A new study finds that increasing water scarcity could hinder the expansion of lithium mining in the US, deepening its dependence on foreign imports in the coming decades.
Lithium Because of its high energy density and low weight compared to other minerals, it is used in electric-vehicle and energy-storage batteries, but mining it requires huge amounts of water. Currently, only the US has An active lithium mine in NevadaAccording to the study, and with demand for the metal projected to increase over the next few years, the government and private companies are planning to open at least 115 new mines across the country.
However, most of the proposed mines that are in advanced stages of development overlap with water-stressed areas, particularly in the western US, the new study, published May 28 in the journal Nature, found. communication earth and environmentScientists found that if lithium mines were to operate in these areas, they would compete for water not only with households, agriculture and industry, but also with each other and with other proposed mineral mines.
“Future water availability under climate change may dictate whether new lithium mines will have enough water to operate,” the study’s senior author says. Jennifer Dunnprofessor of chemical and biological engineering and director of the Center for Engineering Sustainability and Resilience at Northwestern University in Illinois, told Live Science in an email.
US imports more than 50% of its lithiumMostly from Chile and Argentina. Dunn said policymakers and corporations want to reduce this dependence, but even with the existing Nevada mine and the 22 proposed mines that are closest to coming online, the U.S. will not have enough lithium to meet domestic demand.
“Each mine produces a different amount of lithium – depending on its deposit type, lithium grade and final product – so we are unable to determine exactly how many mines will need,” he said. “Our analysis estimates that if all 22 advanced [stage] Proposed mines and the only operated mine to remain operational till 2050, 0.14 [to] 0.25 million metric tons [0.15 to 0.28 million tons] The lithium content in the products can be produced per year.”
This range is less than the 0.83 million to 1.9 million tonnes (0.75 million to 1.7 million metric tons) of lithium per year previously estimated by other researchers. estimated America will need to meet its demand.
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However, the demand for water to produce more lithium would be too high. This is because lithium is usually extracted from salt water. Rocks known as pegmatitesWhich requires large scale evaporation and aggressive processing with fresh water respectively.
To determine whether the US will have enough water to support additional lithium mines under intensification Climate changeThe researchers calculated the future water use of 23 lithium mines expected to be active in 2050 using data from mining companies. Then, they layered this projected water use on top of projected water use from other sectors, such as agriculture and manufacturing, under four modeled socio-economic-climate scenarios between 2040 and 2060.
The researchers found that the available water supply would, in most cases, be insufficient to support new lithium mines. The clearest example of this was the Salton Sea off southern California, which contains about 4.5 million tonnes (4.1 million metric tons) of lithium. The Salton Sea is fed by the Colorado River and has the least amount of water available to meet lithium mining and other water demands, Due to decreasing flow of the river.
Southern California’s Salton Sea has been shrinking for decades, partly because the flow of the Colorado River has decreased. The geothermal brine reserves beneath the seafloor are believed to be one of the planet’s largest reserves of lithium.
(Image credit: Mario Tama via Getty Images)
Lithium reserves in America are deposited in Nevada, Arizona and California. these are also Some of the most arid and water stressed states. Although the study found increased precipitation under a high-emissions, “business as usual” climate scenario, these areas would not have enough water to support other activities, let alone additional lithium mining, Dunn said.
There were four exceptions in the study, including lithium-rich sites in North Carolina and Arkansas that may have enough water to support future mines. However, there are other concerns related to lithium mining.
“Many of the lithium deposits in the United States are near federally recognized indigenous and tribal reservations, and mines may violate indigenous rights,” Dunn said. “Lithium mining can also disturb sensitive ecosystems and biodiversity. And, Like many other mineral minesPollution, soil erosion and water pollution are areas of concern.”
Together, the findings highlight a Catch-22 in the search for a lithium source: Lithium is essential to support the green energy transition and curb climate change, but reduced water availability due to global warming is making it harder to extract lithium.
The study did not explore potential improvements in water-use efficiency that could reduce pressure on some water resources and increase availability for activities such as lithium mining. Due to a lack of studies about these transfers under climate change, neither researchers included water exchange, known as interbasin transfer (IBT), in their analysis.
“IBT can help supply water to arid or water-scarce areas,” Dunn said.
Still, according to the study, there is likely an upper limit to how much water can be allocated for lithium mining in a warming world. This means the US will likely continue to be partially dependent on foreign supply chains for lithium and other critical minerals.
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