Bonn, Germany—On the afternoon of April 29, 1986, West Germany's Interior Minister Friedrich Zimmermann walked out of a meeting with the Commission on Radiological Protection and spoke to a TV reporter.
"There is no danger," Zimmermann assured millions of anxious viewers. "Chernobyl is 2,000 kilometers away."
Zimmermann's words carried authority—and not just because of his high office. He looked authoritative, dressed in a dark gray suit, white shirt, matching dark tie, and steel-framed aviator glasses on his plump face. He also spoke with the cold command of a lawyer, which he had been before entering politics.
The only element out of place in his reassuring performance that day was a large oil painting on the wall behind him. It depicted storm clouds gathering above churning seas and its omen of dread proved to be the most accurate part of the interview. Chernobyl, in Soviet Ukraine, was 300 miles closer than Zimmermann had said. Even as he spoke, a radioactive cloud released by the worst nuclear power disaster in history was over East Germany and drifting west.
Like all revolutions, the German Energiewende was set in motion by many factors and its course altered by a multitude of events and actors along the way. A few key moments stand out, however, and the Chernobyl catastrophe is one of them. To fully understand the Energiewende, and to anticipate its future twists and turns, it's essential to understand the role Chernobyl played in shaping the German public's view of nuclear power.
This is Chapter 4 of a six-part series on Germany's remarkable clean break with coal, oil and nuclear energy. Click to read Chapter 1 , Chapter 2 , Chapter 3 , Chapter 5  and Chapter 6 . Or read it all now  as a Kindle Single ebook on Amazon for 99 cents.
Take Marianne Störmer, for example, my seatmate on a trip crossing a swath of northern Germany. She was a young schoolteacher in Hamburg when the nuclear power plant at Chernobyl exploded and burned out of control for 10 days, and she vividly recalled that time of angst. "A lot of radiation came over here so you had to be very careful about what you ate," she said. "Milk was contaminated. I had always gathered mushrooms in the forest, but we were told not to do that anymore."
Now in her mid-fifties, Störmer describes herself as a "typical Bürgher"—German shorthand for a cliché of middle-class and middle-of-the-road sensibilities from an earlier era. She looked the part: conservatively dressed with medium-length brown hair, plain-rimmed glasses and a stout build. A physics teacher, she had admired the engineering and scientific brilliance that made it possible to harness energy from splitting atoms. She had believed in nuclear power—until Chernobyl.
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The worst part, she said, was the effect on her 11-, 12- and 13-year-old students. "They were so frightened. So were the parents. They asked me: Should the children play outside? Should they not?"
Störmer gazed out the window and looked at the passing fields. Then she turned back and shook her head in disgust. "Nuclear," she said deliberately, "is a very ugly sort of energy."
A group of German farmers reached that conclusion a decade before Störmer did. In 1975, the conservative residents of southern Germany's grape-growing region occupied the site of a planned nuclear power station, forcing its cancellation. A decade later, when they were ordered to destroy their crops because of radioactive fallout from Chernobyl, they believed their nuclear doubts had been confirmed.
As time passed and memories of Chernobyl faded, however, the German public's wider outcry against nuclear power receded. Through the mid-1990s, the nuclear industry and the ruling conservative government fought nuclear opponents to a standoff. No new plants were built, but no existing facilities were closed. In 2000, a new government passed the comprehensive legislation that became the foundation for the Energiewende, and it included the gradual phase out of nuclear power. But that part of the law was overturned a decade later by the center-right coalition led by the current chancellor, Angela Merkel, who also extended the life of aging nuclear plants by up to 14 years.
Merkel's decision triggered Germany's largest antinuclear protests since Chernobyl. But still, the public remained divided on the issue and the fate of nuclear power remained up in the air. Until Fukushima.
On March 11, 2011, an earthquake followed by a tsunami struck central Japan's west coast. The massive wave swamped the six nuclear reactors at the Fukushima Daiichi power plant, triggering three core meltdowns. Germany's long-simmering unease about nuclear power bubbled to the surface and exploded. Antinuclear demonstrators again took to the streets by the tens of thousands, chanting, "Shut them down!"
Less than a week into the Fukushima crisis, Merkel stunned the nation by withdrawing the licensing extensions and temporarily closing seven of Germany's oldest nuclear plants. The restart of an eighth plant, which was offline for refueling, was delayed.
But the real bombshell was still to come.
On May 30, Merkel held a press conference in the Chancellery. Flanked by members of her cabinet and wearing one of her trademark red power jackets, she announced that she was making the temporary closures permanent. What's more, she continued, the most industrialized nation in Europe, and the world's fourth-largest economy, would permanently close all nine of its remaining nuclear power plants by 2022.
Merkel, whose support for the Energiewende had always been tepid, had suddenly pinned Germany's future entirely on renewable energy. It was, wrote one journalist, "as if the pope were suddenly advocating the use of birth control pills."
Merkel had been a prominent researcher in quantum chemistry before entering politics and was well aware of the enormity of the task that lay ahead. But, she told the assembled reporters, this was a historic opportunity for Germany to step forward on the world stage: "We believe that we can show those countries who decide to abandon nuclear power—or not to start using it—how it is possible to achieve growth, creating jobs and economic prosperity while shifting the energy supply toward renewable energies."
The nuclear industry and its supporters pounced on Merkel's decision. They predicted blackouts on a scale Germany hadn't experienced since World War II and skyrocketing electricity prices that would wreck the nation's heavy manufacturing sector, the bedrock of the German economy. They warned that Germany would cease to be an energy exporter and be forced to import electricity from, of all places, French nuclear power plants. Utilities would have to burn more coal to make up for the lost nuclear power, they said, pumping huge amounts of greenhouse gases into the atmosphere. The British weekly The Economist branded Merkel's action "a lunatic gamble."
More than a year and a half later, however, those dire predictions haven't materialized.
There have been no blackouts since Merkel's announcement. On the contrary, Germany's grid, which was already the most reliable in Europe, experienced a total of just 15 minutes and 31 seconds of brownouts in 2011, an improvement over 2010. (The comparable figure for the United States is measured in hours.) The wholesale price of electricity has gone down, not up. The electricity-intensive German manufacturing sector is still thriving. And Germany finished 2011 as a net exporter of energy, while also cutting greenhouse gas emissions by 2 percent.
How did the critics get it so wrong? According to many German energy experts, the naysayers couldn't envision how the new energy economy would work. Rainer Baake, who brokered the original plan to phase out nuclear, said the critics didn't understand that while a single source of renewable energy can't match the constant power of a coal or nuclear plant, a mix of renewable sources can achieve a similar result. For example, solar power produces a predictable range of energy during the day, while winds blow primarily at night. Getting the mix right isn't easy. But so far, Baake argued, Germany's experience suggests that it is possible.
Even some Energiewende supporters, however, criticized Merkel's decision to immediately close several of the nuclear plants. They felt the closures should have been phased out gradually, as the 2000 legislation would have done.
Some analysts suggested that Germany's carbon emissions—which declined by 2 percent in 2011—could have dropped even further if Merkel hadn't acted so precipitously. Even with the Merkel shutdown, however, Germany's old coal plants are being decommissioned faster than new ones—which were ordered years before the Fukushima disaster—are coming online.
Still, more needs to be done to make a smooth transition to a renewable energy economy. The antiquated power system must become more flexible and nimble, able to respond quickly to demand, something the old system wasn't designed to do, Rainer Baake stressed. For all practical purposes, coal and nuclear power have only two settings: off and on. Supporters of the Energiewende argue that this limitation is another reason to stop using coal and nuclear. "The Big Four were right about one thing," Baake admitted. "You have to choose between the old system and the new one. And we have chosen renewables."
In the United States, experts in the fight against climate change are divided on whether or not Germany should have excluded nuclear on its path to a renewable energy future. Author and activist Bill McKibben, who has written about the issue for two decades, believe Germany took the right path. Leaving aside all of the other well-known problems of nuclear power (waste disposal, vulnerability to terrorist attacks, catastrophic meltdowns), McKibben argues that nuclear is simply too expensive to provide more than a small share of the world's energy needs.
"Nuclear plants are frightening," McKibben wrote in his 2010 book, Eaarth, "in part because new ones spill so much red ink."
McKibben's friend and colleague, James Hansen, believes just as emphatically that climate change can't be defeated without greatly expanding nuclear power. In his book, Storms of My Grandchildren, NASA's chief climatologist wrote, "for the foreseeable future, renewable energies will not be a sufficient source of electric power."
The Intergovernmental Panel on Climate Change (IPCC), the preeminent international scientific body on climate change, is more sanguine about renewable energy. In its authoritative Special Report on Renewable Energy Source and Climate Change Mitigation, IPCC scientists concluded in 2011 that, "close to 80 percent of the world's energy supply could be met by renewables," by 2050, while cutting greenhouse gas emissions by a third.
Dr. Susanne Kadner, a researcher at the Potsdam Institute for Climate Impact Research, was a key author of the IPCC report. In April, I met Kadner at Café Einstein, a coffee house favored by Berlin's cultural and political elite. Located on Berlin's grand Unter den Linden Boulevard, halfway between the Brandenburg Gate and Humboldt University (where Albert Einstein and 28 other Nobel Prize recipients taught) the café is a place to see and be seen. The real joy of the place for her, Kadner said cheerily as we settled into our table in the large and bright back room, is that "you can read your newspaper and have coffee and stay for hours and hours."
In fact, we talked for a good hour and a half, with only hot drinks and a single croissant (mine), without waiters hovering and pointedly looking at their watches.
Although the IPCC's renewables report broke ground in several areas, Kadner seemed especially proud of one achievement—a comprehensive "lifecycle analysis" establishing how much CO2 each energy source produces from manufacturing to disposal. Using the largest data set ever compiled, researchers determined that, compared to fossil fuels, renewables sources such as wind and solar power released 10 to 100 times less CO2 per unit of energy.
In practical terms, Kadner said, "What we found was that if you want to mitigate climate change, first, renewable energies can play a role. And second, they have to play a role."
Kadner and her colleagues calculated that of the 300 gigawatts of new electrical generating capacity built throughout the world between 2008 and 2009, 140 gigawatts—nearly half the total—came from renewables. (An average size nuclear reactor produces one gigawatt of electricity)
Even the Energiewende's most ardent supporters admit that, for all its progress, it must still clear some rather tall hurdles. In the short run, Baake said, Germany needs to build more peaking plants—natural gas turbines that ramp up and down quickly to smooth out the intermittent power of renewables. The electrical grid also needs to be expanded (an expensive proposition) and connected to a wider European system (an expensive and politically challenging proposition). In the long term, viable ways must be found to store surplus wind and solar energy.
Baake is confident that, in time, each of these obstacles will be surmounted. After rattling off that daunting list of challenges, he said something that reminded me of my conversation with Hans-Josef Fell, the member of parliament who created the framework for the Energiewende. When I asked Fell about the storage problem, he responded immediately, "It is not a problem. It is a task."
Now it was Baake's turn to demonstrate the pragmatic optimism that powers the Energiewende.
"The tasks ahead are solvable," he said. "Now we have to tackle them."
Chapter 1 
Chapter 2 
Chapter 3 
Chapter 5 
Chapter 6 
Funding for Clean Break was provided by the Heinrich Böll Foundation, through a Climate Media Fellowship, and by the Rockefeller Brothers Fund.