(Reuters) – Waste coffee grounds will be used to help fuel some of London’s buses, Royal Dutch Shell (RDSa.L) and clean technology company bio-bean said on Monday.

A new biofuel, which contains part coffee oil, is being added to the London bus fuel supply chain where it can be used without the need for modification, the companies said in a statement.

Bio-bean and partner Argent Energy have so far produced enough coffee oil to power one bus for a year, if used as a pure-blend for the 20 percent bio component and mixed with mineral diesel to form a B20 fuel, they said.

Transport for London has been turning to biofuels to curb carbon emissions, trialling a fuel made with used cooking oil from the catering industry, the transport operator said on its website.

Bio-bean said the average Londoner drinks 2.3 cups of coffee a day, producing over 200,000 tonnes of waste a year. It collects waste grounds from high street chains and factories, which are dried and processed to extract coffee oil.

“It’s a great example of what can be done when we start to reimagine waste as an untapped resource,” bio-bean founder Arthur Kay said.

The coffee fuel technology has been supported by Shell.