This isn’t another tired story about how kicking the coal habit will reduce greenhouse gas emissions. That would be like kicking a dead horse.
Instead, there is a massive new benefit to ditching the dirty: Doing so will free up billions of gallons of water.
If all coal-fired power plants in the U.S. were converted to natural gas, the annual water savings could reach 12,250 billion gallons, or 260 percent of current annual U.S. industrial water use, according to a new study from Duke University.
Arguably, ditching coal could make up for all the water that fracking is sucking down in the shale patch, so it could take the pressure off that controversial method of extracting oil.
At the same time, coal can largely blame its own demise on this hydraulic fracking boom that has led to abundant natural gas supplies.
Natural gas has surpassed coal as the top power generation source as of 2015.
In 2018, natural gas accounted for 35.1 percent of the U.S. electricity generation mix, while coal had a 27.4 percent share.
Renewables, especially wind and utility-scale solar, have also gained traction in recent years, grabbing additional share from coal in U.S. electricity generation.
If these trends hold until 2030, the U.S. would save some 483 billion cubic meters of water each year by 2030, which may help take some of the heat off of fracking, where water use has soared over the past decade.
Another Duke University study from last year showed that the amount of water used per well surged by up to 770 percent between 2011 and 2016 in all major U.S. shale gas and oil production regions.
But fracking isn’t the biggest bogeyman when it comes to water waste.
Despite the fact that the amounts of water used in coal mining and fracking are similar, coal-fired plants use much more water to cool than natural gas-fired plants, according to Duke.
“The amount of water used for cooling thermoelectric plants eclipses all its other uses in the electricity sector, including for coal mining, coal washing, ore and gas transportation, drilling and fracking,” said Avner Vengosh, professor of geochemistry and water quality at Duke’s Nicholas School of the Environment.
According to EIA data, water withdrawals by U.S. power plants have been declining in recent years, mostly because the share of coal in U.S. electricity generation fell from 39 percent in 2014 to 30 percent in 2017, while the natural gas share increased from 27 percent to 32 percent.
Electricity generation from wind and solar requires almost no water, while combined-cycle natural gas power plants need less water on average than a coal-fired power plant.
In fact, the best argument for fracking yet is this:
“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.
The rise of wind and solar power generation could lead to even more significant reductions of water use, according to the study. The water intensity of these renewable energy sources—measured by water use per kilowatt of electricity—is only 1 percent to 2 percent of the water intensity of coal or natural gas.
“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,” Vengosh said.
Earlier this year, the EIA estimated that renewables held a larger share than coal in U.S. monthly electricity generation in April 2019, for the first time ever. This historic achievement reflected seasonal factors and longer-term trends such as the decline of coal and the rise of renewables, according to EIA.
If these trends hold, the decline of U.S. coal will be about much more than reducing greenhouse gas emissions: They’ll be the savior of industrial water usage. And the death of coal could end up being the best advertisement that fracking has ever had.
By Tsvetana Paraskova for Oilprice.com
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