Do electric cars have a tyre problem?

In this series, we’re unpicking the true story behind electric vehicles to understand whether they are as environmentally friendly as we’ve been led to believe.?

We previously explored how green the national grid actually is.? We learned that Scotland is leading the way in terms of renewable energies with over 88% of the country's power being provided using low carbon solutions. This is compared to England and Wales' rather paltry 53.9%.

Today, we're looking at an unavoidable car component: the tyre.

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Florida’s Broward County approved an ambitious new project: using the unwanted rubber to construct an artificial reef. “Tyres,” a campaigner told the county, “which were an esthetic pollutant ashore, could be recycled, so to speak, to build a fishing reef at sea” (Ecosystems of South Florida,?2008 ). Later that year, locals enthusiastically dumped two million tyres in Fort Lauderdale’s harbour.

As we say in Scotland: “But the best-laid plans of mice and men often go awry.”

The experiment was a spectacular failure, with very little marine life taking to the artificial reef and tyres shifting in the currents, causing damage to the natural coral reefs nearby.?

As the world has become increasingly globalised, and our cities have become sprawling metropolises, our reliance on the humble tyre has only grown alongside fossil fuel use. Yet, they are critical in ensuring safety on our roads, controlling steering, braking, acceleration and a smooth driving experience.

However, as in the 1970s, tyres still pose a massive global environmental concern. Worldwide, an estimated 1.5 billion tyres are produced annually (Mashiri et al., 2015). As they cannot break down naturally, used tyres leach chemicals into the ground or risk catching fire (Mohajerani?et al., 2020).

Every so often, it is claimed that EV tyres produce more particulate matter pollution than ICEs. Primarily made from crude oil, all tyres create emissions in the form of particulates - tiny rubber particles cast off into the road and atmosphere - as they wear down. A key contributing factor to the amount of particulates emitted from tyres is the weight of the car and, with their massive battery packs, some people are concerned that EVs cause extra wear on the tread. There have even been calls to introduce a new tax on EV tyres based on this belief (Express, 2022 ).?

However, scientists have largely discredited these claims. With the recent trend towards bigger and heavier SUVs, modern EVs aren't much heavier than modern ICEs, so the wear on tyre tread is near indistinguishable. Also, as batteries become more and more energy-dense, we'll likely start to see a shift from stuffing more battery capacity into the same space toward producing batteries with similar capacity in a smaller battery, leading to a lighter car.?

Tyre manufacturers are also developing special EV tyres, such as UK startup Enso's EV tyres that wear less without sacrificing grip and extend the vehicle's range more than traditional tyres (Autocar, 2022 ).

EVs may not solve the broader tyre problem, but the wear is broadly on par with petrol and diesel cars (unless drivers get a little throttle-happy!). Luckily, we've found more creative, less destructive ways to recycle tyres than attempting to build tyre reefs since the '70s. For example, waste rubber can be used in construction materials, including concrete, playground and sporting surfaces, and systems to reduce the impact of earthquakes (Mohajerani?et al., 2020).?

Finally, with?most end-of-life tyres already recovered , circularity is the next step.?Goodyear ?and?Pirelli ?have replaced much of the petroleum-based components with renewable materials,?Bridgestone ?has invested in developing an alternative natural source of rubber, and the?Michelin Group ?has ambitious renewable goals and is engaged in recycling end-of-life tyres. These commitments are a step in the right direction, but, as the World Economic Forum has pointed out, circularity requires "unprecedented collaboration" (World Economic Forum, 2022 ). Knowledge sharing and stakeholder cooperation will be the key drivers of progress towards a circular economy for tyres.

Make sure to follow @loveelectric and check back regularly - we post different bits of content three times a week. If you can't wait for the final part of this series, click here for the full article .