In the quest for greater mileage per charge, electric car batteries are getting much bigger. But since battery production is energy consuming and to some extent cancels out climate benefit, it is vital that production becomes more energy efficient and that the use of fossil electricity is minimized. This according to a report that IVL Swedish Environmental Research Institute has carried out on behalf of the Swedish Energy Agency and the Swedish Transport Administration.
– Electric and hybrid cars have major advantages over petrol and diesel vehicles, especially when it comes to local emissions and noise levels. But it is also important to assess the whole picture and to minimize environmental impact in the production stage, says Lisbeth Dahllöf, researcher at IVL Swedish Environmental Research Institute.
Together with colleague Mia Romare, she has reviewed the literature on greenhouse gas emissions and energy consumption during the production and recycling of lithium-ion automotive batteries for light vehicles.
According to the authors of the report, the production of lithium-ion batteries for light electric vehicles releases on average 150-200 kilos of carbon dioxide equivalents per kilowatt-hour battery. One of the smallest electric cars on the market, Nissan Leaf, uses batteries of approx. 30 kWh; many new models have batteries of 60 and 100 kWh. An electric car with a 100kWh battery has thus emitted 15-20 tons of carbon dioxide even before the vehicle ignition is turned on. This calculation assumes a 50-70 per cent fossil share in the electricity mix.
– This means that you shouldn’t buy an electric car with a larger battery than is necessary. For a sustainable future, it is important that the production of electric car batteries is as energy-efficient as possible and made with electricity that is either completely without, or with a very low, carbon emission, says Mia Romare.
However, the authors of the report emphasize that this very technology is developing rapidly and that their figures address today’s situation, and that there is a need for more data from the manufacturers. Figures also vary according to battery design.
Automotive batteries contain metals such as lithium and often cobalt and nickel. Since metal extraction is chemically intensive, finite and energy demanding, it is important to make significant advances in this area. The study also points to the need to supplement the carbon labelling of vehicles in use today with information about manufacturing and end-of-life treatment.
– A first step should be to require vehicle manufacturers to produce so-called environmental product declarations for electric vehicles, and to include life cycle analysis data from the manufacturing process, says Mats-Ola Larsson, who works with mobility and policy instruments at IVL.
– Future policy instruments should take emissions into account during the manufacturing phase as well. For example, electric cars with large batteries should not be favoured over those with smaller ones. Car manufacturers should also place higher demands on battery suppliers. This report shows the importance of continuing to investigate the best way forward, he says.