Elmlea Junior School in Westbury-on-Trym is the first in the city to benefit from free solar panels worth £20,000.

They were switched on yesterday at a ceremony involving officials of The Co-operative, which has funded the panels through its Green Energy scheme.

The 24 photovoltaic panels should generate about 3,300 kilowatt hours of electricity each year – enough to power a school computer for 33,000 hours or to make 180,000 cups of tea for thirsty teachers – saving about two tonnes of carbon dioxide.

Pupils can keep track of how much renewable energy the panels are generating and the amount of carbon dioxide they have saved by checking a monitor in the school building.

Year 4 teacher and sustainability leader Rebecca Walker said: "We are proud to be among the schools leading the way on renewable energy. We are already working hard to reduce the school's carbon footprint and switching on these rooftop solar panels will instantly boost our efforts while sending out a strong message about our commitment to helping the environment."

Year 6 pupil Lucy Waldren, 11, said: "The solar panels are a great way to make energy and the whole school is excited to be involved in this scheme."

John Tymon, manager of The Co-operative food store in Westbury-on-Trym, said: "This clean, silent technology will help educate Elmlea Junior School's pupils about green energy as well as reducing the school's reliance on fossil fuels.

"We hope the switch-on of these rooftop solar panels will give the whole community a jolt by sending out a strong message about the urgent need to do what we can to tackle climate change."