London has found an innovative way to make its iconic red buses greener—by running them on fuel made from coffee waste. The project, developed by the clean technology company Bio-bean in partnership with Shell and Argent Energy, transforms used coffee grounds into a sustainable biofuel that can power public transport without the need for engine modifications.

Every year, the United Kingdom produces more than 200,000 tons of coffee waste, most of which ends up in landfills. There, decomposing grounds release methane, a greenhouse gas far more potent than carbon dioxide. Instead of letting this resource go to waste, Bio-bean devised a process to dry the spent coffee, extract the natural oils inside, and blend them with diesel to create B20 biofuel—a mixture containing 20% coffee oil.

In its first trial, the company produced about 6,000 liters of coffee oil, enough to power a London bus for an entire year. While that number may seem small compared to the city’s massive fleet, the project highlights the enormous potential of waste-to-energy solutions.

Arthur Kay, the founder of Bio-bean, described the initiative as “a great example of what can be done when we start to reimagine waste as an untapped resource.” His team believes that if scaled up, coffee-powered biofuel could become a regular part of the city’s clean energy strategy.

The environmental benefits are clear. According to researchers, buses running on the coffee blend emit fewer carbon emissions compared to traditional fossil fuels. At the same time, the initiative reduces landfill waste, prevents methane release, and supports the idea of a circular economy—where everyday waste is recycled back into useful products.

London’s trial is also symbolic. Coffee is one of the most widely consumed drinks in the city, with millions of cups brewed every day. By turning something as ordinary as spent coffee grounds into bus fuel, the project connects daily habits with broader climate goals.

Challenges remain, particularly in scaling up production and ensuring cost efficiency. Collecting, drying, and processing coffee waste requires significant investment, and the supply chain must remain consistent to meet the energy demands of a large urban transport system. Still, the early results have sparked optimism.

As London continues to explore cleaner ways to keep its buses moving, the coffee experiment stands out as both imaginative and practical. It demonstrates that sustainability doesn’t always require futuristic technology—sometimes, it can start with the simple act of finishing your morning coffee.