In 2007, a geoscientist at Penn State named Terry Engelder calculated that Pennsylvania could be sitting on more than 50 trillion cubic feet of accessible natural gas deposits. Engelder later revised his calculation upward, to 489 trillion cubic feet, enough to meet U.S. natural gas demand for 18 years. These massive numbers set off the fracking boom in Pennsylvania, leading to drilling across the state. Since the rush began, there have been 13,000 unconventional wells drilled in Pennsylvania.

Now, a new “astounding” calculation has caught the attention of the gas industry: A study from researchers at the National Energy Technology Laboratory shows the wastewater produced by Pennsylvania’s unconventional wells could contain enough lithium to meet 38 to 40 percent of current domestic consumption. Lithium is a critical mineral that’s an “essential component” of many clean energy technologies, including batteries for electric vehicles. 

The study used chemical and production compliance data from the Pennsylvania Department of Environmental Protection to estimate that approximately 1,160 metric tons of lithium per year could be extracted from this produced water, which is a combination of fluids used for fracking and water from natural formations underground that returns to the surface during the drilling process. The lithium in Pennsylvania’s produced water likely comes from ancient volcanoes that were erupting at the time the natural gas deposits were being formed. This volcanic ash contained lithium that eventually seeped into the water underground.

“The researcher community in the U.S. is really working hard to find the materials and methods that will enable us to meet our climate goals and decarbonize the economy,” said Justin Mackey, the study’s lead investigator. “Sometimes you might be surprised where that material actually comes from.” 

The Marcellus Shale Coalition, an industry trade group dedicated to the Marcellus Shale formation, the natural gas deposit beneath Pennsylvania, West Virginia, Ohio and New York, reacted to the news with enthusiasm. “This scientific analysis by one of the leading energy laboratories in the world shows once again how abundant Pennsylvania natural gas can enhance America’s energy, environmental and national security,” the coalition said in a statement. 

The United States currently relies on imports from Argentina, Chile and China to fully meet its lithium needs, and the demand for lithium is expected to rise dramatically as the clean energy transition accelerates. 

Mackey, a research geochemist at the National Energy Technology Laboratory, said he had focused on lithium because it is a strategic material for the American economy and defense industries and because it has insecure supply chains. “We’re reliant on foreign entities like China and Chile and Australia to source these raw materials, but they’re critical to our economies,” he said. “And more importantly, they’re critical to decarbonizing the U.S. automotive fleet.”

He said the researchers were “shocked” that the highest concentrations of lithium found in the Marcellus “are comparable to lithium brine, to water that is actually being mined for lithium.” 

“I think having more domestic sources of lithium is definitely a positive thing, especially if you don’t have to create a mine to exploit the resource,” Mackey said. Unconventional drilling waste is likely to be produced in large quantities for the foreseeable future, he said, and if remediating this waste safely could also be made economically valuable, that could be beneficial for the environment as well.

But other experts are skeptical about the potential benefits of the study’s findings, questioning the economic feasibility of extracting lithium from wastewater at scale and what kind of impacts this processing could have on the environment and public health.

“There’s a lot of unanswered questions. It’s a little early, I think, to get too excited. It’s certainly something that needs to be looked at,” if only because of America’s reliance on lithium imports, said John Quigley, a fellow at the Kleinman Center for Energy Policy and a former secretary of the Pennsylvania DEP and the state’s Department of Conservation and Natural Resources. 

The costs of extracting lithium in this way are unknown, Quigley said, and that includes the costs of surmounting potential logistical challenges of processing and transporting wastewater that comes from well pads across hundreds of miles of land. 

So far there is one Pennsylvania company, Eureka Resources in Lycoming County, working on lithium extraction from produced water. In 2023, the company announced it had successfully extracted “97 percent pure lithium carbonate” from wastewater and plans to incorporate the process at its three Pennsylvania facilities within the next two years. 

Even if the process of extracting lithium proved to be cost-effective, Quigley said, it should not be used as a justification to keep drilling, though it was “inevitable” that the industry would try to use the finding that way. “It’s still not a reason to continue to drill, because it’s a waste product from fossil fuel extraction,” he said. “The economy has to be carbon free by 2050.” 

Extracting lithium doesn’t solve the ongoing problem of what to do with the highly toxic wastewater produced by fracking, which contains salts, metals and radioactive elements. “There’s no way to clean this stuff up,” Quigley said. “You might be able to get something beneficial out of it. But you still have really nasty wastewater that you’ve got to get rid of.”

Quigley was reminded of previous claims made about the economic usefulness of the oil and gas industry’s wastewater in Pennsylvania. Spreading wastewater from conventional drilling on roadways to suppress dust was once considered “a beneficial reuse,” but now faces scrutiny for the risks it poses to the environment and human health, including water contamination and harm to aquatic wildlife. “That has proven to be a sham,” Quigley said. “Some beneficial reuses turned out not to be so beneficial.”

“You might be able to get something beneficial out of it. But you still have really nasty wastewater that you’ve got to get rid of.”

Shannon Smith, the executive director of FracTracker, a nonprofit based in Pennsylvania that analyzes the impacts of oil and gas development, wondered how the industry might use this finding to expand their operations in the state. 

“I live in Pennsylvania, and we’ve been burned over and over and over by the industry,” Smith said. “Being so deeply embedded in this world, I know that when something sounds too good to be true, it is too good to be true.”

“On the one hand, it seems like common sense. If they’re producing this dangerous waste, they should be obligated to at least make use of it how they can,” she said. But she worried if the U.S. became dependent on the Marcellus for 40 percent of its lithium supply, it would perpetuate fracking in Pennsylvania. Real climate solutions need to include a pathway to transition completely away from fossil fuels, she said. 

Smith also questioned whether Pennsylvania’s regulators were up to the task of monitoring another extractive industry. “The most common sense interventions are not being taken to protect our health,” she said. “So why on earth would we trust them to manage a new lithium economy?”

Because water production from typical wells in the Marcellus declines by 80 percent within the first two years of operation, the study concluded that extracting the volumes of lithium described in this analysis “would require continuous addition of new Marcellus wells to supplant older, less productive wells.” The study pointed to “underdeveloped” north-central Pennsylvania as a place where some of those new wells could be drilled; this region “has some of the highest lithium concentrations included in our analysis.”

Mackey and one of his co-authors, Barbara Kutchko, said the finding was only a beginning step toward understanding how to help the country meet its lithium needs, and the costs and benefits as well as economic and technological considerations of extracting lithium from produced water still need to be studied in greater depth. 

Quigley was cautious about speculating on what this finding could mean for Pennsylvania’s future. “I’ve seen too many stampedes that have ended up causing environmental and public health damage as well as economic losses,” he said. “People need to take a deep breath. It’s an intriguing finding. It needs a lot more work before it’s real.” Quigley said other clean energy technologies that do not rely on lithium are being developed, and while lithium ion batteries are seen as “state of the art” now, that may not be the case forever. 

As Pennsylvania looks ahead, he worries that the lessons of the past have not been learned. The history of energy extraction in Pennsylvania is marked by long-term, unintended consequences triggered by the rapid adoption of new technologies, from the lingering aftereffects of coal mining in the 19th and 20th centuries to more recent harm caused by fracking in the 21st. 

“A stampede toward lithium at all costs is not a smart move for the country,” he said. “And certainly not for Pennsylvania.”