How sustainable is lithium, the white gold?

An electric car doesn’t actually need very much lithium to run. A 300-kilogram battery (50 kWh) of a mid-sized model only contains around eight kilograms of the light metal. Even so, as the electric vehicle sector gathers greater speed than many expected, demand for the element, which is needed for making batteries, is increasing. Given that lithium extraction projects take several years to develop and can be controversial, that is problematic. Some projects have met with protests because open-pit mines destroy landscapes and water supplies can be affected. In 2016, 43,000 metric tons of lithium were mined worldwide, according to the German Mineral Resources Agency (DERA). By 2022, that figure was three times higher at 130,000 metric tons, and by 2030, the body says, the amount mined could more than quadruple again.

DERA lithium expert Michael Schmidt says the question is now how to sustainably extract enough battery-grade lithium to meet demands. “There are dynamics at play that I’d not previously witnessed in12 years of resource management.” Lithium, often referred to as “white gold” due to its market value and silver color, is actually abundant in the earth’s crust, but is very finely distributed. Researchers estimate the amount of the light metal in the world’s oceans at around 200 billion tons. Deposits in rocks and salt lakes on land are believed to add up to 98 million metric tons, 26 million of which would be economically mineable in the coming decades. In 2022, 47% of global lithium demand was met by mining solid rock in Australia’s open-pit mines, 35% from South America’s salt lakes, 15% from China, and just under 1% each from Zimbabwe, Portugal, and North America.

Lithium from salt lakes

The world’s largest lithium deposits are found in the underground salt lakes of Bolivia, Argentina and Chile, which are estimated to hold 42 million tons of the metal. According to preliminary figures from the US Geological Survey, about 45,000 tons were mined there in 2022.

The salty brine is pumped from the depths into huge basins where it evaporates in the sun within up to two years. The concentrated brine is then filtered and lithium carbonate, a basic material for battery production, is chemically extracted. CO2 emissions from this extraction method are relatively low, ranging from 50 to 100 kg of CO2 for a car battery (50 kWh), according to a study by the Swedish Environmental Research Institute.

However, this type of lithium extraction can lead to problems in drinking water. Pumping out brine can lower groundwater levels, while river courses and wetlands can dry up. In some regions there is a lack of water for agriculture.

Lithium from solid rock

The largest volume of lithium is currently extracted by mining solid rock (pegmatites) in open pits in Australia. According to preliminary estimates, about 61,000 tons were extracted there in 2022. Australia’s lithium reserves are currently thought to total 6.2 million tons.

Lithium ore is mined by drilling and blasting. The lumps are then crushed in a plant, and the lithium is separated from the overburden by chemical and metallurgical processes. Next, the lithium goes to China by ship, where it is refined and processed into battery cells. According to a study by Argonnen National Laboratory — a US federally funded research and development center — lithium extraction from ores is about six times more energy-intensive than from salt lakes, and therefore more harmful to the climate.