Are car interiors becoming more sustainable?
29 November 2024
Alongside the transition to electric vehicles, carmakers are focusing more on the sustainability of the materials used for interiors. Tom Hooker, Autovista24 journalist, explores the subject.
When vehicle manufacturers design and produce an interior for their latest models, comfort, functionality and cost are all key factors. However, over recent years, the sustainability of the materials used has become a growing consideration.
Yet replacing these traditional items with greener alternatives is no easy task. For example, plastics have been a low-cost, versatile and durable option for vehicle interiors since the mid-20th century. Replacing these traditional methods with low-impact alternatives is no easy task though.
According to Plastics Europe, between 12% and 15% of the average modern car weighing 1,500kg is made up of plastic materials. It is used in many aspects of a car interior spanning the dashboard, headrests, airbags and seatbelts. This wide usage makes it the second-most-used material in automobile manufacturing.
However, plastic pollution is a growing and ever more apparent problem, in a society wanting to become more eco-friendly. According to the UN Environment Programme, 75 to 199 million tonnes of plastic is currently found in the world’s oceans. Every year, 19 to 23 million tonnes of plastic waste leaks into aquatic ecosystems, the equivalent of 2,000 rubbish trucks.
Rising recycling interests
As well as leather, European carmakers are exploring other sustainable, recycled and natural materials in their vehicles. Brands are also investing in the research and development of new materials, which could further reduce carbon footprints in the future.
Retaining the same interior comfort and quality while using new more sustainable materials is no easy task for car designers. Brands are noticing that customers are becoming more conscious of their impact on the planet when choosing their next vehicle.
‘There is a rising interest in implementing recycled materials and coming up with something holistic. It is a big challenge for material designers because we are not just implementing natural fibres, recycled polyester or polyethylene terephthalate (PET),’ explained Caroline Liehr, colour and trim designer for Škoda.
‘We have to find a material that is recyclable at the end of its lifecycle and does not sacrifice on sustainability, while still having an interesting interior.’
Innovative sustainable materials
The Škoda Elroq, which was revealed at the 2024 Paris Motor Show, uses recycled plastic bottles and recycled post-consumer clothing. These are present in its seat and upholstery fabrics.
‘We implemented a textile which is partly made from recycled cloth. We are not using cloth that is going to second-hand shops, but the ones which are broken and cannot be used anymore,’ Liehr said.
‘It is shredded and spun out again without any use of water or chemicals. After 10 years of working on it, we can bring it to the car. It was a big challenge and a long development process to take this waste material into proper upcycling.’
Other materials used in the Elroq’s interior include recycled PET and regenerated nylon obtained, for example, from old fishing nets and fabric scraps. Elsewhere, in the new Škoda Kylaq, a bamboo-fibre-infused pad is used on the dashboard.
Luxury considerations
Building a sustainable interior is an important consideration for premium brands. Cadillac’s all-electric entry into Europe includes the Optiq SUV, which has a strong emphasis on sustainability inside.
‘Cadillac is focusing on conscious and responsible materials on the Optiq. You have fabrics made of 100% recycled polyester yarns, used in the cabin floor and the floor mats,’ stated Laetitia Lopez, global Cadillac CMF design manager.
‘We also use this material on the matte door pockets and glovebox. The storage on the instrument panel has all been created with recycled contents.
‘We have a decoration made of the same fabric which looks a little bit like carbon fibre, but it is the same recyclable fabric you have on the interior. On the upper level of the Optiq, we are using wood made with wasted newspapers. Everything which is unsold has been reused,’ Lopez highlighted.
Traditional and sustainable?
For some materials, the decision of whether they are sustainable in their sourcing, production and use is less clear.
Leather is also used regularly in car interiors to give a luxurious and comfortable feel. It is durable, breathable, customisable, stain-resistant and easy to clean.
Yet according to the WWF, cattle ranching is responsible for 80% of deforestation in the Amazon. It contributes to soil erosion, increased fire risks and significant biodiversity loss.
Some argue that leather is, however, a sustainable choice, with more advanced processing methods. Efforts have been made over the last few decades to reduce the chemicals, water and energy used in leather production, therefore reducing its carbon footprint.
Furthermore, according to supplier organisation one4leather, if animal hides were not used to make leather, they would be sent to landfills, where they would emit CO2. Without the use of the material in the automotive industry, an additional 644 million kilogrammes of CO2 would be emitted every year. If the use of leather in cars increased by 10%, this would prevent 3.5 million cattle hides from going into landfills, in turn saving over 64 million kilogrammes of CO2.
Ultimately, however, some carmakers will decide to use vegan leather in their vehicle interiors. This mimics the look and feel of traditional leather but is made up of different materials.
Utilising alternatives
Volkswagen (VW) is exploring leather alternatives in its car interiors. Cooperating with start-up Revoltech GmbH, they will research and develop sustainable materials based on industrial hemp. This could be used in VW models from 2028.
The material is made from 100% bio-based hemp and uses residues of the regional hemp industry. It can be produced on existing industrial plants and recycled or composted at the end of its service life in a vehicle.
Another VW Group brand, Audi, is already using sustainable materials on some models. In the new Q5 Sportback, materials such as Cascade upholstery and Dinamica microfibre are offered. Both are primarily made from recycled polyester.
Casade upholstery is also used in the new Audi A5. The waist rails, inserts, and armrests of the door panels in the sedan are based on recycled plastics.
Circular economy
Meanwhile, BMW Group is placing a large focus on circular economy to design more resource-efficient vehicles. By reusing valuable resources, the German OEM aims to reduce its dependence on critical primary raw materials, which are rising in price. In turn, this will reduce their vehicles’ carbon footprint.
The BMW i Vision Circular concept showcases this philosophy. The vehicle was designed to use the least number of components and materials possible. The concept car is built from 100% recycled or bio-based materials and is fully recyclable.
Also in the BMW Group, the all-electric MINI Cooper now offers a completely animal-friendly and leather-free interior using sustainable, partly recycled materials. In particular, the model’s seat surfaces are constructed with knitted 100% recycled textiles.
The dashboard and armrests are made with a knitted textile too, namely a recycled polyester yarn. This is produced in a process that turns over 90% of recycled polyester fibres into fabric.
Around 98% less water is used compared to cotton in this method. It also reduces CO2 emissions by around 80% compared to conventional polyester processing.
Using plastic waste
In the Stellantis stable, the new Jeep Compass Upland 4xe plug-in hybrid uses recycled plastic in components of the dashboard, central tunnel, doors, floor mats and interior headlining. The SUVs seats are trimmed with bio vinyl and Seaqual fabric, a material made with plastic waste recovered from the sea.
At Opel, customers have the option to drive ‘vegan vehicles’. This means the interior trims in these models are made of vegan and animal-free materials. Furthermore, all interior trims in the brand’s current battery-electric vehicle are exclusively vegan.
Meanwhile, Citroën have put a vehicle life cycle analysis procedure in place, where a vehicles’ total environmental impact is measured, from design to destruction.
In 2018, green materials accounted for around 30% of the total polymer mass in the carmaker’s vehicles, compared to an average of 6% in 2007. The new Citroën C5 Aircross contains 31% recycled and natural materials.
Elsewhere in the group, Fiat envisions a ‘less is more’ approach to building cars. The brand wants to remove redundant parts and reduce polluting materials, such as the foam in seats.
An ambitious target
Mercedes-Benz has set a target of a fully networked and net carbon-neutral fleet of new vehicles in 2039. Called ‘Ambition 2039’, the marque is working on closing material cycles, significantly increasing the proportion of recycled materials in its vehicles and researching new sustainable materials.
Starting in 2025, Mercedes-Benz will offer only sustainably produced and processed leather in all model series. The brand is also conducting research into animal-free alternatives to genuine leather.
Furthermore, Mercedes-Benz offers leather-free trim options in its vehicle interiors, including the A-Class. This includes a microfibre nonwoven fabric that consists of up to 73% recycled material. It is used in the vehicle interior on the seat cover, steering wheel, centre console and door panel.
The fabric used in some of the carmaker’s models also features recycled materials. For example, the floor coverings in the EQS use nylon yarn that comes from recycled carpets and recycled fishing nets.
Carbon neutrality
Renault Group wants to reach carbon neutrality in Europe by 2040 and worldwide by 2050.
The Emblème concept car represents this approach. Unveiled at the Paris Motor Show, it uses 50% recycled materials. Almost all of the materials used in the demo model can be recycled at the end of their life.
Dacia, another Renault Group brand, has decided to stop using leather and decorative chrome in all its models. In both cases, this is for environmental reasons.
Natural materials
Volvo uses natural materials such as a wool blend in its upholstery. It is made from 30% natural wool fibre and 70% recycled polyester. The manufacturer also uses woven flax, a natural and renewable fibre that comes from linseed plants, which need very little water to grow.
The material requires less energy to make and produces less emissions compared to regular plastic parts. Responsibly sourced wood is present in Volvo’s interiors too.
On top of this, the brand has developed its own material called Nordico. It consists of recycled polyester from PET bottles and PVC made from bio-attributed material from Swedish and Finnish forests. PVC is also used in its ‘particle décor’ option. In its denim interior décor, the short fibres generated from shredded jeans are used.
By 2025, Volvo aims for 25% of the material in its new cars to consist of recycled and bio-based content. This is part of the marque’s ambition to be a fully circular business by 2040.
The carmaker is also aiming for all of its immediate suppliers, including material suppliers, to use 100% renewable energy by 2025.
Ultimately, the rethinking of the use of plastics, leather and other materials used in car interiors is of high importance for the automotive industry. With the EU targeting no net emissions of greenhouse gases by 2050, the prominence of this topic will only grow in the years to come.
