The south German city of Freiburg is showing the rest of the world how to create a green community from solar power.

Jerome Barrier was visiting from France to glean some town planning tips for back home.

"The nice thing with Freiburg is you find everything here," he said. "You have housing estates, sustainable development housing estates, you have this solar fabric, you have training centres, design centers, research centres, so everything is in the same place so in two days you can see all the technologies and I would say all the tricks that we can implement where we come from.

Barrier and other visitors can see a carbon-neutral, zero-emissions factory powered by a solar-panelled facade and renewable energies such as rapeseed oil. A football stadium powered almost entirely by the sun and wood chips from the surrounding Black Forest.

Or,so-called passive energy houses in the Schlierberg Solar Village that regulate their own temperature through innovative insulation techniques, using 10 per cent of an average home's energy.

Freiburg is actually one of Germany's sunniest cities. Which partly explains partly why they're such pioneers in the field of solar technology.

Homeowners who produce more renewable energy than they consume can sell that on to utility companies at a subsidized rate.

Despite its cloudy skies, Germany is the world's biggest market for solar energy. But strong demand here has led to a shortage of the key solar panel component, silicone.

That means it's more expensive for sunnier parts of the world to install solar technology where it might make more sense. Even Freiburg's mayor agrees photo-voltaic energy from the sun is not necessarily the answer.

"It's a symbol, it's not the big shot, it's a symbol and i think the future of photo-voltaic will be in the less developed countries," the mayor said.

In early June the German government agreed to dramatic cuts in government aid to the solar and wind sectors. A new imperative, besides the high price of oil, to drive innovation and to make existing renewable power generation more efficient.