Concentrated Solar Power Technologies

Solar energy can be tapped to produce electricity in two distinct ways. One is using a photovoltaic system that uses sunlight as it is and the other is by using solar concentrators. The basic idea is to translate the sun's energy in the form of impending photons to usable electricity.

Fig. Prominent CSP Technologies [1]

Solar Concentrators, such as that used in Concentrated Solar Power (CSP), can be used to concentrate sunlight to be used either in a Photovoltaic (PV) system or a solar thermal system. Though these two technologies essentially use focused solar light to produce electricity, they differ in the way sunlight is converted to electricity. In the case of a photo-voltaic device, the focused light is converted to electricity by exploiting the electronic properties of semiconducting materials, whereas in the case of solar thermal, the focused light heats up a transport fluid which is then used to generate steam which drives a turbine using the Rankine cycle generator. Whereas PV commonly uses the visible to UV part of the spectrum to generate electricity, solar thermal uses the infrared energy to heat the Heat Transfer Fluid (HTF).

Concentrated Solar Power is used to produce electricity called solar thermoelectricity, usually generated through steam. Basically CSP technology uses mirrors with tracking systems to focus a large area of sunlight onto a small area. The concentrated light then causes a thermal storage material like oil, salt or water to heat. This heat is then used as a heat source for a conventional power plant. The solar concentrators used in CSP systems can often also be used to provide industrial process heating or cooling, such as in solar air-conditioning.

To explore the energy storage that is possible using concentrated solar collector technology, it is necessary to briefly visit the different solar harnessing technologies being used today. CSP is seen as a holistic technology with other benefits as well involving the use of the waste heat from power generation.  

References

[1] C. Sharma, A.K. Sharma, T.K. Aseri, S.C. Mullick, T.C. Kandpal, Solar thermal power generation, in: P. Saxena, H.P. Garg, O.S. Sastry, S.K. Singh (Eds.), Adv. Sol. Energy Sci. Eng., Today & Tomorrow’s Printes and Publishers, New Delhi - 110 002, India, 2015: pp. 89–153.