The Pope has become the latest convert to solar energy and plans to use it to power chunks of the Vatican.
Engineer Pier Carlo Cuscianna said the roof of the Paul VI auditorium will be redone next year, with its cement panels replaced with photovoltaic cells to convert sunlight into electricity.
When the 6,300-seat auditorium is not being used, the electricity will feed into the network providing (other Vatican offices can use the energy.
The Vatican is considering the installation of photovoltaic cells on roofs of other Holy See buildings. The more historic buildings will not be touched.