As Texas stares down a water shortfall, its leaders are looking at vast volumes of brown, briney oilfield wastewater as a hopeful source of future supply. They don’t have many other options.
But extracting clean water from this toxic slurry will require enormous amounts of energy, just as Texas fights to keep up with the rapidly growing power demands of a high-tech industrial buildout.
At current efficiency levels, treating all the effluent of the West Texas oilfield would require up to 26 gigawatts of power, more than the total generation capacity of most U.S. states. Even if operators achieved their ambitious target efficiencies, the Permian would still need an additional five gigawatts, enough to power about five million average American homes.
“It’s just more power needed when we’re already stressed,” said Doug Robison, a longtime fracking executive whose new company, Natura Resources, plans to use small nuclear reactors to treat the wastewater. “We need to add water back into the state’s supply.”
Leaders in Texas are scrambling to head off water shortages predicted by the year 2030 with few new water sources to tap. Meanwhile, wastewater volumes in Texas’ Permian Basin, the nation’s most productive oilfield, have increased sharply in recent years to a staggering 25 million barrels, or about a billion gallons, per day, according to findings that a state-funded research group, the Texas Produced Water Consortium, will present to lawmakers later this month.
“It’s a lot of water,” said Shane Walker, director of the Consortium at Texas Tech University. “Instead of just throw it away, we could treat it and recover some.”
In January, the Consortium signed an agreement with Robison’s company, Natura, to develop a wastewater treatment facility powered by the heat of a next-generation molten salt nuclear reactor. Natura is one of two U.S. companies with permits to build such a reactor, and is currently building its first unit at Abilene Christian University—part of Texas’ plan to meet tremendous incoming industrial power demands with widespread deployment of small nuclear reactors.
Meanwhile, lawmakers in Austin are pushing to make billions of dollars of public financing available to projects that can treat oilfield wastewater for reuse in agriculture or industry. Skeptics argue that water purification will probably never amount to more than a marginal solution, given its cost.
Wastewater from the West Texas oilfields, which comes back to the surface after hydraulic fracturing, or fracking, is practically the filthiest fluid to ever be contemplated for treatment. It’s up to seven times as salty as the sea, full of proprietary drilling chemicals and naturally occurring hydrocarbons, ammonia and radioactive elements from the earth. It can’t be treated by the most common methods that use membrane filters, so companies are racing to apply other heat-based processes.
“Typically, thermal desalination requires more energy,” Walker said. “We’re going to need more energy.”
That’s where Natura’s nuclear reactor design comes in. The unit wouldn’t supply electricity, just raw heat to slowly evaporate clean water from the brine, which is easy since a molten salt reactor runs at over 1,000 degrees Fahrenheit, far hotter than traditional nuclear reactors.
Thermal processes for desalination aren’t new, but they are mostly applied to smaller-scale treatment within industrial operations because of their large energy requirements.
In the Permian Basin, however, the volumes in question are enormous. Oil wells can spit up three barrels of wastewater for every barrel of crude, about a billion gallons every day. That’s enough to cover a square mile in five feet of brine. Almost all of that brine is pumped back underground at high pressure for disposal, which continues to cause intensifying earthquakes, surface blowouts and other environmental disasters across the area.
Injection will continue for the foreseeable future. Large scale solutions for water treatment remain years away and will require a massive buildout of energy supply that will likely include many new gas plants and wind and solar facilities before a new nuclear reactor is deployed.
Current water treatment pilot projects in the Permian Basin are targeting energy costs between five and 25 kilowatt hours per barrel of wastewater treated.
That compares with 1.3 kilowatt hours per barrel to desalinate seawater and 0.3 kilowatt hours per barrel to treat municipal wastewater, according to Mike Hightower, director of the New Mexico Produced Water Research Consortium, who has published research on the energy costs of water treatment.
For 1.05 billion gallons of effluent daily from the Texas side of the Permian Basin, that comes out between five and 26 gigawatts of power demand, approximately the statewide generation capacities of Idaho and Indiana, respectively.
“It’s expensive from an energy perspective; you need a lot of energy to treat this water,” Hightower said. “People need to think about costs and benefits rather than just cost.”
When Texas lawmakers devised a plan in 2023 to expand the state’s water supply, they found most sources were totally tapped out. The lakes were fully allocated, the rivers all spoken for and the aquifers all over-pumped. They identified just three new potential sources of water: desalinated seawater, deep, salty groundwater and treated oilfield wastewater.
Hightower estimated Texas could grow its GDP by $10 billion if it unlocked this new water supply for industrial projects, data centers or farms in its arid west.
At the same time, he said, it could protect oil companies from possible limits on production due to the environmental effects of wastewater injection. In recent years, Texas authorities have begun limiting injections in certain areas due to strengthening earthquakes and geysers of gassy brine. As the problems only get worse, future restrictions on wastewater disposal could ultimately limit oil production.
“Treatment is more expensive than disposal, but it’s essentially a risk management strategy. It buys you insurance that you’re not going to have to cut production if there’s more seismicity,” Hightower said. “You can continue your operations because you are reducing your disposal needs.”
Christine Guerrero, a career petroleum engineer in Houston, said companies won’t opt to treat their wastewater until the costs are lower than injection disposal.
“It’s simply too expensive,” said Guerrero, an independent advisor who previously worked for Schlumberger, Chevron and Hess Corporation. “Unfortunately there’s too many companies in the industry that are not going to do the right thing until they’re forced to.”
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This story was originally published by Inside Climate News.
