Concentrated solar power (CSP), also known as solar thermal electricity, has been around since the 1980s. Instead of converting sunlight directly into electricity like photovoltaics (PV) do, it relies on the core technology of fossil-fuel generation: steam turbines. The difference is that rather than using coal or natural gas, CSP uses solar radiation as its primary fuel—free and clear of carbon.
Mirrors, the essential component of any CSP plant, are curved or angled in specific ways to concentrate incoming solar rays to heat a fluid, produce steam, and turn turbines. Because CSP relies on immense amounts of direct sunshine, it is best suited to hot, dry regions where skies are clear.
A critical advantage of CSP is energy storage. Unlike PV panels and wind turbines, CSP makes heat before it makes electricity, and heat is easier to store. When equipped with molten salt tanks for heat storage, CSP plants can continue to produce electricity well after the sun goes down.
As of 2014, CSP was limited to just 4 gigawatts worldwide. As the technology becomes more effective and less expensive, the central benefit of reliability will hasten its growth.
“tale of two countries, Spain vs. the U.S.”: IEA. Technology Roadmap: Solar Thermal Electricity. Paris: International Energy Agency, 2014.
California in the 1980s: Perlin, John. Let It Shine: The 6,000-Year Story of Solar Energy. Novato, California: New World Library, 2013.
2014…4 gigawatts worldwide: IEA. Solar Thermal.
[generation] in Spain: IEA. Solar Thermal.
Morocco…Noor Ouarzazate Solar Complex: Nelsen, Arthur. “Morocco to Switch on First Phase of World's Largest Solar Plant.” The Guardian. February 4, 2016; Hicks, Celeste. “Morocco Lights the Way for Africa on Renewable Energy.” The Guardian. November 17, 2016.
direct normal irradiance…latitudes: IEA. Solar Thermal.
Optimal locales [for CSP]: IEA-ETSAP and IRENA. Concentrating Solar Power—Technology Brief. Paris and Abu Dhabi: International Energy Agency Energy Technology Systems Analysis Programme and International Renewable Energy Agency, 2013.
Mediterranean basin…Kalahari Desert…potential: Pfenninger, Stefan, et al. “Potential for Concentrating Solar Power to Provide Baseload and Dispatchable Power.” Nature Climate Change, 4, no. 8 (2014): 689-692.
heat can be stored…more cheaply: Romm, Joe. “Why You Should Be Paying Attention to the ‘Other’ Form of Solar Power.” Think Progress. June 10, 2015.
Efficiency of…[t]echnologies…under development: Barbee, Jeffrey. “Could This Be the World’s Most Efficient Solar Electricity System?” The Guardian. May 13, 2015.
Solar Reserve…strategy to stop bird deaths: Kraemer, Susan. “One Weird Trick Prevents Bird Deaths at Solar Towers.” Clean Technica. April 16, 2015.
[History of using] mirrors to start fires: Perlin, Shine.