Chalmers study: banning the sale of fossil fuel cars dramatically reduces life cycle GHGs, primarily from tailpipe emissions; risk of carbon leakage in manufacturing
If a ban were introduced on the sale of new gasoline and diesel cars, and they were replaced by electric cars, the result would be a significant reduction in life cycle carbon dioxide emissions, mainly due to the reduction in exhaust CO2 emissions, according to a new life cycle study by researchers at Chalmers University of Technology, Sweden.
However, the full effect of a ban is delayed due to fleet inertia. In addition, the risks of carbon leakage over the vehicle’s entire lifecycle may need to be addressed by extending current vehicle-specific exhaust emissions regulations to also cover the carbon footprint of new cars, the researchers said. researchers.
Assumed geographic location of exhaust pipe, fuel and vehicle cycle CO2 emissions. Morfeldt et al.
Researchers looked at emissions from the entire life cycle – from the manufacture of electric cars and batteries to the electricity used in operation. The full effect of phasing out fossil-fueled cars won’t be felt until the middle of the century – and the way batteries are made will affect the extent of the benefits.
The results of the open access study – published in Transport research, part D: transport and environment—Are based on Swedish conditions, but the method used by the researchers can be used to obtain corresponding figures for other countries, based on the vehicle fleet and energy system in each country.
A swift and mandatory introduction of electric cars could bring Swedish passenger car exhaust emissions to approach zero by 2045. The Swedish government has proposed an outright ban on the sale of new fossil-fueled cars from 2030, but that alone will not be enough. will be enough to meet Sweden’s climate targets on schedule, the researchers said.
The lifespan of cars currently on the roads and those that would be sold before the introduction of such a restriction means that it would take some time – around 20 years – before the full effect becomes visible.
– Johannes Morfeldt, researcher in physical resource theory at Chalmers University of Technology and principal author
To have the desired effect, a ban would either have to be introduced earlier, by 2025, or, if the ban is not introduced before 2030, the use of biofuels in gasoline and diesel cars must increase significantly. before that date – in accordance with the revised Swedish “reduction obligation”. The combination of these two measures would achieve zero emissions from passenger vehicles and meet Sweden’s climate targets.
The results of our study show that rapid electrification of the Swedish fleet would reduce life cycle emissions from 14 million tonnes of carbon dioxide in 2020 to between 3 and 5 million tonnes by 2045. The end result in 2045 will depend primarily on the extent to which possible emission reductions in manufacturing are achieved.
A shift from gasoline and diesel cars to electric cars will lead to increased demand for batteries. Batteries for electric cars are often criticized, especially for the fact that they result in high levels of greenhouse gas emissions during manufacture.
There are relatively good opportunities to reduce emissions from global battery manufacturing. Our review of the literature on this topic shows that the average emissions from global battery manufacturing could decrease by about two-thirds per kilowatt hour of battery capacity by 2045. However, most battery manufacturing takes place in abroad, so Swedish decision-makers have more limited opportunities. to influence this issue.
From a climate point of view, it doesn’t matter where emissions take place, and the risk with decisions made at national level to reduce emissions from passenger vehicles is that they could lead to increased emissions elsewhere – a phenomenon sometimes called a “ carbon leak ”. In this case, the increase in emissions would result from an increased demand for batteries, and the risk is therefore all the greater the higher the emissions from the production of batteries.
In this case, the Swedish decision would not have as large an effect on reducing the climate impact as desired. Life cycle emissions would end up in the upper range – around 5 million tonnes of carbon dioxide instead of around 3 million tonnes. For this reason, there may be a need to regulate emissions in vehicle and battery production from a life cycle perspective.
Within the EU, for example, there is a discussion about establishing a common standard for the manufacture of batteries and vehicles – in the same way that there is a standard that regulates what can be emitted. by the exhausts.
However, given Sweden’s low emissions from power generation, a ban on sales of new fossil-fueled cars would indeed lead to a large reduction in the total climate impact, regardless of how the industry manufacturing is developing.
The year 2045 is highlighted because that is when greenhouse gas emissions in Sweden are expected to reach net zero according to the country’s climate policy goals.
Johannes Morfeldt, Simon Davidsson Kurland, Daniel JA Johansson (2021) “Impacts on the carbon footprint of the ban on cars with internal combustion engines”, Transport research, part D: Transport and environment, Volume 95 doi: 10.1016 / j.trd.2021.102807