How eco-friendly is an electric car compared to a fuel-efficient diesel car? And what impact does the manufacture of electric car batteries have on the environment? It can be confusing when buying a car to try to make an eco-smart choice, since one car model can have vastly different emissions figures depending on how they are calculated. To produce a more accurate overview, researchers at RISE conducted a study on electric vehicle life-cycle analyses, and proposed guidelines on how the analyses should be carried out.
Although one of the more common electric cars on the market today can emit anything from 13 grams to as much as 243 grams of CO2 per kilometre (depending on how emissions are calculated), the scientific community is generally in agreement that electric cars provide definite benefits in terms of CO2 emissions compared to petrol and diesel cars.
The fact that an individual vehicle can have completely different emissions results is largely because no established standard is in place concerning how an electric vehicle life-cycle analysis should be conducted. To understand how the results could be so different, RISE pored over more than 100 LCA studies on electric vehicle emissions within the framework of the ‘Energy Efficiency in the Transport Sector’ project, funded by the Swedish Energy Agency.
– “LCA is a powerful tool, but when it comes to determining environmental impact, a fair and transparent comparison must be made. It also has a lot to do with the way we view future energy supply,” says Patrik Klintbom, researcher in sustainable transport at RISE.
Electric vehicles evolving rapidly
An LCA study is always carried out with good intention, but the data on which it is based may be outdated owing to the rapid technological development of electric vehicles. Batteries are consistently improving, and their manufacture is becoming increasingly sustainable. These factors may mean that the data used in an LCA study become outdated in a very short time.
A vehicle life-cycle analysis can roughly be divided into four parts: Raw material extraction, manufacture, use and disposal of the end-of-life vehicle. When it comes to the use of the vehicle, the impact of carbon dioxide emissions is frequently discussed in terms of electricity production. Because electric vehicles are new consumers in the electricity market, it is sometimes thought that the electricity will need to come from imported coal power, since domestic non-fossil electricity will not be sufficient. But even if some of the electricity in electric vehicles were to come from coal power, Patrik Klintbom believes it is important to see the direction we are heading:
– “Current electric systems contain a lot of fossil energy, but future production will be completely different. Solar and wind power are growing steadily. In 20 or 30 years, when there are plenty of electric cars on the roads, the situation will be totally different.”
It is very important to be clear about the context
Clarity regarding calculation methods
A conclusion drawn by Patrik Klintbom and colleagues Patricia van Loon and Linda Olsson is that it is important to be transparent about how a life-cycle analysis has been conducted.
– “It is very important to be clear about the context. If I conduct an LCA based solely on purchasing electricity for my electric car from coal power plants, there will naturally be high figures relating to carbon dioxide emissions. The LCA figure will be correct for that individual vehicle, but says nothing about the general environmental impact of electric cars.”
The RISE project also involved formulating guidelines for LCA studies on electric vehicles. They will serve as a solid guide when carrying out LCAs and are geared towards individuals working with development in the automotive industry. The guidelines describe important aspects to consider and the methods available. The expected transformation in electricity production is an example of something that must be included in calculations to obtain a fair overview. The recommendations also stress the importance of finding out which materials the vehicle contains. It involves time-consuming work which requires going all the way back to the mine to determine the impact of lithium mining, for example.
Impact of batteries
Batteries account for a large part of the carbon footprint of electric vehicles. When conducting an LCA for the battery alone, a large proportion of the vehicle's total emissions can be accounted for. Therefore, one of the recommendations involves conducting a detailed analysis together with the supplier. Another aspect is to include the emissions generated by the construction of charging infrastructure.
Everything points to LCA studies becoming increasingly important in the future.
“It has been mentioned that life-cycle requirements for vehicles will be introduced in the EU in the coming years. And new definitions for environmentally-friendly vehicles may include a life-cycle component, where, for example, cars with large batteries may be penalised,” says Klintbom.
