What is Concentrated Solar Power (CSP)?
Concentrated Solar Power (CSP) technologies produce electricity by concentrating the sun’s rays to heat a medium (usually a liquid or gas) that is then used in a heat engine process (steam or gas turbine) to drive an electrical generator. CSP uses only the beam component of solar radiation (direct normal irradiance), and so its maximum benefit tends to be restricted to a limited geographical range. [European Commission 2013a].
To concentrate solar radiation four designs are identified (see Figure 1):
Parabolic trough: Long rows of parabolic reflectors concentrate the sunlight 70 to 100 times onto a heat collection element (HCE) placed along the reflector’s focal line. The Sun is tracked around one axis, typically oriented north–south.
Linear Fresnel reflectors: The attraction of linear Fresnel is that installed costs on a m2 basis can be lower than troughs, and the receiver is fixed. However, the annual optical performance is lower than a trough reflector.
Central receivers (Solar towers): This technology uses an array of mirrors (heliostats), with each mirror tracking the Sun and reflecting its light onto a fixed receiver on top of a tower, where temperatures of more than 1 000 °C can be reached.
Dish systems: paraboloid-shaped and concentrate the sunlight onto a receiver mounted at the focal point, with the receiver moving with the dish. Dishes have been used to power Stirling engines at 900 °C, as well as to generate steam.
Figure 1: Layout of different Concentrated Solar Power configuration
According to the German Aerospace Centre (DLR), potential of electricity produced by CSP in Europe is around 1500 TWh/year being the Mediterranean countries those with the highest potential according to their available radiation (over 2000 kWh/year). The global installed capacity could reach 150 GW by 2020, with an average capacity factor of 32 %. [IRENA 2013]
CSP employed 22 000 people worldwide in 2014, 15 000 in the case of Europe [Ferroukhi et al. 2015]. In the period 2015-2030, the solar thermal electricity is expected to create up to 150,000 qualified jobs including engineering, development and financing, manufacturing, construction and operation and maintenance [Estela 2016].
The potential technology deployment is supported by national policies. Thus, six EU countries have reflected CSP in their National Renewable Action Plans (NREAPs): Cyprus, France, Greece, Italy, Portugal and Spain. So, despite economic environment is expected a technology spread in the coming years. [SETIS 2013]
Further information on CSP can be found at the Strategic Energy Technologies Information System (SETIS): https://setis.ec.europa.eu/technologies/concentrated-solar-power
References [European Commission 2013a] European Commission: Concentrating Solar Power (76). DOI:10.2172/939307 [IRENA 2013] IRENA: Concentrating Solar Power. Renewable Energy 1 (331–339). DOI:10.1063/1.2993731 [Estela 2016] ESTELA: STE CREATES JOBS IN EUROPE. URL: http://www.estelasolar.org/ste-means-jobs-and-green-growth/ste-creates-jobs-in-europe/ [SETIS 2013] SETIS: Concentrated solar power (1–18)