Energy production, both in terms of clean tech and fossil fuels, accounts for 15pc of the world’s total water use, a report from the International Energy Authority (IEA) suggests.
Ahead of World Water Day on 22 March, the IEA has released its report online entitled Water for Energy: Is energy becoming a thirstier resource?, detailing how much water is used by various energy processes and assesses the sector’s vulnerabilities as rising population and growing economies constrain water resources around the globe.
According to IEA figures, global water withdrawals for energy production in 2010 were estimated at 583bn cubic metres (bcm), or some 15pc of the world’s total water withdrawals.
Of that, water consumption – the volume withdrawn but not returned to its source – was 66 bcm.
In its new policies model, the IEA expect withdrawals to increase by about 20pc between 2010 and 2035, but consumption will rise by 85pc.
While clean tech is a far more water-efficient energy-producing technology in comparison with the established oil and gas energy production, some elements of clean tech are some of the least water-efficient energies.
Hydropower producers, specifically those that also feature a large reservoir, are considered one of the worst offenders, as the water that is ejected after use by the turbines has been slightly altered in aspects such as temperature, flow times and disturbance of water ecosystems.
Likewise, nuclear power is the least efficient by a considerable margin, given the polluted water output that is pumped through the reactor for cooling along with solids left in the water after processing, known as ‘boiler blowdown’.
Fossil fuels remain the biggest users, however, as water withdrawals per unit of electricity generated are highest for coal, gas and oil-fired plants operating on a steam-cycle, as well as nuclear power plants with the once-through cooling process, consuming between 75,000-450,000 litres per megawatt-hour.
Speaking about the report, the IEA’s executive director, Maria van der Hoeven said: “Since water and energy are essential resources, we need to find ways to ensure that use of one does not limit access to the other. As demand for both continues to increase, this will be a growing challenge and priority.”