The ceremony was performed by Climate Change Minister Greg Barker, who joined hospital staff and partners involved in the project on a tour of the new facilities.
The new plant replaces the hospitals’ 44-year-old boilers in its continuing efforts to reduce carbon emissions by 10 per cent this year.
The new system converts waste heat from electricity production to heat hospital buildings and produce steam and hot water.
Funded by the hospital and the Department of Health, it is hoped that the centre will also contribute to savings of up to £450,000 per year.
The plant also enables the Trust to sell surplus power back to the National Grid and invest the proceeds into patient care.
Mr Barker said: “I am a big supporter of combined heat and power so I am delighted to be officially switching on the plant at King’s College Hospital in London.
“CHP units are highly efficient at generating energy, which means lower fuel bills and a reduction in carbon emissions.
“This not only sets a great example for the public sector in tackling its carbon footprint, but it also means the money the hospital saves on its heating bill can be ploughed back to the front line.”
Mr Barker spent the morning at King’s and also unveiled a plaque to commemorate the occasion.