The Vatican will start using some solar energy, Forbes reports.

The roof of the Paul VI , 6,300-seat auditorium will be redone next year, with its cement panels replaced with photovoltaic cells to convert sunlight into electricity.

The cells will produce enough electricity to light, heat or cool the building. Excess energy will feed into the the Vatican’s network.

The Vatican is considering the installation of solar power on roofs of other buildings, although centuries-old landmarks like St. Peter’s Basilica won’t be touched.