The innovation that has emerged from the World Solar Challenge

The Bridgestone World Solar Challenge has been run and, at least in one of its two classes, won for another year.

And, once again, the trophy is moving to a Dutch-speaking part of the world. The Belgian Innoptus team claimed a second consecutive victory with an inspired design incorporating a top-of-the-line battery storage unit from Silicon Valley, a cleverly designed silicon PV solar array, and a novel aerodynamic profile.

Together, it helped that team stave off the challenge from two cross-border rivals in the 3,020km solar vehicle endurance test from Darwin to Adelaide.

But innovation was everywhere to be found. Top Dutch Solar Racing debuted a perovskite solar cell array developed in partnership with Oxford PV.

Two teams – the University of Minnesota (USA) and Team Sonnewagen Aachen (Germany) – constructed their motors in-house. A new team from Deakin University in Geelong built its car from basalt fibre, instead of carbon; volcanic rock, rather than graphite mixed with plastic polymers.

Teams chose to embrace regulations allowing three wheels and met varying degrees of success. Others found the extra point of contact running a more conventional four wheels to be detrimental.

The event emerged from the post-pandemic world with a question of relevance hanging over it.

Electric vehicles are now here. So what’s the point of building conceptual solar cars when I can roll an EV off the grid today?

Before answering that, the World Solar Challenge’s long-serving event director Chris Selwood says the collective memory of what the event is about and how it operates was “completely lost” after the pandemic.

“All across the country, we’ve been re-educating the authorities on what we’re about, and how we have evolved in many cases with those authorities, their operational structures,” he tells Cosmos.

Selwood acknowledges there is a problem that an event showcasing and advocating for sustainable technology is hamstrung by ties to non-renewable energy.

“As a biennial event with so many international participants, international travel is itself carbon-intensive, and we feel the value in bringing the attention of the public to the imperatives of sustainable transport is a reasonable balance in that context,” he says.

“We know that the environmental motivation is high on the agenda of our participants. The question of how the event can address sustainability is rising to the top of our agenda.

“We’ve seen more efficient vehicles being used as support vehicles, I think in two years, we might be in a better position to have electric vehicles and support vehicles for the officials, that would be a good way towards it.”

This year the top four finishers were the only ones with a new Amprius battery pack which had about 30%-50% more energy density than their competitors. These batteries were within the rules, but probably created a ‘two speed’ competition at the front of the field.

But less environmentally sound materials were outlawed this year.

“In terms of solar cells, if you had the money, you could have the space-grade gallium arsenide cells, but the top teams came to us and said ‘we don’t want to spend $2 million on a solar array, it’s time that you banned gallium arsenide’. And my pushback was, ‘I don’t want to ban anything,'” says Selwood.

“But gallium arsenide has a huge environmental toxicity impact. These things are made to be deployed in outer space. On the basis of their toxicity, we said we won’t use those anymore.

“Our regulations define the battery storage limits on the electrochemical compound. With this new [Amprius] technology that we’ve got out of Silicon Valley, it’s quite clear that the electrochemical compound falls within the regulations.

“The fact that there’s about 30% more energy density, because of the nanotechnology they’ve employed in the construction came as a surprise, and as a delight to those that were able to get hold of it.”

Selwood expects the energy storage balance in this high-calibre competition to be restored for the 2025 event. Whether that’s through regulation, or teams simply buying up this new technology, remains to be seen.

“The first 4 teams were the four that had that technology. Clearly, there’s going to be a balance brought back in that space in the future.”

The best solar car teams in the world exist in a 30,000km² patch in northwest Europe. A team from this region is almost always a short-odds favourite to win international solar races and 2023 has been no exception.

Compare that to teams from Australia. In 2023, only one of seven teams crossed the Adelaide finish line without having been put on a trailer. Kudos to Western Sydney University for finishing ninth, but for a massive event hosted down under, Australians have never seemed likely to win. Not since the sole Aussie victory in 1999 anyway.

Selwood says turning that around will require a major change in attitude towards solar racing from the nation’s universities.

“There’s a different worldview in Europe. The dean of the University of Eindhoven reckons that their institution’s involvement in the World Solar Challenge saved him millions of euros in marketing,” Selwood says.

“We’ve seen universities who’ve taken a whole-of-school approach to their involvement in the World Solar Challenge – where the business studies students have a live exercise on fundraising and sponsorship procurements, where the arts industrial design people have had a hand in the design of the car.

“The University of Adelaide team, they have done so well, but they share a workshop with other projects, they share facilities with other projects, so they don’t have any clear air around what they’re doing. The support up through the structure of the university is something they need to fight for every step of the way.

“I think unless an institution embraces something like this as a whole school approach, then you’re going to be struggling.”

Selwood says a domestic solar event in Australia between the biennial World Solar Challenge would allow Australian crews to create more cohesive team structures and trial their technology in the same way European teams do in the European Solar Challenge. Such an event – potentially run on a track as with other domestic solar events – could also be open to school teams.

“A track event also has a much lower risk profile so we can get school teams involved,” he says.

The Bridgestone World Solar Challenge concluded this week with the overall event and Challenger Class being won by Innoptus. Judging for the Cruiser Class – a points-based category where solar passenger vehicles are scored on their person kilometres, energy efficiency and practicality will be held in Adelaide on Saturday.