The report, entitled “Estimating the Value of Utility-Scale Solar Technologies in California Under a 40% Renewable Portfolio Standard”, finds that CSP, with its ability to store energy for several hours or more, helps to maintain firm capacity in the hours when the sun is below the horizon. This equates to an increase in value of 5 cents per kilowatt hour under a 33 percent renewable standard or 6 cents per kilowatt hour under a 40 percent renewable standard. This means that CSP can help to lower electricity bills.
“CSP adds significant additional value when compared to less flexible generation sources” said NREL CSP Group Manager Mark Mehos, co-author of the report with Jennie Jorgenson and Paul Denholm. “As the penetration of renewables rises, so does the relative value of CSP. CSP could also allow greater penetration of PV by making the grid more flexible and reducing curtailment of PV by generating energy after the sun sets. We intend to investigate this in more detail for the remainder of this year.”
CSP technologies concentrate the sun's energy and capture that energy as heat, which then drives an engine or turbine to produce electrical power. However, the thermal energy CSP generates can be held back for several hours via storage systems such as molten salts – and then used after the sun sets when demand is still high for, say, air conditioning, television, and lighting.
The report was funded through the Energy Department’s Office of Energy Efficiency and Renewable Energy in support of its SunShot Initiative. It compares the total operating costs of a system with and without an incremental amount of CSP with thermal energy storage or solar PV. It also analyses capacity value. The report is the second in a series of analyses of the value of CSP with thermal energy storage.
California is mandated to achieve 33 percent renewables within six years.
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