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.”