The shutdown of the reactors Emsland, Neckarwestheim II and Isar II, agreed to more than a decade ago, was being closely watched abroad.

Other industrialised countries, such as the United States, Japan, China, France and Britain, are counting on nuclear energy to replace planet-warming fossil fuels. Germany's decision to stop using both has been met with some scepticism, as well as unsuccessful last-minute calls to halt the shutdown.

Decades of anti-nuclear protests in Germany, stoked by disasters at Three Mile Island, Chernobyl and Fukushima, put pressure on successive governments to end the use of a technology that critics argue is unsafe and unsustainable.

Environmental groups celebrate

Environmental groups planned to mark the day with celebrations outside the three reactors and rallies in major cities, including Berlin. Small, closed-door ceremonies inside the plants were also organised.

Defenders of atomic energy say fossil fuels should be phased out first as part of global efforts to curb climate change, arguing that nuclear power produces far fewer greenhouse gas emissions and is safe if properly managed.

As energy prices spiked last year due to the war in Ukraine, some members of German Chancellor Olaf Scholz's government got cold feet about closing the nuclear plants as planned on December 31, 2022. In a compromise, Scholz agreed to a one-time extension of the deadline but insisted that the final countdown would happen on April 15.

Still, Bavaria's conservative governor, Markus Soeder, who backed the original deadline set in 2011 when Chancellor Angela Merkel was Germany's leader, this week called the shutdown “an absolutely mistaken decision.”

“While many countries in the world are even expanding nuclear power, Germany is doing the opposite,” Soeder said. “We need every possible form of energy. Otherwise, we risk higher electricity prices and businesses moving away.”

Advocates of nuclear power worldwide have slammed the German shutdown, aware that the action by Europe’s biggest economy could deal a blow to a technology they tout as a clean and reliable alternative to fossil fuels.

Short-term return to coal

The German government has acknowledged that, in the short term, the country will have to rely more heavily on polluting coal and natural gas to meet its energy needs, even as it takes steps to massively ramp up electricity production from solar and wind. Germany aims to be carbon neutral by 2045.

But officials such as Environment Minister Steffi Lemke say the idea of a nuclear renaissance is a myth, citing data showing that atomic energy's share of global electricity production is shrinking.

At a recent news conference in Berlin, Lemke noted that building new nuclear plants in Europe, such as Hinkley Point C in Britain, has faced significant delays and cost overruns. Funds spent on maintaining ageing reactors or building new ones would be better spent on installing cheap renewables, she argued.

The northwestern town of Lingen, home to the Emsland plant, plans to become a hub for hydrogen production using cheap electricity generated from North Sea wind farms, Mayor Dieter Krone said.

The power plant's operator, RWE, has made clear that it is committed to the shutdown. The company still runs some of Europe's dirtiest coal-fired power plants. It recently pushed through the destruction of a village for a mine expansion as part of a plan to increase short-term production before ending coal use by 2030.

Dismantling will be costly

Many of Germany's nuclear power plants will still be undergoing costly dismantling by then. The question of what to do with highly radioactive material accumulated in the 62 years since the country's first reactor started operating remains unsolved. Efforts to find a final home for hundreds of containers of toxic waste have faced fierce resistance from local groups and officials, including Soeder, the Bavarian governor.

“Nuclear power supplied electricity for three generations, but its legacy remains dangerous for 30,000 generations," said Lemke, who also pointed to previously unconsidered risks such as the targeting of civilian atomic facilities during conflicts.

Finding a place to safely store spent nuclear fuel is a problem that other nations using the technology face, including the United States. Still, US Energy Secretary Jennifer Granholm has said that nuclear power will “play a critical role in America’s clean energy future.” This week, she welcomed Japan's decision to restart many of its reactors.

With a national debate raging again in Germany about whether the nuclear shutdown is really a good idea, the top official in charge of nuclear safety at the Environment Ministry, Gerrit Niehaus, was asked by a reporter to sum up in a single sentence what lessons should be learned from the country's brief atomic era.

“You need to think things through to the end,” Niehaus said.