The move to push people into installing rooftop solar panels has been hugely successful in Germany with citizens encouraged to fit the panels and then sell any surplus power back to the national grid. Generous subsidies from the government has also seen the uptake of solar energey soar.
But Stephan Kohler, an energy adviser to the government, has warned that the green boom could turn into a disaster for Germany's aging power grid.
'The network is facing a congestion due to solar power,' Kohler told the Berliner Zeitung newspaper. 'That's why the expansion of solar power has to be cut back quickly and drastically.' His warning highlights one of the problems with rushing too quickly onto relying on renewable sources to fill any energy shortfall.
Germany this year agreed to reduce subsidies for rooftop panels by 16 percent, which led to a huge take-up of solar power. But the problem with solar power is that it is prone to surging when the sun comes, out, usually around midday. Smaller surges can be dealt with by switching off conventional power plants.
However if the surge is too large than the grid will struggle to cope, even if coal-fired generators are all switched off.
Experts forecast between 8 gigawatts and 10 GW of solar power capacity to be installed this year - the equivalent of roughly 10 large coal-fired power plants. In 2009, only 4 GW were installed.
If the current trends continue, experts expect Germany would have a solar power capacity of nearly 50 GW by 2013.
'That would be a catastrophe for the grids,' Kohler said. He is urging the German government to cap the installation of new solar panels at 1 GW per year.
'Then we could reach the manageable benchmark of 30 GW in 2020,' he said. Many experts believe that the grid needs to be strengthened where solar power could overtake demand in some areas.