Lithium: How sustainable is 'white gold?'
March 13, 2023
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 in 12 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.
1. 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 two years. The concentrated brine is then filtered and lithium carbonate, a basic material for battery production, is chemically extracted. Carbon dioxide 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.
2. 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.
According to a US study, the process of extracting lithium from ores also uses about twice as much fresh water as that of removing it from salt lakes. Greenbushes large open-pit mine is located in a very humid region of southwestern Australia.A sustainability report by the Federal Institute for Geosciences and Natural Resources found water consumption is therefore less problematic in that instance. In the dry Pilbara mining region in northern Australia, however, water supply is a greater challenge.
3. Lithium from geothermal energy
Lithium prices are very high, and in order to meet the rapidly increasing demand for car batteries, several initiatives are now also being promoted in Europe. This includes mining projects in Finland, Ireland, Germany, the Czech Republic, Austria, Serbia, Spain and Portugal.
Similar to the system in Australia, lithium is to be extracted from solid rock deposits in open-pit and underground mines. The projects are all considered profitable.
Separately, projects for lithium extraction from thermal water are being developed in the UK, France and Germany. Geothermal plants pump water from depths as low as 5,000 meters (16,404 feet) at temperatures of up to 200 degrees Celsius (392 degrees Fahrenheit) and use the heat to generate electricity and for heating networks. The cooled water is then forced back underground.
In some cases, the extracted water contains lithium, which can be directly separated by advanced lithium extraction (DLE) technology. To date, such extraction plants do not exist on a large industrial scale.
The German-Australian company Vulcan Energy plans to start commercial extraction in the Upper Rhine Valley in southern Germany, producing 4,000 tons of lithium in the first phase in 2025. Some three million tons of the light metal are believed to exist in Vulcan's mining area.
The lower environmental impact is cited as an advantage of this process: The energy for the extraction process comes from deep geothermal energy, so it is climate-neutral, and in addition, this lithium no longer has to be transported across oceans for European battery production.
4. Saving lithium through recycling and sales
In a few decades, lithium could also be extracted as a by-product at desalination plants, and fill supply gaps. At present, this extraction method is not deemed profitable.
In the future, lithium extraction from old batteries will also become important. According to DERA scenarios, recycling will cover part of the lithium demand in the 2030s.
Currently, however, the available battery volumes are too small for commercial extraction, and lithium batteries from e-cars are installed in large battery storage systems, for example in solar parks.
"Once the volumes of used batteries increases, however, we will see more lithium from recycling. This is also imperative in terms of sustainable use," said Michael Schmidt.
In addition, raw materials experts like Schmidt and environmental associations are calling for the most efficient use of lithium and batteries. They say that building large e-cars with the largest possible batteries is not a sustainable use of resources.
Instead, lighter vehicles with batteries should be sold as a priority and made available for as wide a consumer base as possible. It would also be helpful to expand car-sharing services and public transport so that fewer people would need their own e-car, allowing a reduced demand for the so-called white gold.
This article was originally published in German.