Enormous hopes are linked to electric cars as the solution to the automotive industry’s climate problems. However, electric car batteries are eco-villains during their manufacturing. Several tons of carbon dioxide (CO2) are generated even before the batteries leave the factory.
IVL The Swedish Environment Institute has, on behalf of the Swedish Transport Administration and the Swedish Energy Agency, investigated the climate impact of lithium-ion batteries from a life-cycle perspective. The batteries for electric cars were included in the study. The two authors—Lisbeth Dahllöf and Mia Romare—have done a meta-study, that is, reviewed and compiled existing studies.
The report shows that battery manufacturing leads to high emissions. For each kilowatt-hour of storage capacity in the battery, emissions of 150 to 200 kilograms of carbon dioxide are generated in the factory. The researchers have not studied the individual car brand batteries, just how they were produced or what electrical mix they used. But to understand the importance of battery size, two standard electric cars on the market, Nissan Leaf and Tesla Model S, have batteries of approximately 30 kWh and 100 kWh respectively.
Even before you buy the car, CO2 emissions equivalent to 5.3 tons and 17.5 tons, respectively, gets produced. The numbers can be difficult to put in context. By way of comparison, a trip for a person returning from Stockholm to New York by air emits more than 600 kilograms of CO2, according to the UN organization ICAO’s calculation model.
Another conclusion of the study is that about half the emissions come from producing the raw materials and the other half from the battery factory. The mining accounts for only a small proportion of between 10-20 percent.
The calculation is based on the assumption that the electricity mix used by the battery factory consists of energy generated by more than 50% fossil fuels. In Sweden, the power production is mainly from fossil fuels, nuclear, and hydropower and why lower emissions had been achieved.
The study also concluded that emissions grow almost linearly with the size of the battery, even if it is pinched by the data in that field. It means that a battery of the Tesla-size contributes more than three times as much emissions as the Nissan Leaf size. It is a result that surprised Mia Romare.
Mats-Ola Larsson at IVL has calculated how long you need to drive a gasoline or diesel car before it released as much CO2 as the battery manufacturing produced. The result was 2.7 years of CO2 emissions for a battery the same size as a Nissan Leaf and 8.2 years for a Tesla-sized battery, based on a series of assumptions.
“It’s great for companies and government to embark on ambitious environmental policies and to buy climate-smart cars. But these results show that one should not think of choosing an electric car with a larger battery than is necessary,” he says, pointing out that manufacturers should also address this in the design of instruments.
Cobalt, nickel, and copper are recycled but not the energy required to manufacture the electrodes, says Mia Romare, pointing out that recycling is a resource-saving point rather than a reduction of CO2 emissions.
Peter Kasche from The Energy Agency highlights the close relationship between the battery size and CO2 emissions are important.
In some way, one must really make sure that you optimize the batteries. You should not drive around with a lot of kilowatt hours unnecessarily.
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