When it comes to hydrofracking, it’s the fracturing that gets a lot of the attention, but in fact it’s the hydro part of that is particularly troublesome. Even if fears over the contamination of groundwater supplies with toxic frac water can be overblown, environmentalists argue that hydrofracking simply uses too much water—especially in arid drilling regions like Texas. Between 4 and 6 million gallons (15 to 23 million liters) of water is used every time a gas or oil well is fracked, and with the energy boom booming, that can add up to a lot of water, as Hillary Hylton noted in a piece for TIME earlier this year.
But a new study argues that fracking for natural gas actually seems to save water in the aggregate, by making it easier for utilities to switch from thirsty coal plants to more efficient natural gas power. Researchers from the University of Texas at Austin collected water use data from all 423 of the state’s power plants. They estimate that the water saved by switching from coal to natural gas is 25 to 50 times greater than the amount of water used in fracking to extract the shale gas in the first place. In 2011, the researchers estimate that Texas would have consumed an extra 32 billion gallons of water if all its natural gas-fired power plants were instead burning coal. “The bottom line is that hydraulic fracturing, by boosting natural gas production and moving the state from water-intensive coal technologies, makes our electric power system more drought resilient,” said Bridget Scanlon, senior research scientist at the University of Texas’s Bureau of Economic Geology and the lead author on the study.
The study is a reminder that for all the focus on the water consumed in fracking or by farms through irrigation, one of the single biggest users of water is the power industry itself. Thermoelectric generation—that would be technologies like coal, natural gas and nuclear, which use heat to generate steam—account for approximately 40% of the freshwater withdrawals in the U.S. In arid regions and during droughts—like the historic 2012 drought, which at its height covered up to 65% of the U.S.—water can become so scare that power plants may need to reduce operations or shut down altogether. With population increasing—especially in fecund and popular Texas—and demand rising, the so-called “water-energy nexus” will be a growing challenge for decades to come.
But the huge amount of water used by power plants tends not to get the kind of attention that fracking does—probably because fracking, especially on a large scale, is relatively new, while coal and natural gas plants have been around for decades. (The Texas State Water Board estimates that hydrofracking accounts for less than 1% of total water use, while providing more than 10% of the state’s total economic output.) Fracking for oil and gas is also much more distributed than a centralized power plant is; if you live in Texas, chances are much better that you live closer to a fracked well than you do a power plant. Power plants—and the mining of the coal used in many of them—are out of sight, and thus they’re out of mind.
Still, the fact remains that Texas was a water-stressed state well before the first gas well was fracked, and the concentration of fracking in certain areas of the state can strain local water supplies. Water use for fracking in Texas is also growing rapidly, from 36,000 acre-feet in 2008 to 81,500 acre-feet in 2011. That’s why oil and gas drillers will need to start recycling frac water, or find substitutes that don’t need water at all, like the liquid petroleum gel made by the Canadian company GasFrac. Water is scarce now in Texas and its likely to be even scarcer in a hotter and more crowded future. Every industry—including oil and gas—will need to figure out a way to use our most precious resource more efficiently.