More than 100,000 demonstrators took to the streets in 20 cities across Germany on Saturday to call for a rapid end to nuclear power, even as a government-sponsored national commission is expected to recommend that Berlin abolish nuclear energy within a decade.

The Ethics Commission is set to announce the results of its final report on Germany's energy future, calling for nuclear power to be phased out by 2021.

Chancellor Angela Merkel had tasked the commission with forging a national consensus on how to replace nuclear power with renewable energy in the aftermath of the Fukushima nuclear catastrophe in Japan last March.

The political opposition praised the commission's recommendation while expressing doubt about how Chancellor Merkel's center-right coalition would receive the report.

"I have doubts whether Merkel can successfully implement this position within her coalition," said Thomas Oppermann of the center-left Social Democrats' parliamentary group.

Nationwide protests

In Berlin, at least 20,000 protesters marched from city hall to the headquarters of Merkel's conservative Christian Democrats, where they called for an immediate end to nuclear power.

Merkel may have trouble getting her coalition partners to accept the timetable

Demonstration organizer Uwe Hiksch said an exit from nuclear power within a decade was not acceptable. The environmental organization Friends of the Earth Germany (BUND) also called for a quicker shutdown of the country's nuclear plants.

More than 10,000 protesters took to the streets in North Rhine-Westphalia, Germany's most populous state.

"This is our signal to Chancellor Merkel that the energy turnaround finally has to come," said Tim Petzoldt of the Initiative Anti-Atom Bonn.

Calls for caution

Meanwhile, Economic Minister and Vice Chancellor Philipp Rösler expressed concern that completely abolishing nuclear energy too quickly could lead to electricity blackouts across Germany.

As a precautionary measure, Rösler - member of the liberal Free Democrats - called for some nuclear plants to be left functional as a "cold reserve" in the event Germany needs more energy.

"That would mean that one or two nuclear plants would be left in a cold stand-by mode for a certain period of time and would not be immediately dismantled," he said.

Rainer Brüderle, head of the Free Democrats parliamentary group, called for certain conditions to be met before nuclear energy was phased out. Brüderle said the power grid for renewable energy needed to be expanded.

"If we don't accelerate the expansion of the grid for renewable energy, then we will ultimately fail in the end," he said.

Currently, only four of Germany's 17 nuclear power plants are operational. Chancellor Merkel ordered eight to be shutdown pending review while five more were shutdown for routine maintenance.

On Sunday, Merkel's coalition government will meet to agree on a timetable for the shutdown of Germany's nuclear plants.

Author: Spencer Kimball (Reuters, epd, dapd, KNA, dpa)

Editor: Andreas Illmer