One can choose to generate solar power through Photovoltaics (PV) or Concentrated Solar Power (CSP) technologies.
PV: Based on the ‘photovoltaic effect’ of semiconductors, PV cells generate power by converting solar irradiation to electrical direct current. Photons from sunlight impart energy to the semiconductor’s free electrons, bumping them up to the next energy level. The electrons now behave as charge carriers and their movement results in electric current. PV panels or modules are formed by connecting a number of cells to one another, which are then connected in multiples or arrays for large scale production.
The two PV modules in competition with each other are crystalline silicon (c-Si) and thin film. So far in India, thin film has been more popular due to the Domestic Content Requirement (DCR) lobbied on c-Si modules in phase one of the National Solar Mission (NSM). [Refer to the post ‘The Domestic Content Requirement (DCR) in India‘ to know more.]
India currently has a total grid installed PV capacity of 1,050MW, most of which has been installed in Gujarat and then Rajasthan. [Read BRIDGE TO INDIA’s November 2012 edition of the INDIA SOLAR HANDBOOK for more.]
CSP: CSP systems are used to convert solar irradiation to heat energy, which is then converted to electrical energy. The sun’s rays are concentrated onto a small area through reflection and refraction using mirrors and lenses, and the heat produced is used to power turbines (generally steam) which generate electricity.
Globally, PV technology is becoming more and more preferable to CSP due to the declining costs of PV modules and simpler technology, construction and maintenance. India, however, holds significant promise for CSP as it is believed that costs can be driven down to a notable extent. [Refer to a post ‘The CSP opportunity in India’ at the BRIDGE TO INDIA blog.]