Which produces the cleanest form of energy — windmills or solar photovoltaic plants? Experts say wind turbines produce cleaner energy than solar PV plant as it does not re-quire water for any purpose. Windmills do not need water in the process of wind power generation. “Velocity of wind is used and converted into the electrical energy. In the process, you don’t need water for any purpose. It is also the cleanest source of energy because it does not emit any harmful gas,” Indian Wind Power Association chairman Prof Dr K. Kasturirangaian told DC.
However, he said Solar PV plant requires water for cleaning at least once in a week. The PV panels should be cleared of dust for better efficiency, he said. In a water scarce state like Tamil Nadu, he said that wherever wind is available, windmills should be preferred and in other places, solar power should be established. Solar power plant in Indian conditions requires about 5,000 litres per mega watt per wash, which happens once in a week. The renewable energy sources like wind and solar do not only help cut down on the carbon emissions but also significantly help reduce water usage for the energy generation through fossil fuels like coal and gas.
Unlike renewable energy, the coal based thermal power plant, which produces highly polluted energy, consumes 4,000 to 5,000 litres of water per MW per hour. The nuclear power plant consumes much higher volumes of water. A senior official of National Thermal Power Corporation said that revised environment norms for thermal power plant on water consumption, if implemented, would drastically bring down water requirement. The norms will require all fresh water based once-through-cooling (OTC) system plants to install water-efficient cooling towers that consume up to four cubic metre per watt hour (m3/MWh). Furthermore, existing cooling tower-based plants will need to restrict water consumption to 3.5 m3/MWh and plants that will be set up after January 2017 have to achieve 2.5 m3/MWh.