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martyb writes:

Replacing Coal with Gas or Renewables Saves Billions of Gallons of Water:

"While most attention has been focused on the climate and air quality benefits of switching from coal, this new study shows that the transition to natural gas—and even more so, to renewable energy sources—has resulted in saving billions of gallons of water," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

[...] "For every megawatt of electricity produced using natural gas instead of coal, the amount of water withdrawn from local rivers and groundwater is reduced by 10,500 gallons, the equivalent of a 100-day water supply for a typical American household," said Andrew Kondash, a postdoctoral researcher at Duke, who led the study as part of his doctoral dissertation under Vengosh.

[...] If all coal-fired power plants are converted to natural gas, the annual water savings will reach 12,250 billion gallons—that's 260% of current annual U.S. industrial water use.

Although the magnitude of water use for coal mining and fracking is similar, cooling systems in natural gas power plants use much less water in general than those in coal plants. That can quickly add up to substantial savings, since 40% of all water use in the United States currently goes to cooling thermoelectric plants, Vengosh noted.

[...] Even further savings could be realized by switching to solar or wind energy. The new study shows that the water intensity of these renewable energy sources, as measured by water use per kilowatt of electricity, is only 1% to 2% of coal or natural gas's water intensity.

"Switching to solar or wind energy would eliminate much of the water withdrawals and water consumption for electricity generation in the U.S.," Vengosh said.

Quantification of the water-use reduction associated with the transition from coal to natural gas in the U.S. electricity sector, Environmental Research Letters (DOI: 10.1088/1748-9326/ab4d71)

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