dip a brush Into SUN and paint a window towards Eternity
Solar radiation falling on the earth’s surface consists of direct and a diffuse part. Solar PV utilizes both of the radiations and hence information of global insolation is required while installing such systems, but concentrated solar power systems as the name suggests concentrates the rays of the sun utilizing the property of the direct beam to focus it on a point or a line. Consequently sun trackers may be used to move the receivers so that maximum intensity can be utilized. Radiation is received over a large area and is directed on to a receiver using lenses and mirrors to a much smaller area and thus decreasing the losses and increasing both output and efficiency. According to design of the plant the temperature may have a range of 300°C to 1500°C.Heat collected in a plant is stored in various forms for later use and a plant may even use other sources of power generation like hydro or natural gas to generate energy at night or when the demand is high. Being a thermal power plant CSP’s generally require fluids for cooling purposes, but since water is scarce in desert areas, air may be used for cooling but it reduces efficiency and also increases the cost. CSP’s generally operate as a hybrid system utilizing air in winter and a combined cooling in summer to optimize the cost of running.
The CSP’s have very specific requirements due to the technology and the cost involved. The CSP’s require approximately 2 hectare (20,000 m²) in semi-arid and arid regions with clear skies which generally lies between 15°to 40° in both hemispheres. Before installation yearly direct insolation data is required and generally have a threshold value of 1900kWhr/m²/year to 2100kWhr/m²/year. An optimal generation capacity of a CSP is 200MW with the present tariff in Spain and France being around $209/MWhr (INR 10.5/kWhr) for generation, additional costs may be involved for transportation .
As Concentrated Solar Power Systems can only be installed at specific places therefore electricity generated may be transferred to different places using dedicated HVDC (High Voltage Direct Current) with very less losses.
Presently there is no CSP plant in India, but according to estimations the potential for the country in generating electricity from CSP is 11,000 TWh per year with over 112,497sq km potential area. The aim of JNNSM is to generate electricity 500 MW by 2013 and 10,000 MW by 2022. Currently 351 MW and 30MW power plants have been given a green signal in Gujarat and Rajasthan respectively .