On Monday, Greenpeace activists amassed before the Kruemmel nuclear power plant near Hamburg to protest yet another incident at the Vattenfall Europe-run facility.
It shut down automatically on Saturday after a transformer short-circuited. Kruemmel was reopened only last month after a two-year closure because of a fire in 2007. The planned restart had been accompanied by several minor issues that culminated in the shutdown over the weekend.
Environment Minister Sigmar Gabriel on Sunday ordered that all German nuclear power plants undergo a check for the safety of their electrical systems as a consequence of the Kruemmel blackout.
He also said he wants to shut down aging German nuclear power plants quicker than planned. The German government in 1998 decided to mothball all of the country's 17 remaining nuclear reactors -- which in 2007 accounted for 21 percent of the power mix -- by 2021.
Gabriel is one of the main opponents of nuclear energy in Germany. But he has powerful foes: Chancellor Angela Merkel is lobbying for a more relaxed phase-out with extended running times for Germany's most modern plants.
Gabriel made it clear that his Social Democrats will campaign against nuclear energy in the upcoming national elections this fall.
"On Sept. 27, Germans will decide whether this reactor and several others run for longer, as Chancellor Merkel has proposed, or whether we can finally switch off eight of these problematic reactors," Gabriel told public broadcaster ARD.
Merkel's Conservatives do not advocate the construction of new nuclear power plants but lobby for nuclear to remain in the mix beyond 2021 as a bridging technology until renewable energy sources can satisfy most of the demand.
Kruemmel, built in 1984, is scheduled to close in 2018. Its operator Vattenfall has pledged to investigate the incident.
Germany is one of the few countries in Europe that hasn't joined the recent nuclear revival.
In February, Sweden reversed a decision from 1980 to phase out the country's nuclear reactors.
Over the past few years, Italy, the Netherlands, Belgium, Switzerland and Britain have scrapped phase-outs, extended running times of their plants or even decided to build new ones. Eighty percent of France's electricity is produced in nuclear plants, and Finland is currently building what will be the world's largest nuclear power plant.