London's latest bus garages - both using environmentally-friendly solar power - will be opened by London mayor Ken Livingstone on Thursday.
The two buildings are inline with the mayor's greener energy plans
The refurbished Walworth Bus Garage, which has served the capital for 100 years, now has 744 solar panels on the roof helping power the National Grid.
Vauxhall Cross Interchange, which uses ways of drawing power from daylight, will also be unveiled by the mayor.
His energy strategy calls for all new major buildings to have solar power.
The mayor has said solar power "is in keeping with my goals to make London a sustainable city".
The mayor is due to open the newly refurbished Walworth garage at 1100 GMT.
The Vauxhall Cross Interchange building uses photovoltaic technology which will draw 30% of its energy needs from daylight.
It is enough to power eight three-bedroom homes for a year, Transport for London has said.
The new building will serve 45,000 passengers a day on 12 bus routes.
"These two new buildings are important additions to London's improving bus network, helping to make buses even more reliable and accessible for passengers," Mr Livingstone said.
Transport for London's surface transport managing director Peter Hendy said: "London's bus network is undergoing a revolution.
"The addition of a brand new interchange at Vauxhall Cross and a newly refurbished garage at Walworth gives us even more scope to further increase the reliability of the network."