Concentrating solar power (CSP), particularly thermal solar power, has a distinct advantage over photovoltaics in that the energy the systems use to produce electricity is thermal energy, which can be stored as opposed to photovoltaics, which convert photons directly into electricity. The thermal energy is easier to save as energy in the form of heat, which can then later be converted into electricity as needed. That’s one of the reasons why CSP can offer more economically reliable energy than some other forms of renewable energy.

To help explain this, the Concentrating Solar Power Alliance (CSPA) held a Webinar and subsequently released a report: “The Economic and Reliability Benefits of CSP with Thermal Energy Storage: Recent Studies and Research Needs.” The CSPA is an industry group consisting of BrightSource, Abengoa, Cone Drive Gearing Solutions, Lointek, Torresol Energy, and Wilson Solarpower. The report actually looked at a larger cross-section of reports conducted by the national energy labs and academic institutions in an attempt to help regulators and utilities understand the value that CSP with storage offers. “This report comes at a time when utilities and grid operators are evaluating the true cost and operational impacts of higher penetrations of variable resources,” said Tex Wilkins, Executive Director of the CSP Alliance.

“The purpose of this report is to synthesize the current study findings and identify some additional research needs.  A robust body of research is available and demonstrates that CSP with storage provides additional economic and reliability value to utilities and grid operators when compared to other renewable investments,” said Dr. Udi Helman, Director of Economic and Pricing Analysis, BrightSource Energy. 

The report explains how CSP with thermal storage allows grid operators avoid many of the intermittency issues with other renewables like wind and photovoltaics. Since the thermal storage capability can be used to generate electricity for hours when the sun’s not shining. CSP can also be integrated with other systems to either enlarge their generating capacity or operate as a hybrid system where a natural gas generator, for instance, can provide backup power when needed.

The report cites research that shows at low renewable penetration levels, thermal storage adds energy and ancillary service value to a CSP plant in the range of $5 to $10 per megawatt hour. The rate varies based on the region studied and type of CSP and storage technologies being deployed. At higher penetration levels, the value of CSP with thermal story could increase significantly, up to $30 per megawatt hour, particularly  in regions with high solar thermal potential.