One of the great things about concentrating solar power (CSP)—specifically solar thermal—technologies is their flexibility. While photovoltaics convert solar energy directly to electricity, solar thermal technologies like trough- or tower-based systems concentrate solar energy on a receiver, converting solar energy into heat. In that sense they operate like many conventional fossil fuel-based generating stations that use steam turbines to produce electricity. So it makes sense that by pairing a CSP system with an existing fossil fuel station overall emissions at such a station could be lowered while it could produce more power.

That’s the thought behind the Department of Energy’s recent announcement of $20 million to support such integration. “Today, between 11 gigawatts and 21 gigawatts of CSP could be built and integrated into existing fossil fuel plants in the United States, enough to power to between 3 million and 6 million homes,” DOE said in announcing the new awards being offered through its SunShot Initiative.

By marrying or partnering a CSP system with an existing fossil fuel generating station it leverages the infrastructure of the existing plant such as turbine and transmission systems, and it plays up the advantage of the solar systems, which produce the most energy when demand for energy is highest. Having such systems at the same site can also maximize performance from both so when the sun is covered by clouds, any additional generation needs can be met by ramping up production at the fossil fuel plant.

“CSP hybrid technology may help enable further cost reductions in stand-alone CSP projects and spur innovations across the broader concentrating solar power supply chain. The projects selected for funding under this program will work to design, build, and test cost-competitive integrated CSP-fossil fuel power generating systems,” DOE said.

For stand alone projects to be considered economically feasible, certain economies of scale generally need to be reached. That’s why projects like the Ivanpah Solar Electric Generating Station, are reaching into the 100s of megawatts and few smaller utility-scale systems are being considered. 

Already some instances of such hybrid systems have been completed or are underway in the U.S. For instance, Florida Power & Light has what was, when completed, the largest such hybrid system and one is being built by Areva Solar in Arizona, allowing the power plant there to produce more power than ever before.

Under this funding opportunity DOE seeks to support two to four hybrid projects. It’s seeking applications from industry, universities and national laboratories. “During the two- to four-year performance period, selected projects must pass reviews to continue advancing from the design phase through the construction and evaluation phases,” DOE said. The DOE will support up to 25 percent of the awardees’ project costs under the CSP HIBRED funding opportunity announcement.

(Photo courtesy of Areva Solar showing its CLFR technology)