In an interview with the Guardian, founder Arthur Kay said he came up with the idea when he was studying architecture at UCL in 2012. He said was looking at closed loop waste-to-energy systems for buildings and happened to select a coffee shop.

Kay said he discovered that London produced 200,000 tonnes of coffee waste per year and that coffee had oil content in it.

The technology Bio-bean uses is straightforward. Coffee grounds are dried, a patented biochemical process extract oil and the remaining material is then turned into biomass pellets used to be burned in boilers.

Describing the technology, Kay told the Guardian: “Imagine you have a pile of coffee grounds. You dry them, then we have the patent for the bit in the middle that allows us to extract oil from it. It’s a biochemical process, a solvent that you evaporate through what’s called ‘hexane extraction’. By weight it is about 15-20% oil. The remaining 80-85% is then turned into bio-mass pellets used to be burned in boilers. The solvent is also 99.9% recyclable, meaning it can be used over and over.”

The company plans to set up a large-scale waste processing site in Edmonton, North London, by the end of the year. It will be capable of processing 30,000 tonnes of coffee waste a year. Major coffee companies and high street chains have expressed interest.

Coming from essentially free waste, Kay said both the biodiesel and pellets can be produced at 10% below market trading price. He added: “We see this as the next step in creating a sustainable supply chain. People have concentrated a lot on the first stage of the supply chain, the Fairtrade and Rainforest Alliance movements to ethically source coffee.

“But then as soon as someone drinks it it’s seen as the end of it – we’re saying the next step of sustainability is to close the loop and ethically dispose of it, and creating something really valuable from it.”

Liz Gyekye

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