A recent study published in Nature's Scientific Reports titled "Estimates of lithium mass yields from produced water sourced from the Devonian-aged Marcellus Shale" suggests that wastewater from Pennsylvania's Marcellus Shale, a rock formation found throughout the northern Appalachian Basin, could be a significant domestic source of lithium, potentially meeting up to 40% of the U.S. demand. 

Using data from the Pennsylvania Department of Environmental Protection and Monte Carlo simulation methods, the study estimates that the Marcellus Shale could yield approximately 1160 metric tons of lithium annually. However, the extraction potential varies between Pennsylvania's northeast and southwest regions due to differences in production volumes and lithium concentrations in the produced water (PW).

Statewide, the Marcellus Shale PW is projected to yield about 1160 metric tons of lithium per year, with individual wells in the southwest region producing more lithium (2.90 metric tons over ten years) compared to those in the northeast (1.96 metric tons over ten years). The southwest region's PW has higher magnesium-to-lithium (Mg/Li) mass ratios, making extraction more challenging and costly than the northeast, which has lower Mg/Li ratios favorable for more economical extraction methods. The Marcellus Shale's unique geological history, including Middle Devonian volcanism, has enriched its PW with lithium, making it a suitable target for extraction.

The study also highlights the current practice of recycling 95% of PW in ongoing fracking operations, which must be balanced with lithium extraction efforts. The environmental impact of extracting lithium from PW, such as increased transportation and waste management, must be considered in developing this new resource. 

The U.S. Geological Survey lists lithium as a critical element, and the Infrastructure Investment and Jobs Act mandates that raw materials for electric vehicle batteries be sourced domestically by 2030. The study's findings suggest that Marcellus Shale PW could play a crucial role in meeting these requirements, providing a substantial domestic lithium source that could reduce reliance on international supply chains.

To capitalize on this potential, further research is needed to optimize extraction techniques and understand the environmental implications. Establishing pilot facilities for lithium extraction from PW is critical to achieving large-scale production. This study underscores the importance of innovative approaches to resource management, turning wastewater from oil and gas operations into a valuable asset for the U.S. energy transition.

Read more by visiting Nature's Scientific Reports.

Related stories:

In Rush for Lithium, Miners Turn to the Oil Fields of Arkansas, Yale Environment 360, February 29, 2024

How to make lithium extraction cleaner, faster and cheaper — in six steps, Nature, April 6, 2023