Could Pennsylvania’s fracking wastewater hold the key to the country’s energy transition?

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About seven years ago, Justin Mackey was working as a consultant for the gas industry in Pennsylvania, sampling the salty water that flows up from the Marcellus Shale formation while drilling and fracking for natural gas.

While fracking injects water into the wells to release the gas, it’s a fraction of the amount of water that returns back up the well. Water embedded within the formation for hundreds of thousands of years is extremely salty and contains toxins like benzene or toluene, as well as heavy metals and radioactive materials. When it rises up to the surface, it is referred to by the oil and gas industry as “produced water.”

“In the U.S. we’re producing about 2.8 billion liters a day of produced water,” Mackey said.

Much of that water is re-injected back into the well to produce more gas. But a lot of it has to get trucked to Ohio and disposed of through a deep injection well, an expensive undertaking.  Each well in Pennsylvania is required to report to the state the chemical composition of that wastewater.

Mackey, who is now a PhD student at the University of Pittsburgh and works at the Department of Energy’s National Energy Technology Lab, wondered what the state did with all that data. Using the state’s Right-to-Know law, he was able to analyze the contents of 630 samples. He discovered that the waste product of natural gas production in Pennsylvania could help with the transition from the fossil fuel–powered combustion engines to electric vehicles because it contains a large concentration of an essential ingredient for batteries: lithium.

“We found … that the produced water from the Marcellus has comparable amounts of lithium to the brine ponds in Chile, which is the global, dominant source of lithium in the world,” Mackey said. “And more importantly, it has comparable lithium concentrations to the Arkansas Smackover [formation] and other formations that are actively being targeted for brine mining in the U.S.”

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.

Mackey said it wouldn’t be ideal, or even economically feasible, to start drilling specifically for lithium in the Marcellus Shale. But he said if the wastewater is already a product that has to be treated and disposed of, it makes sense to extract the lithium.

“If we can start having value-added materials and remediate this waste such that it’s not an environmental issue, I think that’s my preferred outcome,” Mackey said.