How much power
The panels on the first six schools produced 412 megawatt hours between April and September, a little more than the planners expected. Over a full year, the 23 schools together should produce around 1,900 megawatt hours.
Lessons on the roof
Every system has a display in the entrance hall that shows what the roof is producing at that moment. Two secondary schools use the live data in physics and maths lessons, and pupils at Gesamtschule Nord built their own weather station next to the panels.
Why not every roof
Some roofs are too weak for the extra weight, others are due for renovation within the next ten years. The city wants to fit panels there when the roofs are replaced, so they do not have to be taken down again.