Four fire engines and around 25 firefighters were called to a fire at a power station on Old Woolwich Road in Greenwich.
A gas turbine generator contained in a unit on the ground floor of the two-storey building was destroyed by the fire. Two people left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 1811 and the fire was under control by 2002. Fire crews from Greenwich, East Greenwich and Deptford fire stations were at the scene.
The fire is believed to have been accidental but the cause has been recorded as undetermined.