Could sewage-powered car be motorsport's sustainability solution?
As motorsport attempts to reduce carbon emissions and become more environmentally sustainable, a group of engineers may have come up with a novel solution - and it's found in human waste.
They have developed a prototype race car made from sustainable materials, that is powered by... sewage.
Or rather, sewage treatment technology which involves microbes feeding on waste producing hydrogen as a by-product - and it is this hydrogen which produces fuel for the car.
The Warwick Manufacturing Group (WMG), which includes students at the University of Warwick, is behind the prototype, working with sewage treatment technology being trialled at Severn Trent Water.
They believe the car could be out in the mainstream in as little as five years, though they acknowledge there are still significant hurdles to overcome.
"There's been a real push for electric vehicles and it's fairly clear that there has to be other sort of energy in the mix as well, so hydrogen has a part to play," Dr James Meredith, chief engineer at WMG, told BBC Sport.
"It comes from a long period of research. A microbial electrolysis cell is essentially a device used to clean water and microbes grow on recycled carbon fibre, eating the sewage. During that process, they produce hydrogen as a by-product."
WMG will use the car to try to break several land speed records, including fastest standing and flying starts over a mile and a kilometre.
Dr Meredith hopes the hydrogen technology will produce the same amount of power as petrol. But the challenge, particularly when developing a car suitable for racing, is reducing the size of the storage tanks.
"Hydrogen is a good fuel. It's clean burning," he said.
"We're starting to scale up the process and seeing just what we can do on an industrial scale. So, then in terms of actually running the car on hydrogen in a race, the biggest challenge with hydrogen is the shape of the storage tanks and how much volume it takes up."
Formula 1 has made steps to make the sport more sustainable in recent years, after announcing in 2019 that it hopes to become carbon neutral by 2030.
That includes more efficient engines and tweaks to the calendar to reduce the distance freight travels by plane.
In 2026 new regulations will be introduced, which include smaller, nimbler cars and 100% sustainable fuel.
In April, the electric car racing series Extreme E will switch from electric to hydrogen-powered cars, renaming itself Extreme H.
German manufacturer BMW has announced plans to put a hydrogen car for domestic use on sale from 2028.