In Focus: Solar Thermal Systems

In Focus: Solar Thermal Systems

Solar Photovoltaic (PV)

  • Solar Photovoltaic (PV) is a technology that converts sunlight (solar radiation) into direct current electricity by using semiconductors.
  • When the sun hits the semiconductor within the PV cell, electrons are freed and form an electric current.
  • Solar PV technology is generally employed on a panel (hence solar panels).
  • PV cells are typically found connected to each other and mounted on a frame called a module.
  • Multiple modules can be wired together to form an array, which can be scaled up or down to produce the amount of power needed.
  • Solar PV, therefore, works best where there is lot of sunlight.


Solar Thermal Systems

  • Solar thermal technologies capture the heat energy from the sun and use it for heating and/or the production of electricity.
  • This is different from photovoltaic solar panels, which directly convert the sun’s radiation to electricity
  • Solar thermal technology is employed on ‘collectors’ and are measured in terms of square metres.
  • They come in different forms, but primarily, as tubes, flat plates or reflectors that focus sunlight on to a heat-picking ‘thermic fluid’.
  • 100 sq m of collector area can generate heat energy of 40 kW, and costs about ₹7.5 lakh. However, to generate 40 kW of electric energy it would cost some ₹20 lakh with coal and diesel.


  • Solar water heaters
  • For cooking meals
  • For drying paints etc

Tepid Adoption

  • Adoption of solar thermal has been tepid, relative to its potential because the earlier systems were expensive and the bang they gave vis-a-vis the incumbent, fossil-fuel based systems was not that high and also it faced a huge competition with Solar PV.


  • Focus by the Government: The government should also pay solar thermal as much attention as solar PV and to simplify the complex subsidy scheme so that it is given to Indian manufacturers, in order to encourage local production rather than in China.
  • Promotion of SHIP (Solar heating for industrial processes): A move to convince the industry to adopt solar thermal has emerged in the form of a ‘solar payback project’, funded by the German ‘International Climate Initiative’, which aims to promote SHIP in India, South Africa, Mexico and Brazil.
  • Opex model: The Model in which comapies own the equipment and the user industry pays only for the heat delivered. It is already common in solar PV, the ‘opex model’ is beginning to happen in thermal, but it needs financial fuel for growth.



Section : Environment & Ecology