For the same vehicle models with different powertrains, the carbon footprint of the battery-powered E variants is already better than those of the corresponding vehicles with internal combustion engines. In addition, the electric vehicles offer a higher CO2-saving potential in all phases of the product cycle.
Furthermore, it is of crucial importance for CO2 emissions whether the propulsion energy is generated from fossil or regenerative sources. This is the result of a certified life cycle assessment (LCA) of the Volkswagen Golf, which compares the CO2 emissions of the different vehicle versions with either an electric or an internal combustion engine.
In summary, the current Golf TDI (Diesel) emits 140g CO2/km on average over its entire life cycle, while the e-Golf reaches 119g CO2/km.
It is evident that in the vehicle with an internal combustion engine most of the emissions occur during the use phase, that is, in the supply chain of the fossil fuel and the combustion. Here the Diesel reaches 111g CO2/km. A corresponding vehicle with electric drive emits only 62g CO2/km during this phase, which results from energy generation and supply.
In contrast, most emissions from the battery-powered electric vehicle are generated in the productions phase. According to LCA, a Diesel here generates 29g CO2/km, while 57g CO2/km were determined for a comparable e-vehicle. The battery production and the complex extraction of raw materials are responsible for this. These emissions account for almost half of the CO2 emissions of the entire life cycle. During the use phase, CO2 emissions depend on the sources of energy production. They decrease all the more, the more regenerative energies are available.
Life cycle assessment is an intricate, complex, and internationally standardised procedure to research the ecological balance sheet of vehicles. Among other things, the carbon dioxide emissions are investigated during all product stages of the automobile:
With the findings from the "Life Cycle Assessment", Volkswagen can derive additional emission-reducing measures for "Life Cycle Engineering" and specifically optimise the CO2 balance.
Improvements in lithium-ion battery technology and supply chain optimisations lower the carbon footprint during battery manufacturing for the first ID. model planned for 2020 by more than 25% per kilowatt hour (kWh) of battery capacity compared with the e-Golf. When using regenerative energy, the reduction potential is almost 50%.
By far the greatest potential for reducing CO2 emissions arises from the source of energy applied during the use phase. If electricity for driving during the use phase is obtained exclusively from renewable sources, CO2 emissions of 62g CO2/km in today’s EU electricity mix will drop to just 2g CO2/km.
Against this backdrop, since the beginning of the year, in Germany the subsidiary Group Elli (Electric Life) has been offering customers and third parties “Volkswagen Naturstrom”, which exclusively comes from renewable energy sources.
Recycling the vehicle offers further opportunities to reduce CO2 emissions through the circular economy. Thus, a pilot plant for recycling is currently being built at the Volkswagen location Salzgitter. There, from end-of-life batteries - that is, batteries that no longer store enough energy due to aging - a new raw material (black powder) for the cathodes of new batteries is to be obtained. This results in a potential CO2 reduction of up to 25%. However, the group does not expect significant amounts of batteries for industrial-scale recycling until the end of the 2020s.
The decarbonisation index (DKI) measures the CO2 emissions of an average vehicle of the Volkswagen Group over its life cycle. The DKI is measured in tons of CO2 equivalent per vehicle. In 2015, the figure was 43.6 and, according to the Volkswagen Group's target, it should decrease by 30% by 2025.