The Prince of Wales has won permission to install 32 solar panels on the roof of Clarence House, his listed London residence. The photovaltic panels are expected to produce 4,000 kilowatt hours of electricity. It is the latest in a series of efforts to make his household “carbon negative”—meaning it generates more energy than it uses. Already the home, formerly occupied by his grandmother Queen Elizabeth the Queen Mother, has high efficiency boilers. He’s even taken his carbon campaign into the garage. His Jaguar and Land Rover run on biodiesel derived from used cooking oil while his classic Aston Martin runs on bioethanol fuel made from surplus British wine. There was no objection to his latest green scheme since the roof is surrounded by high parapets which will make the panels invisible from the ground.