Few days back, I got a chance to attend a webinar on ‘Water Risk for India’s Solar Power Sector’. The webinar was organized by ET Energy World and presented by Vinay Rustagi (Managing Director, Bridge To India). After attending webinar, I got to know that water management at solar power plants has been one of the least explored areas in terms of policy framework. Current scenario of solar power plants in terms of water availability and its usage makes it important to address the issue on priority basis. Before I share excerpts from webinar, let me give you brief background of water usage at solar power plants. The full length video of webinar is attached at the end of blog post.


    Solar modules require periodical cleaning in order to avoid soiling effect (accumulation of dust, pollution, bird droppings on module surface) on power generation. 3 to 6 per cent annual generation loss has been estimated due to soiling. However, periodical cleaning (mostly twice in a month) can reduce this generation loss up to 1%.

india solar power water cleaning tractor
Image: Tractors are used at some solar power plants to carry water from reservoir to plant

    According to a survey conducted by Bridge To India, 1.5 to 4.5 litres of water is consumed per module per cleaning cycle. This requirement is still only 5 % to that of thermal power plants. Since most of the solar power plants are located in dry areas, water availability at plant level is taking new twists and turns with every passing year.


  • Solar power plant installation is concentrated in certain states of the country. As on June 30, 2018, Top 5 states contribute to 70 per cent of total installed capacity of solar power. Almost 94% of solar capacity in India is exposed to medium-high level of water risk.
  • At least 18% of India’s installed capacity is exposed to extremely high levels of water risks. Solar power plants contributing to around 38% of India’s installed capacity are located in high water risk zones. Yet another 38% fall under medium to high risk category.
  • Cost of cleaning is 25 to 30 % of O&M cost (excluding insurance cost) if surface water is used. It is reduced to 14 to 22 % if ground water is used.
  • 60% of water used for cleaning is taken from ground whereas remaining 40% is taken from nearby surface water sources (river, lake, etc). In case of ground water, cost of module cleaning primarily depends on labour cost and ranges from INR 42,000-66,000/ MW per year. In parts of Rajasthan, water cost has almost doubled in the last 3-4 years due to sharp increase in demand.
  • Developers are preferring robot cleaning and anti-soiling coatings as a solution to rising water issues. Robotic cleaning with payback period of 2-3 years can reduce water consumption by 50-100%. Solar power developers are looking for commercially proven integrated anti-soiling coated modules with complete lifetime warranties. When integrated anti-soiling coated modules are used, water consumption is reduced by up to 35-50% in addition to the 1-2 % more power generation.


     The information presented is pretty enough to conclude that necessary steps are required to be taken to address rising water risks of Indian solar power plants. Solar community should develop guidelines for optimum water usage at plants using extensive ground level experience of operators.

    Any additional cost is incurred in implementing environmental-friendly decisions should be considered by government while executing solar PV auctions (for example, by relaxing maximum tariff of PPA). This will not only help in maintaining higher power generation from solar PV in future but also ensure balanced water reserves in areas around solar power plants.

Full fledged report by Bridge To India can be accessed here.

Source: Bridge To India