New Delhi: The ongoing COVID-19 pandemic has once again highlighted the vulnerability of our systems to unforeseen natural shocks and uncertainties. Given the importance of access to water and reliable power supply during the current lockdown, it is also timely to examine the uncertainties faced by India’s thermal power sector due to limited water availability, especially in water-stressed regions. In recent years, local water stress has resulted in loss of power generation in several states. In the past, Farakka thermal power station (TPS) in West Bengal, Raichur TPS in Karnataka, and Parli and Chandrapur TPS in Maharashtra have faced shutdowns due to water shortage. The crisis is especially aggravated during summers when rising power demand, due to increasing cooling needs, adds further load on thermal power plants. Monsoon failures and droughts add to the stress. Hence, the need of the hour is devising a robust long-term plan for sustainable water use in our thermal power
India’s water withdrawals for power generation are on the rise and in the absence of relevant policy measures to manage it sustainably, it is expected to quadruple by 2050. In water-stressed regions, limited water availability has often led to bitter conflict between farmers who need water for irrigation, domestic users who need water for day-to-day functioning, and the industrial users who need water for their production processes. In 2019 alone, approximately 36.5 billion cubic metres of
water was withdrawn in the country to cater to power needs of 1.33 billion people. A study by the Council on Energy, Environment and Water (CEEW) estimated that coal-based power plants, having a current share of 56 per cent within the overall generating capacity, require 3.8 litres of water on an average to generate one unit of electricity. Compared to this, gas and nuclear based power plants require around 1.6 litres and 6.4 litres of water per unit of electricity respectively. Among
renewables, solar photovoltaic systems require about 0.1 litres of water per unit for cleaning the dust off the panels.
While the latest National Water Policy is vague about water supply priorities, thermal power plants, known to be water guzzlers, have often been the first ones to be forced to stop power production. The coming together of local water stress, intense heatwaves, and technology-specific water consumption calls for long-term planning of the electricity sector, with a focus on sustainable and secure water usage.
Water optimisation for meeting the power demands
Policymakers must focus on a series of measures to scale up adoption of water efficient technologies in thermal power plants and introduce better water management practices.
First, robust water availability assessments must be conducted to avoid constructing and operating power plants in water-deficient regions. Power plants in major coal-bearing states like Chhattisgarh, Jharkhand, and Orissa are already facing difficulties due to non-availability of water.
Secondly, power plants must switch to efficient cooling technologies to reduce overall water-use. Adopting the recirculating cooling technology (from the once-through cooling system), as mandated by the Ministry of Environment, Forest and Climate Change (MoEFCC), will ensure that not more than 3 litres of water are consumed per unit of electricity produced. Further, CEEW analysis finds that effective implementation of the MoEFCC notification could reduce the power sector water withdrawals by 65 per cent by 2050 as compared to current levels. Hence, all Indian power plants must be nudged to switch to this technology as early as possible.
MoEFCC must also encourage power plants in drought prone regions to adopt dry cooling technology. While the capital cost of dry cooling technology is 1.5 to 3 times higher than recirculating technology, the key benefit is up to 85 per cent more water savings. China, Iran, South Africa, and several other countries have successfully promoted dry cooling technologies in water-stressed regions.
Finally, as mandated in the Revised Electricity Tariff (2016), treated wastewater from Sewage Treatment Plants (within 50 km) should be used for the cooling towers. This crucial intervention would reduce dependence on freshwater. CEEW’s analysis also finds that tariff for reused wastewater can be as low as INR 31 per kilolitre compared to fresh water which is charged at INR 65 per kilolitre for industries in some Indian cities. A current challenge though is that not many thermal power plants are located in the vicinity of a STP and therefore transporting water requires significant investment. Going forward, governments must build STPs in proximity to thermal power plants wherever possible to promote circular economy.
India’s economic and social ambitions for the coming decades are centred around equitable and reliable access of water and electricity to its citizens. Securing continuous water supply in an efficient manner for uninterrupted power generation would be a major step in this direction.