t available.

“This 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 DOE said in a statement. The molten salt technology was demonstrated at the Solar Two facility in conjunction with the DOE’s National Renewable Energy Laboratory. Power from the project will be sold to Nevada Power Co., a utility subsidiary of NV Energy, Inc.

The DOE, which has to date issued loans, loan guarantees, or conditional commitments for loan guarantees worth nearly $40 billion to more than 40 clean energy projects across the nation, is rushing to meet the program’s impending deadline. It hopes to make a final decision on about 10 other projects by Sept. 30.

The approvals have sparked the ire of Congressional Republicans, who have raised concerns that DOE may rush final reviews of projects under consideration. The DOE has said it will not approve any projects without a detailed analysis.

Republicans on both the House Oversight and Government Reform and the Energy and Commerce committees have launched investigations into the agency’s loan-gurantee program after Solyndra, which received $535 million loan guarantee from the DOE, filed for bankruptcy and laid off 1,100 workers earlier this month. The Justice Department and other federal agencies are also investigating the failed solar manufacturer.

Last week in a House hearing, Republicans on the committees asked Solyndra CEO Brian Harrison and Chief Financial Officer W.G. Stover questions such as when taxpayers might expect to get back the $535 million that the federal government loaned the firm as part of the stimulus program.

But the executives from the Fremont company repeatedly invoked their Fifth Amendment rights against self-incrimination. After several minutes of similar questions and responses, Rep. Henry Waxman (D-Calif.) said pushing witnesses pleading the Fifth bordered on prosecutorial misconduct, ending the hearing shortly thereafter.

Sources: POWERnews, DOE, House Oversight and Government Reform Committee