A “carbon footprint” refers to the amount of greenhouse gases, CO2 in particular, emitted by a person, organization, activity or object. Carbon footprints are calculated for different periods of time, such as a year. They can also refer to the entire lifecycle of a manufactured product. They are expressed in a unit of mass, such as kilograms or tons, relative to a given unit of time (for example, 10 kg/year.)
This “mass/time” measurement also makes it possible to compare emissions with actions taken to compensate for them. Environmental experts have calculated the number of trees that must be planted to process the carbon emitted by human activity, based on each tree processing between 20 and 30 kilograms of carbon per year. It thus takes one to two new trees by day to compensate for the annual carbon footprint of an average European citizen, which is estimated at 12 tons.
The carbon footprint of a manufactured product is obtained by calculating the total amount of greenhouse gases emitted during its entire lifecycle, from the extraction of raw materials used to make the product, through its period of use, until it is recycled and/or no longer used.
As a useful example, a car’s carbon footprint is calculated based on the energy consumption and CO2 emissions caused by the extraction of gas and other raw ingredients, the production of the various parts, the assembly of the car, the logistics chain it depends on while in use, its recycling, and its end of life. Electric cars have a higher carbon footprint when they first leave the factory than combustion-powered vehicles because of the battery production process. But the scales then tip completely the other way, however, as electric vehicles have a much lower carbon footprint way once they are in use.
According to a European study titled The Electric Vehicle in the Energy Transition, conducted by the Foundation for Nature and Mankind in 2017, over the course of its lifetime, the carbon footprint of a Renault ZOE is nearly 40% less than an equivalent combustion-powered vehicle. This figure is based on an average energy mix: in other words the average distribution of electricity produced by different sources in Europe.
Indeed, the source of the electricity used to power the car has a significant effect on the carbon footprint of an electric vehicle. This type of car obviously emits no CO2 when in use (unlike combustion-powered vehicles,) and charging has less of an effect on the environment when carried out using “low carbon” electricity such as that produced by wind, nuclear, solar or hydroelectric power sources.
The energy mix explains how the carbon footprint of the same electric vehicle can differ across Europe.
In Scandinavian countries, where the kilowatt-hours consumed by the car are produced by hydroelectric dams and wind turbines, electric cars have a lower carbon footprint than in other countries that rely primarily on coal-fired power plants, which emit large amounts of CO2. A new Renault ZOE driven in Poland therefore has a slightly higher carbon footprint than its combustion-powered counterpart, whereas the same car in Norway has a carbon footprint that is four times lower than that of its gas-powered equivalent.
An endorser, even leader, of efforts to decarbonize human activity, France has managed to achieve a relatively low carbon footprint per citizen, largely thanks to its energy mix with a heavy emphasis on nuclear power – which produces much fewer greenhouse gases than thermal power plants – and its use of renewable energies.
These renewable energy sources are particularly encouraged because, according to the study cited above from the Foundation for Nature and Mankind, electric vehicles produce only 22 grams of CO2 per kilometer when their batteries are charged using electricity produced by a wind turbine, and 78 grams of CO2 per kilometer when charged using electricity produced by solar power.
There are many ways for individuals to reduce their carbon footprints, such as by limiting airplane travel to the bare minimum, eating less meat, investing in a “greener” heating system (geothermal or aerothermal,) and sharing the spaces we occupy. When it comes to cars, ecodriving is a guaranteed way to consume less energy on a given trip.
It is also worth noting that the carbon footprint of all electric vehicles, including those already on the road, is expected to reduce over time, given the growing importance of renewable energy sources in the European energy mix. Renewable energy sources should account for 20% of total energy consumption in 2020, as opposed to just 14.1% in 2012.
In the automobile industry, ecodesign can help reduce the carbon footprint by taking the vehicle’s entire life cycle into account. This is why cars like New ZOE are optimized to minimize their environmental impact. The manufacturing process makes use of recycled textiles and plastics, which each vehicle containing 22.5 kilograms of recycled synthetic materials.
In Europe, the ability to produce vehicles and parts on-site decreases emissions that stem from the logistics chain necessary to bring together all the different parts needed to build the vehicles (e.g. transportation, storage of pieces, use of delivery vehicles). Responsible energy use during production, inside the factories themselves, also lowers greenhouse gas emissions.
In the future, technology such as the Smart Grid, an intelligent power grid that emphasizes the use of low-carbon energy sources, and the recycling of batteries – notably the salvaging and reuse of their metals – will help lower emissions even further. The same goes for the repurposing of used batteries and giving them a “second life”, to store energy in different contexts.
On this last point, the study conducted by the Foundation for Nature and Mankind is clear: electric vehicle batteries can definitely be given a second life storing energy outside of the vehicles. This synergy between the automobile and energy industries is increasingly powerful, and it plays an important role in the energy transition and the development of renewable energy.
One of the major issues of our time, taking our carbon footprints into account when making decisions as consumers can greatly alter our impact on the environment. Lowering overall emissions is important, not only to the various companies that have made it a priority in their technological innovations, but also to the world as a whole in our fight against climate change.
Copyrights : inkoly, Olivier Le Moal, golfer2015, OHM Frithjof, Frithjof Ohm INCL. Pretzsch