Half of Germany's electricity will be generated from renewable energy within 10 years - faster than the government's forecast.
The current boom in new installations of wind, solar and other renewable power sources will easily top the official target of 35 per cent by 2022, reaching about 48 per cent by then, said Stephan Kohler, who heads the government-affiliated agency overseeing Germany's electricity grid.
"I think this is a realistic dimension," he said.
"By then we can manage to integrate it in our electricity grid."
He cautioned, however, that his Federal Network Agency's assessment shows that more and swifter investment is needed to upgrade the electricity grid to cope with the influx of unstable and geographically dispersed renewable energies.
One of Germany's challenges in ensuring a steady supply of electricity to the world's fourth-largest economy is that it derives most of its wind power from the country's north, but demand is highest in the strongly industrialised south.
To cope with that, the agency estimates that Germany needs to build another 3,100 miles of high voltage lines.
Germany decided after Japan's 2011 nuclear disaster to speed up phasing out nuclear power, which then accounted for just under a quarter of the country's electricity production, about the same share as in Japan and the US
Renewable energies' share has since risen from 17 per cent to 2 per cent, driven by subsidies and investment incentives that are mostly paid for by a tax on households' electricity bills.
By 2050 Germany, Europe's biggest economy, wants to generate 80 per cent of its electricity from renewable sources.
"Never has an industrialised nation tried to transform its electricity production in such a radical manner as we are currently doing it," Kohler said.