New buildings in London will have to meet revised green guidelines under proposals designed to help combat climate change.
Mayor Ken Livingstone said the changes to the London Plan will introduce radical measures and targets to cut greenhouse gas emissions.
The building industry has said the move is "overly prescriptive".
The document Draft Further Alterations to the London Plan will be published for public consultation in the autumn.
Among the proposals outlined by the mayor on Tuesday, new buildings must generate 20% of their own electricity.
The mayor said: "The new policies... set tough but deliverable targets for reducing our carbon emissions.
"We must move our cities away from relying on inefficient centralised heat and power generation, and stop constructing buildings that waste heat and electricity.
"In London we want to see the widespread use of decentralised energy, the highest standards of green building design and renewable energy incorporated wherever we can."