technology transport

Sustainable materials for Volta’s electric trucks

All manufactured products have an embodied carbon footprint – the carbon emissions from their production and from the extraction of the materials required. Electric cars might have no emissions in operation, but they still have embodied carbon. Because of the metals in the battery, they can sometimes have slightly higher embodied carbon than their fossil fuel counterparts.

That’s no reason to think that electric vehicles are a waste of time. Unless you’re running it entirely on pure coal power, it will produce fewer emissions over the course of its lifetime, as well as less noise and air pollution. Still, to be truly sustainable, vehicle manufacturers need to address the emissions from production. This will become more important over time – once all vehicles are electric, embodied emissions might become the main source of emissions from cars.

I’ve written more about embodied carbon in cars here, but today I wanted to mention a specific example. Volta Trucks is a Swedish start-up, now based in the UK to tap into car manufacturing expertise. Their ambition is to create the world’s most sustainable truck, and they recently unveiled a 16 tonne urban delivery vehicle. In order to reduce the impact of manufacture, the truck uses panels made of flax.

Flax is a versatile plant, used to make linen, banknotes and many other things. Volta have combined it with biodegradeable resins to produce the bodywork for their electric trucks. It’s a material that was originally developed by the European Space Agency and is often used in motor racing. This is the first time it’s been used in a commercial vehicle – though not the first time designers have experimented with it, not the first time I’ve mentioned it on the blog. I wrote about cars made with flax in 2014 and 2017.

The flax replaces steel, with a major carbon saving in the process – it is “almost” carbon neutral over the course of its lifetime. The materials are grown rather than extracted, so it is a renewable resource. It is lightweight without compromising on strength. It’s also biodegradeable, though not under normal working conditions.

There’s also a nice example of biomimicry here, or drawing design inspiration from nature. One innovation that Volta have used is a system of ribbed reinforcements in the material, inspired by leaf veins. The ribs give it the same strength as carbon fibre panels, but without shattering dangerously as carbon fibre is prone to do when broken, and with a quarter of the carbon emissions.

It’s good to see flax panels move from experimental prototypes to a commercial vehicle, and to see a company that is thinking through the challenge of net zero from a variety of angles.

One other thing that’s also worth mentioning is that Volta are designing their vehicle not just to deliver low emissions, but to work in the context of a low carbon city. Founder Carl-Magnus Norden says that he wants their truck to be “a friend of the zero-emission city.” One aspect of a future city is a lot more walking and cycling, and so the truck has been designed with the safety of pedestrians and cyclists in mind.

This is quite an intriguing idea and I look forward to hearing how other manufacturers respond to the changing conditions of a low carbon city.

2 comments

  1. Perhaps the most important change in production emissions will be switching current processes to renewable energy for most of the other aspects of vehicle production? It would be very interesting to know if any decent studies exist on what footpriints could be if using renewable electricity for producing and manufactiring with recycled steel (which is fast becoming the norm: we reached ‘peak virgin steel’ some time ago), and other metals and plastics?
    I think some caution is warranted before getting too starry-eyed about flax-reinforced biodegradable resins. Is there good data that shows this has better footprint than plant-fibre-reinforced thermoplastic options (which can quite readily be reprocessed into other articles; albeit lower performance) or even used as fuel (in the right circumstances this might be a lot better than biodegrading thermoset resins)? Also is flax a good fibre to reinforce with, environmentally? Crop yields are much lower than say hemp, which also copes much better with the materials processing, and this has land use and other footprint implications. Also I’m not sure that replacing the panels is too significant in the overall scheme of things. I suspect these aren’t actually major structural parts. What fraction of overall mass and/or footprint do they represent?. Composite-structures engineers are also likely to be unimpressed over claims of innovative rib design or avoiding splintering in carbon composites: these (and full production use of flax or other plant-reinforced plastics) are all very ‘old hat issues’, so Volta may be marketing much more than innovating here.

    I think all this shows that trying to transform our current highly unsustainable sets of production processes is a big challenge that needs careful whole-systems thinking – but that doesn’t make it any the less necessary and urgent, and it’s to be welcomed if Volta really are trying to improve.

    I also feel rather bad at carping about technical points while I retain huge admiration for all your other articles, particularly many of your most recent ones!

  2. No need to feel bad about asking good questions – the best kinds of comments are those from people who know more about the story than I do and add value to my observations.

    You’re right that plant based plastics aren’t revolutionary, but this is still the first time flax has been used on a commercial vehicle, and why I give it a mention. As always with these kinds of stories, it’s not necessarily that Volta have done something so incredibly remarkable, but that the innovation is emblematic of the kind of change we need to see in materials. We need car companies, and indeed all manufacturers, to think through their materials from a circular economy and an embedded carbon perspective.

    Yes, using renewable energy in production is also a major step towards lower emissions. The BMW i3 is made in a custom built factory that is 100% renewable energy powered, and all its panels and thermoplastics are made with 100% renewable energy too. The i3 a very comprehensively thought-through project, especially coming from a legacy auto company.

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