By Jeremy Williams

I’m aware of four different ways to charge electric vehicles without stopping to plug in. All of them have been trialled and some are being adopted more widely. I’ve written about all four at some point:

• Overhead cables – somewhat obvious, given that trams and trolleybuses operate on this system already. Not something that cars will use, but a real opportunity for trucks and coaches on highways. There are plans to use this in Sweden, while a proposed trial in the UK has gone strangely silent.
• Wireless charging – the most promising option for short stays, such as bus-stops and taxi bays, like the cabs in the photo at the top, pulling in to wirelessly charge in Gothenburg. Similar technology can also be deployed to create charging lanes along the road.
• Integrated solar – you need a lot of solar power to move a car, so it’s not providing live power as you drive. But as several start-ups have shown, you can make an efficient car that never needs to be plugged in if you remember to park in the sun. (Why all EV manufacturers aren’t fitting solar roofs, I do not know.)
• Charging slot – a company in Sweden demonstrated a giant version of Scalextric, where EVs lowered a charging arm into a groove down the road. It’s mechanically complicated and was the least likely to succeed in my view – and indeed, the website of the firm that developed it now delivers a 404.

All of these technologies have pros and cons, but why do we want them in the first place? What’s the big advantage of being able to charge on the go?

It might be tempting to start with the convenience of the driver, and say that it would make range anxiety a thing of the past. It would reduce the number of stops on long journeys and you wouldn’t have to wait your turn at a charging point like we had to do at the service station at the weekend. It would cut long charging times, though those are on the way out anyway thanks to faster charging systems. But I don’t think driver convenience is the big win.

The most important reason to invest in charging on the fly is that it reduces materials. If you can charge up along the way, then you don’t need to carry all your power with you and you can reduce the size of the battery in the vehicle. The first study of wireless charging in real-world conditions (in Sweden, naturally) found that battery sizes could be 70% smaller for most EVs.

That has multiple benefits. For a start, batteries are what makes EVs more expensive, so smaller batteries will make them more affordable. Vehicles would be lighter, which means they need less power and do less damage to roads and infrastructure. Lighter vehicles are more efficient and will be cheaper to run as well as to purchase. For goods vehicles, charging on the go would save weight that could then be used for cargo.

The study suggests that vehicles taking sips of electricity throughout the day makes it easier for the grid to manage the charging needs of electric cars. It reduces peak demand, that moment when people get home from work and all plug in their vehicles at the same time.

Here’s another knock-on effect: If batteries are smaller, that reduces pressure on the world’s lithium supplies, cobalt and other resources that underpin clean transport. Perhaps that’s the most significant effect of all, as there is a real possibility that low-carbon technologies could drive a new wave of extractive industry abuses.

We should prioritise technologies that use resources efficiently, in a circular economy, and that reduce the risk of repeating past mistakes. While it won’t be for everyone and everywhere, charging EVs on the go might be one of those technologies.

Is it going to happen? Depends on where you are. As you may have noted, three of the four examples in those bullet points are from Sweden, which has spotted this opportunity. So the answer is already a yes for Sweden, and probably for Germany, Denmark and Norway.

Solar is less promising in Northern Europe, but that’s going to be the big one in many other places – most of the world’s population lives in places with good solar capacity. Cars will have a different place in the transport systems of the future, but I suspect that eventually, small and lightweight vehicles with in-built solar will dominate the roads of the global south.

First published in The Earthbound Report.