Are coffee grounds about to become a best-selling biofuel?
Every day, the UK consumes around 70 million cups of coffee with thousands of tons of ground coffee going to waste.
Arthur Kay founded the coffee recycling company bio-bean which turns used granules into biofuel pellets.
More than 500,000 tons of ground coffee waste is produced every year in the UK, and for now bio-bean's factory can recycle up to a tenth of it.
More than a thousand different coffee shops, restaurants, offices, train stations and shopping centers have signed up to the scheme, and many of them buy the biofuel pellets to heat their own buildings.
The bio-bean team pick up coffee waste from 300 locations across the UK.
"Our factory processes about one in 10 cups of coffee produced in the UK -- that's about seven million cups a day," says Kay.
The biomass pellets and briquettes (pictured) can be used for anything from warming pizza ovens to heating entire buildings.
At the moment, most of the pellets are sold back to the coffee shops where they came from, creating a circular economy.
A burner fueled by bio-bean briquettes at London's Borough Market. "Two and half years ago, this was a sketch on the back of a napkin," says Kay. "Today, it's a ground-out reality which could power the future."