One of the oldest operational power stations in the world is set to have a new lease of life generating low carbon power for the Tube network.
Plans to revamp the 1906 Greenwich Power Station, in south-east London, have been announced by the Mayor of London, Boris Johnson.
The transformed power station will also provide heat for local homes and buildings.
Six new gas engines will be installed in the building's old turbine hall.
'Back to full use'
Mr Johnson said: "With cleaner, more efficient and environmentally friendly new systems, Greenwich Power Station will be brought back up to full use, and go on to perform the function it was originally created for well into the 21st Century.
"This important investment in London's growing low carbon technology sector will not only help power our Tube network, but will also reduce pressure on the National Grid, cut utility bills for local residents, and reduce air pollution from boilers."
Installation of the new engines will be staggered over the next 20 years to match the development of the heat network.
Preparatory work to install the first two engines will begin in April, and they are expected to be running by 2017.
Greenwich Power Station was built to generate steam power for London's former Tram network.
From 1968-1972 gas turbines replaced steam power to supplement output from London Underground's (LU) Lots Road Power Station during peak times and as a standby supply.
When London Underground shut Lots Road and switched to the National Grid for power supplies in 1998 Greenwich became the provider of London Underground's Central Emergency Power Supply.
Mike Brown, managing director of London Underground, said: "By using lower carbon energy we will be able to minimise emissions further and bear down on the operating costs of the Tube."