Concentrating solar power systems (Solar Thermal Power systems) uses concentrated solar radiation as a high temperature energy source to produce electricity using thermal process.

In the first step it converts solar energy into heat energy, an incident solar irradiance is collected and concentrated by concentrating solar collectors or mirrors, and then generated heat is used to heat the thermic fluids such as heat transfer oils, air or water/steam, depending on the plant design. These fluids acts as heat carrier and/or as storage media. Further the generated steam or hot gases is used to operate a heat engine.

Solar collectors are used to produce heat from solar radiation. High temperature solar energy collectors are basically of three types:

1. Parabolic trough system: at the receiver can reach 400° C and produce steam for generating electricity.
2. Power tower system: The reflected rays of the sun are always aimed at the receiver, where temperatures well above 1000° C can be reached.
3. Parabolic dish systems: Parabolic dish systems can reach 1000° C at the receiver, and achieve the highest efficiencies for converting solar energy to electricity.

Barriers

1. Solar energy can be derived only during sunlight hours; it doesn’t work at night or in cloudy days; can be unreliable unless you’re in a very sunny climate.
2. Very expensive to build solar power stations.
3. Solar cells cost a great deal compared to the amount of electricity they’ll produce in their lifetime.
4. High capital cost.
5. The costs are however, coming down rapidly and is expected to be competitive by 2012.