Reducing what is known as the"carbon footprint" or"carbon balance" is a priority for all companies today. This reduction is complex because it concerns all activities. For the automotive sector, it is relatively easier to focus on the footprint attributed to products, i.e. the 'load' of emissions that each car accumulates throughout its life and which includes everything from the extraction and processing of raw materials to use and disposal.

Since not all emissions are carbon dioxide, the universal parameter for calculating them is what is known as CO2e or 'CO2 equivalent', a method in which other emissions are also compared and 'converted' into CO2 to give a single reference value. And that represents several tonnes per car.

How can we reduce the 'load' car by car?

Having established the benchmark, we move on to the countermeasures: as we have said, the operation concerns the entire supply chain, including supplies, transport, production and the direct emissions that result, those produced 'at the tailpipe' and not only, there are also those produced by the wear and tear of tyres and other wearing parts that are taken into account.

So it's clear that, in terms of this principle, the switch to electric traction, which eliminates almost all direct emissions at a stroke, especially when based on renewable energy sources, is the ultimate goal for all manufacturers. But what can be done about the other items on the list?

La représentation graphique des émissions de CO2e de la Polestar 4

Electrified brands have an advantage: manufacturers like Polestar, which recently published its sustainability report on the new Polestar 4, claims that the car currently has the lowest carbon footprint of any car on the scene, between 19.4 and 21.4 tonnes depending on the version. That's a lot on the face of it, but very little over an estimated period of eight or ten years or more.

The fact that the range is 100% electric obviously contributes to this, but the Swedish manufacturer has taken many other precautions to achieve it. Here they are:

Green energy at the factory

The first step is to use sustainable, certified electricity, much of which is self-generated by its own photovoltaic systems. Today, many factories have solar farms that cover up to 50% of their internal energy needs. In the case of the Polestar 4, this is Geely Holdings' SEA plant in Hangzhou Bay, China. It combines externally supplied certified hydroelectric power with self-generated photovoltaic energy.

Decarbonised raw materials

The second point is the increased use of low-carbon metals: in this case, mainly aluminium from foundries that use hydropower to supply themselves with electricity, and an increasing proportion of recycled 'short-chain' aluminium.

Batteries

Aluminium alone accounts for almost 25% of the carbon footprint, while steel and iron account for 20%, but for an electric car, the largest share is still accounted for by batteries: the production and refining of the materials needed to build them account for 36% to 40% of the final balance. The development here ranges from the internal chemistry of the batteries to energy management, which contributes to reducing both consumption and emissions during the production phase.

Careful design

Reducing the carbon footprint is no longer an objective to be achieved 'on the hoof', but one of the fundamental criteria underlying the development of each new model. The study points out that the emission values of each phase and each individual component, the weight and origin of raw materials, influence technical, production and even stylistic choices. 

The design must take these requirements into account, while seeking maximum constructive simplicity and effective aerodynamics, capable of guaranteeing maximum efficiency and therefore energy savings during use.

Polestar 2 MY 2024

Polestar also points out that on its other model, the Polestar 2, as well as improving range and performance, constant efficiency has enabled CO2e emissions to be reduced since production began in 2020. With the current MY2024, the total estimated saving since launch has reached 12%, or around 3 tonnes in three years, and the car now boasts values of between 22.4 and 23.1 tonnes, depending on the version.

Gallery: Zero-emission factories, this is how it can be done