It's sounds like something out of a science fiction movie, but it isn't; the London buses are being powered by coffee.
Bio-bean is a British startup that is now partnered with Shell and Argent Energy to create a bio fuel for London's diesel buses.
CNN reports that bio-bean has "produced 6,000 liters of coffee oil for the pilot project with London's transportation authority -- enough to help power the equivalent of one city bus for a year."
Bio-bean founder Arthur Kay says in a statement: "It's a great example of what can be done when we start to reimagine waste as an untapped resource."
How does it work?
Bio-bean goes round to cafes and restaurants collecting used coffee grounds to recycle. The coffee waste is dried and coffee oil extracted.
That oil is then mixed with other fuels and the bio fuel called B20 is created and that is what powers the diesel buses.
The company estimates that Britain produces 500,000 tonnes of coffee grounds a year.
If not re-purposed the coffee waste is discarded in landfills which pose an environmental hazard because the coffee grounds emit harmful greenhouse gases.
The project is in it's infancy and there is no formal agreement in place with the British transport authorities but the company is hopeful this is the start of a long term business relationship.