Hanno Renn, a Freiburg taxi driver, invested in a communal solar electricity system on a building in the German town in 1993. "Everyone laughed and said I was wasting my money," he says.

But now he has paid off his investment and earns a regular income from the electrical company for the power he generates. "I have had the last laugh," he grins.

Mr Renn is part of a revolution in renewable energy that is sweeping Germany and bringing citizens of every kind into the fight against global warming.

While a new report from the Centre for Alternative Technology says Britain could, with sufficient will and effort, go zero carbon in only 20 years, Germany's figures put the British government's claims to be leading the world on climate change into perspective.

Germany has 200 times as much solar energy as Britain. It generates 12% of its electricity from various renewables, compared with 4.6% in Britain. It has created a quarter of a million jobs in renewables - a number that is growing fast. Britain has only 25,000, a number that represents the amount of jobs created in the industry in Germany in the past year alone.

Freiburg, a town of 200,000 people in the Black Forest, has almost as much solar photovoltaic (PV) power as the whole of Britain. Dr Dieter Wörner, director of Freiburg's environmental protection agency, admits that such is the competition among German towns that Ulm has just overtaken Freiburg as solar capital of the world.