VIENNA/LONDON (BLOOMBERG) - Solar and wind power could be in for another boost once policymakers begin accounting for the vast volumes of water needed to keep the lights on.
That is the conclusion of research published this week by the European Union's Joint Research Centre, which is urging the bloc's leaders to pay closer attention to the amount of water used by traditional coal, natural gas and nuclear power plants.
It takes more than 1,300 liters of water - enough to fill four bathtubs - to generate the electricity each European resident uses each day.
"For the EU, to decarbonise and increase the share of renewables of its energy supply, it needs to formulate policies that take the water use of energy sources into account," wrote the water and energy researchers led by Dr Davy Vanham. Solar, wind, geothermal and run-of-river hydropower account for a "small fraction" of water used compared with what is consumed by biofuels and traditional thermal plants, they said.
The findings focus attention on the rising competition for water resources between households, industry and agriculture. Exacerbating that friction is a string of heatwaves and lower rainfall levels that have prompted shutdowns at power plants across the continent during periods of peak strain.
Some of those incidents have been traced back to climate change. The issue has been replicated in the United States, India and China, underscoring how policies that touch on water, energy and food supplies tend to have impacts in all three spheres.
Coal, oil and nuclear plants account for about 30 per cent of the water needed to produce the electricity that Europeans consume. That compares with a 1.7 per cent share for all renewables combined, including solar, wind, geothermal and hydropower combined.
Reservoirs that rely on pumping water uphill, along with various forms of biomass have the highest reliance on water in the clean-energy sector.
"The choice of which renewables to promote is essential to alleviate water stress and maintain ecosystems and their services,'' according to the peer-reviewed paper published Oct 15. "Policies on future energy investments therefore need to consider which renewables have low unit water footprints."
Thermal power plants need water to cool reactions and use the steam to turn giant turbines for electricity. Solar panels and wind turbines can turn sunshine and air currents directly into electricity without producing the residual heat.
The researchers looked at energy consumption and generation data from the 28 EU nations, overlaid with information on climate change and water resources. They pinpointed areas in France, Poland and Spain where big power plants rely on large volumes of water.
"Recent summer droughts and heatwaves, such as in 2003, 2006, 2015 and 2018, which will only become more frequent due to climate change, have already led to water being a limiting resource for energy production throughout the EU," they wrote.
The full paper is titled "The consumptive water footprint of the European Union energy sector" and is available on the IOPscience website.