Mackey’s research, published recently in Nature Scientific Reports, says the brine water that lies deep within the Marcellus Shale — and comes to the surface during gas production — could provide 38–40% of the current domestic demand for lithium, which is estimated at 3,000 metric tons a year. But that demand is expected to jump to 340,000 metric tons by 2032.

Lithium is now considered one of the most essential components for the energy transition. Rechargeable lithium-ion batteries are light and able to store a lot of energy. They power electric vehicles, computers, iPhones and large battery storage facilities.

“So, we’re going to need a lot of lithium if we’re going to decarbonize all of these things,” Mackey said.

The Bipartisan Infrastructure Law requires electric vehicle batteries to use domestically sourced raw materials by 2030. The law’s aim was to reduce dependency on Chinese sources of lithium and will likely increase the domestic demand. The Biden administration also recently imposed steep tariffs on electric batteries and vehicles coming from China.

More than half of the global supply of lithium is extracted from subsurface brine deposits in Chile and Argentina’s Atacama Desert, then shipped to China to be processed into lithium carbonate or lithium hydroxide, which is then used to make lithium-ion batteries.

David Boutt, a hydrogeologist and professor at the University of Massachusetts, Amherst, who  was not involved in the study, said the analysis done shows the Marcellus Shale could be a large source of lithium.

“These are very high lithium concentrations. And some of them are approaching concentrations of lithium that we see in [South America],” said Boutt, who researches lithium systems in the U.S., Canada and South America. He said in South America, there are concerns about extracting too much water in an arid landscape.

“So having a source of lithium in what is essentially a waste product is a really important step,” he said. “I think how we get [enough supply] is having multiple sources of lithium that have low-carbon and low-water footprints.”

But extracting the lithium from the wastewater is not easy, Boutt said, and would require a large amount of energy.

While the U.S. has very little current domestic supply, it does have the world’s first lithium mine in Nevada. The Silver Peak mine extracts lithium using hard-rock mining, which is energy and water-intensive. The Department of Energy just agreed to a $2.26 billion loan to help jump-start another lithium mine in Thacker Pass, Nevada.

A new domestic source of lithium from brine is the Smackover Formation of Arkansas, operated by Standard Lithium. Exxon Mobil has invested heavily in lithium production in that formation.

But questions remain on the economic feasibility of extracting lithium from Marcellus Shale wastewater.

One company that operates in the Marcellus Shale has already begun developing a process to  extract lithium from the wastewater. Eureka Resources reported back in July that it “extracted 97% pure lithium carbonate from oil and natural gas brine from production activities with up to a 90% recovery rate.”

The company is based in Williamsport and operates two wastewater treatment facilities in Pennsylvania. It says it uses a closed loop system that combines “physical and chemical treatment, concentration and crystallization,” similar to the process it uses to extract and sell salts, such as sodium chloride and calcium chloride. In the press release, it said it expects to be selling lithium within two years.

But Boutt said it’s unlikely that oil and gas companies are going to rush to sell lithium. “There’s a lot of work that goes into making battery-grade lithium,” he said.

And once the lithium is extracted, there is still the issue of disposal of the remaining wastewater that could still contain toxic substances, whether it gets used to frack another well or if it gets shipped off to a deep injection well for disposal.