Buses powered entirely by biofuel are taking to the streets of Nottingham as part of a major trial.
The Ecolink will take the number 30 route between Wollaton and the city centre using three vehicles running on waste wood-sourced ethanol.
The 18 month trial will gauge if buses using this type of fuel are viable.
Ethanol fuel is thought to reduce CO2 emissions by 30 tonnes per bus per year - roughly 90% - and also cut levels of nitrous oxide and particulate matter.
A spokesman for the city council said: "During the trial period, the costs of importing ethanol from Sweden will be assessed against locally-grown sugar beet and wood, to help determine whether in future, the ethanol could be sourced closer to Nottingham.
"This follows the recent opening of an ethanol production plant by British Sugar at Whissington in Norfolk, which uses locally produced excess sugar beet to generate the fuel."
The trial is being conducted in partnership with Nottingham City Transport and has been part funded by the East Midlands Development Agency.