The development of new renewable energy technologies and other expanding sources of energy such as shale gas will be limited by the availability of water in some regions of the world, according to research by a US thinktank.
The study shows the reliance on large amounts of water to create biofuels and run solar thermal energy and hydraulic fracturing – a technique for extracting gas from unconventional geological formations underground – means droughts could hamper their deployment.
"Water consumption is going up dramatically. We are introducing all kinds of technology to reduce the carbon impact of energy, without doing anything to reduce its impact on water," Michele Wucker, co-author of the report, told a seminar at the New America Foundation, a thinktank in Washington.
The study, estimating the water consumption of conventional and renewable energy, found even so-called clean energy solutions use vast amounts of water.
Hydroelectricity far outstrips other forms of energy in its use of water, requiring 4,500 gallons to produce a single megawatt hour of electricity – or about the amount needed to run a flat-screen TV for a year. Geothermal energy uses 1,400 gallons per MW/h.
Corn-based ethanol uses a lot of water to irrigate crops, as do nuclear plants which rely on water for cooling systems. Even some renewable energy sources – such as solar farms – are water hogs because they rely on water for cooling.
Solar thermal farms use five times as much water as nuclear power plants, energy consultant Diana Glassman told the seminar. In contrast, photovoltaic solar cells, which convert energy from the sun into electricity, use minimal amounts of water.
Meanwhile, the US drought is forcing energy companies to scale back plans for deploying new techniques in hydraulic fracturing ("fracking") for oil and gas extraction. Not long ago, energy companies were hoping to increase production in Texas by 50% over the next five years.
Unlike in Pennsylvania, where the chemicals used in natural gas drilling have contaminated drinking supplies, the problems in Texas are a matter of water quantity, not water quality.
"The drought and declining water tables are going to have an increasing impact on oil and gas production in Texas," Glassman said.
It takes up to 13m gallons of water to open up a single well in the Eagle Ford shale region in south Texas, where water is in perennially short supply. Such demands are going to block development of areas in south and west Texas, which are suffering water shortages.
"As hydraulic fracking spreads into more arid environments, water availability will increasingly become a problem. Over time it's going to be a growth constraint on oil production in parts of West Texas," said Glassman.