London will be the first of the 16 world cities signed up to the C40/Clinton Climate Initiative to act to reduce CO2 emissions in existing buildings.

Mayor Ken Livingstone is inviting bids to make Greater London Authority (GLA) Group buildings more energy efficient.

This first set of up to 100 buildings to get an energy upgrade will include landmark offices such as Transport for London’s Windsor House headquarters.

The move is the start of a process that will create a framework for the entire public sector. Livingstone also hopes to engage private sector building owners.

A notice in the Official Journal of the European Union seeks expressions of interest for an initial contract. Bidders will be required to provide surveying and auditing services and be able to plan, project manage and implement energy saving measures. They will also have to guarantee to meet energy savings targets.

Livingstone said: “London is leading the way by being the first of the 16 cities signed to the C40/ Clinton Climate Initiative to begin work to cut climate change emissions by making our buildings more energy-efficient.”

The other signatories are Bangkok, Berlin, Chicago, Houston, Johannesburg, Karachi, Melbourne, Mexico City, Mumbai, New York, Rome, Sao Paulo, Seoul, Tokyo and Toronto.

“We have started the tender process for companies to bid for the first part of the work and I hope that this will lead to a boost in London’s green industries,” Livingstone said.

The GLA Group includes 900 buildings occupied by Transport for London, the Metropolitan Police Authority, the London Fire and Emergency Training Planning Authority and the London Development Agency. Energy audits could save up to 50,000 tonnes of carbon emissions a year.