Cambridge University says it will cut emissions but some historians are unhappy.
A year-long project to repair the Kings College Chapel roof has been completed, and work has begun to add 438 new solar panels.
Restoration of the Chapel roof had become increasingly urgent once it was discovered the lead roof covering was no longer watertight.
Kings College recognised a "once-in-a-generation opportunity" to both completely restore the roof and install photovoltaic (PV) panels while the necessary infrastructure was in place.
It's understood the panels will meet 100% of the energy needs of the Chapel and will reduce the College's carbon emissions by more than 27 tonnes each year.
However, the scheme has been criticised by some, with Historic England saying it came at "some cost to the beauty of Cambridge's finest building".