London's first big zero-carbon scheme since BedZED has been given the go-ahead by London mayor Ken Livingstone.
Livingstone is set to announce in his budget, due out on 15 February, £50,000 funding for a feasibility study aimed at identifying a site and a developer.
Darren Johnson, a Green party member of the London Assembly, said the London Development Agency, which is leading the scheme, had already narrowed down the search for a site. He said: "The site will most likely be in east London. This will be a pilot project so there will be particular attention paid to the costs."
The move comes as the mayor faces criticism for failing to implement his own energy strategy.
Despite a policy of seeking an "excellent" BREEAM rating in all new LDA schemes, only 17% of recent projects have achieved this.
Furthermore, the strategy states all bodies within the GLA will power their buildings from renewable energy sources by the end of 2005. But the LDA and the London Fire and Emergency Planning Authority have still not made the switch.
Johnson said: "If the mayor can't persuade his own bodies to take action on climate change, it will be impossible to persuade others."
The GLA was unavailable for comment.