"If we want to quickly get out of nuclear power and into renewable energy, we need fossil-fuel power plants. There is no way around," Merkel said in an address to the Bundestag Thursday.
More than a dozen new coal plants already are planned in the next several years, many of them cleaner replacements for obsolete plants, The Washington Post reported.
Merkel pledged that Germany would still meet its carbon-emissions targets while ending nuclear power.
"It's going to be a bit of a make-or-break experiment, which everyone is watching extremely carefully on a global basis," said David Baldock of the Institute for European Environmental Policy in London. "It's quite brave."
Germany now gets a quarter of its electricity from nuclear power plants, more than the United States but far behind France, which relies on nuclear power for almost 80 percent.
This year's disaster at Japan's Fukushima Daiichi nuclear plant, caused by an earthquake and tsunami in March, has energized the powerful anti-nuclear movement. The Green Party recently took over its first state government, Baden-Wuerttemberg.