A low-carbon Olympic flame will light up the 2012 Games provided a way can be found for it to be bright enough.
EDF Energy said the low carbon flame will definitely happen
A carbon-neutral flame is difficult to see so Olympic organisers are looking for a suitable bio-fuel.
It is part of many measures announced by London 2012 organisers aimed at making the event the greenest ever.
It includes a carbon footprint study, a sustainable food strategy and a pledge to ensure no waste is sent to landfill during the Games.
An independent sustainability assurance body - the Commission For A Sustainable London 2012 - is being set up to provide independent monitoring of the plans.
The London Organising Committee (LOC) and EDF Energy have begun to search for a suitable bio-fuel for the flame, due to stand outside the stadium in Stratford.
Gareth Wynn, of EDF Energy, said that the low carbon flame "will definitely happen".
One possible answer is a bio gas, perhaps methane, using an organic material such as tree cuttings, he suggested.
Mr Wynn said: "The flame is such an iconic image that we have to get it right."
London 2012 chairman Lord Coe said: "We hope to use the power of the Games to drive change - behaviourally and in the way big events are staged in the future."