Could wireless charging fuel electric cars?

17th February 2022

The number of standard electric vehicle (EV) chargers on UK streets rose by 70% between 2019 and 2021. Sounds promising, except that the number of plug-in electric cars grew by 280% over the same period - and battery powered cars jumped 600%. A UK car industry lobby group has warned of a "growing regional divide" in access to EV charge points which threatens the government's target for all car sales to be electric by 2035.

You're reading the Imagine newsletter - a weekly synthesis of academic insight on solutions to climate change, brought to you by The Conversation. I'm Jack Marley, energy and environment editor. This week, we're asking how charging infrastructure can keep up with the transition to battery-powered EVs.

Swapping petrol and diesel vehicles with those powered by electric batteries would take a significant chunk out of the UK's total emissions. About 12%, according to research by George Milev and Amin Al-Habaibeh at Nottingham Trent University. So what do all motorists need to make the switch?

"We cannot simply ban everyone from getting a petrol car, install a charging point in every neighbourhood and think that will be sufficient," say Miguel Valdez, Matthew Cook and Stephen Potter, transport experts at the Open University.

A third of UK households reportedly lack a dedicated parking space where they might install a private EV charging point. "Would it be feasible to install on-street charging points next to all such houses?", they ask. "Even if it were, what would that do for street clutter? How would the pavements change if they became criss-crossed by electric wires?"

The team think that wireless street charging might allow EVs to top up their batteries in the future, and are leading a trial to find out more.

Smart roads, which charge the EVs driving on them, are being trialled in Sweden. Rick Greenough, a professor of energy systems at De Montfort University writes about the pilot scheme outside Stockholm, where two kilometres of road are fitted with charging rails which extend the range of EVs in a similar way to Scalextric tracks.

This technology could reduce the need for so many dedicated charging points if rolled out on a significant scale, but Greenough doubts smart roads have much to offer the EV roll-out in their current form.

"To prevent electrocution or damage by the elements, the live rails are hidden from view. This means that vehicles can only begin charging when [a pickup arm attached to the bottom of a vehicle] is inserted into the rail slot. One can imagine the damage that might be caused to the road and the vehicle if the pickup fails to disengage cleanly before the vehicle attempts an overtaking manoeuvre," he says.

Like the team at the Open University, Greenough thinks that wireless charging is likely to be more helpful.

"Conductors that are set into the road create an electromagnetic field, which then transmits energy to coils mounted to the bottom of vehicles. Such technology is already used by wireless phone chargers and can be adapted on a bigger scale for electric vehicles," he says.

One day, it's possible that the 5G network - the latest generation of technology capable of beaming internet connection to phones via radio waves – could be repurposed to transmit electricity wirelessly. Elena Gaura is an associate dean for research at Coventry University along with James Peter Brusey, a professor of computer science. They write that the 5G network could deliver the early 20th-century dream of pioneering engineer and inventor Nikola Tesla and create a wireless energy grid.

"Because 5G relies upon a dense network of masts and a powerful series of antenna, it's possible that the same infrastructure, with some tweaks, could beam power to small devices," they say. "But the transmission will still suffer from the key drawback of Tesla's towers: high energy wastage." And it could be a long time indeed before the technology is capable of running something as large as a car.

If all this sounds fanciful, perhaps we should reconsider the notion that electric cars and other EVs are the primary climate solution in transport in the first place. Alexandre Milovanoff, a postdoctoral researcher in environmental engineering at the University of Toronto in Canada, studied the 260 million passenger vehicles in the US and found that the country will need to be driving 300 million EVs by 2050 to keep up with growing private car ownership. That's 90% of the entire projected fleet.

"Even the most optimistic projections from the International Energy Agency suggest that the US fleet will only be at about 50% electrified by 2050," he says. "[Such] a rapid pace of electrification would severely challenge the electricity infrastructure and the supply chain of many critical materials for the batteries, such as lithium, manganese and cobalt ... I am not saying it's impossible, but I believe it’s unlikely."

Milovanoff asks whether we really need so many private EVs on roads. Decarbonisation might more easily be achieved by dramatically expanding low-carbon public transport and cycling and walking infrastructure, alongside a push to convert fossil fuelled cars to EVs.

In the UK, as in the US, it would seem an electric car in every garage is a relatively inefficient way of cutting emissions from transport.

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This article is from the Imagine series at The Conversation web site