It is set to become a "state of the art" sixth form centre.
Ely College, on Downham Road, is part of the Meridian Trust group of academies.
In the application that was submitted to East Cambridgeshire District Council, the academy trust said the current sixth form provision was unsafe and unsuitable and that a new facility was needed.
The building is now due to be refurbished and the exterior re-clad.
It will be made net zero with solar panels put on the roof, and an air source heat pump installed.
The district council said it would be a significant enhancement to the existing tower and surrounding area.
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