Almost a third of London buses will soon be powered by biodiesel made from food industry waste, including cooking oil and tallow from meat processing plants.

Waste-to-energy biodiesel producer Argent Energy has signed a deal with London bus operators Stagecoach and Metroline to supply them with B20 green diesel. This cleaner burning fuel is a blend of diesel and renewable biodiesel from waste products.

Transport for London (TfL) requires biodiesel for London buses to be made from waste, rather than crop-based feedstocks.

By March 2016 almost 3,000 of the city’s 8,900 buses will be powered by the B20 fuel blend, improving air quality and cutting the fleet’s CO2 emissions by 21,000 tonnes each year. More than 640 buses have already been running on the fuel as part of a two-month trial.

This improvement is being introduced with no extra spending and no long delay for the fitting of new kit, said Mike Weston, TfL’s director of buses.

Deputy mayor for environment and energy Matthew Pencharz welcomed the new agreement and said that the biodiesel blend makes use of fuels “that would otherwise be clogging up our drains”.

He added: “This is ongoing progress for running our bus fleets on waste products and cutting CO2. We will continue to work with our industry partners to use more of London’s used cooking oil turned into biodiesel right here in the city, creating green jobs and fuel[ing] self-sufficiency benefits.”