The revered source of fuel for human beings is now set to power some of London’s buses as well. A partnership between Shell; Bio-Bean, the world’s first company to produce biofuels and biochemicals from recycled coffee grounds; and Argent Energy, the UK’s foremost producer of biodiesel, has produced an alternative fuel for London’s buses using coffee grounds.

Londoners consume upward of 20 million cups of coffee per day, which the partnership estimates would be enough to power a third of London’s transport network. To produce the fuel, Bio-Bean obtains the coffee waste from coffee shops and instant coffee factories, and uses its recycling plant to extract an oil from the grounds. The plant can process 50,000 tonnes, or about 55,115.5 U.S. metric tons, of coffee waste annually. Once the oil is extracted, it is blended with diesel to produce a B20 biofuel.

To date, the partnership has produced enough to fuel one bus for one year and is well on its way to producing more. As an added bonus, the fuel works with pre-existing engines, so the buses do not require any modification in order to use it.

The deployment of this new fuel will be another step toward London’s goal of a zero-emission transport system by 2050.