Concentrated solar power (CSP, also known as concentrating solar power, concentrated solar thermal) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight into a receiver. Electricity is generated when the concentrated light is converted to heat (solar thermal energy), which drives a heat engine (usually a steam turbine) connected to an electrical power generator or powers a thermochemical reaction.
As of 2021, global installed capacity of concentrated solar power stood at 6.8 GW. As of 2023, with the inclusion of three new CSP projects in construction in China and in Dubai in the UAE, the total is now 7.5 GW. The US National Renewable Energy Laboratory (NREL) maintains a full database of the current state of all CSP plants globally, whether under construction, shut down, or operating. The data includes comprehensive details such as capacity, type of power block components, number of thermal energy storage hours, and turbine sizes.
As a thermal energy generating power station, CSP has more in common with thermal power stations such as coal, gas, or geothermal. A CSP plant can incorporate thermal energy storage, which stores energy either in the form of sensible heat or as latent heat (for example, using molten salt), which enables these plants to continue to generate electricity whenever it is needed, day or night. This makes CSP a dispatchable form of solar. Dispatchable renewable energy is particularly valuable in places where there is already a high penetration of photovoltaics (PV), such as California, because demand for electric power peaks near sunset just as PV capacity ramps down (a phenomenon referred to as duck curve).
CSP is often compared to photovoltaic solar (PV) since they both use solar energy. While solar PV experienced huge growth in recent years due to falling prices, solar CSP growth has been slow due to technical difficulties and high prices. In 2017, CSP represented less than 2% of worldwide installed capacity of solar electricity plants.