As we reported Wednesday, Germany plans to shut down its last nuclear power plant in 2022. It's an ambitious timetable. But even more ambitious is its plan to replace that energy with renewable sources, such as wind and solar power. If the plan works, within 40 years Germany will get 80 percent of its power from "renewables."
But there are major challenges.
The blades on a 300 foot tall wind turbine spin over farmland outside the northern German town of BrunsbÃ¼ttel. Hundreds more stand out against the skyline. And more are being built every day, onshore, and in huge wind farms at sea.
Germany is living a wind boom. It's already helped push renewables to 17 percent of the country's total energy supply. And many here hope that's just the beginning.
Jan Espins, head of a renewable energy consortium in nearby Hamburg, said investment in renewables was strong before Germany decided to phase out nuclear power – and it needs to be to be even stronger now.
"We have the official government goal to reach 35 percent by 2020," he said. "And 80 percent by 2050. We need to double it in eight or nine years."
To do that, and to meet its longer-term goals, Germany will have to make tough decisions and costly investments. To start with, Espins said, the government needs to do more to encourage investment in renewables.
He said the country will also have to make big changes in its electricity infrastructure. That is, the cables and towers needed to transport all that new power.
"We have new capacity in the north of Germany and we have our load center in the south," he said. "We need to transport the electricity. And at a certain stage we will definitely need more grid capacity."
It's a matter of feasibility, and money. Beefing up Germany's power grid will cost well over a $100 billion.
But it's also a matter of public acceptance. Werner Beba, a professor at the University of Hamburg who studies renewable energy, said Germans love the idea of renewable energy. What they dislike are things like power lines.
"For example, they are building one strong grid from the North Sea across Germany to bring energy from off shore wind farms to southern Germany. And there are 8,000 — 8,000 lawsuits against that."
There's even resistance to the wind turbines themselves. They're a blight on the landscape, some people say. Others worry that they kill birds. And a growing number of people claim they can make you sick.
Those wind turbines heard wooshing away near the town of BrunsbÃ¼ttel stands about 350 yards from the home of Marco Bernardi and his wife Yutta Reichardt. On a recent day Bernardi pointed to a decibel meter at the turbine.
"We're standing in front of my property with A-rated measures of 48, 45 decibels," he said. "Now we're going to change to C-rated measurement."
Bernardi said C-rated measurements register sounds so low we can't hear them. Set to C, Bernardi's decibel meter spiked.
"We went up to 72, 76 decibels. I think this is evidence that these turbines emit a low frequency sound."
Bernardi and his wife claim those low frequency sound waves have destroyed their health. They blame the turbine for a host of medical problems, from irregular heartbeats to lymphoma.
Most studies of the health impact of wind turbines have found no effects other than occasional stress and anxiety – certainly nothing like cancer.
But Bernardi and Reichardt don't believe those studies. And they've joined with others across Europe to fight the industry. They say they support the decision to shut down nuclear power. But instead of renewables like wind, they want Germany to focus on what they feel could be a safer energy option – new, cleaner coal-fired power plants.
Some new coal plants are in the mix in Germany, like this one being built in Hamburg. Backers of coal say that whatever the benefits or costs of wind and solar, coal offers something that renewables can't: consistency.
Stephan Kleinmeyer, a spokesman for the energy giant, Wattenvall, said that's vital for an industrial country like Germany.
"For the region of Hamburg, we have 12 minutes of power outage each year," he said. "Which is one reason why companies that rely on constant power supply come to Germany. And politicians have to keep this in mind."
But politicians also know that coal power is nearly as controversial as nuclear, even with the latest environmental controls.
So the German government will have to strike a delicate balance between tried and true, but polluting sources like coal and cleaner new ones that have never been used on a massive scale.
Environmentalists say it's a false choice, and that renewable energy can be just as reliable as coal. Kristoph Von Lieven of Greenpeace said the key is that new energy grid we heard about earlier.
"Germany needs smart grids," he said. "Nets of electricity where the possibility of exchange and distribution is much better than nowawdays. If we have this, we don't need big plants, but lots of power plants of different types."
Some experts doubt that smart grids will answer the reliability question. But one thing everyone agrees could help meet Germany's post-nuclear energy challenge is reducing consumption. And on that front Germany is already a leader.
Here in Hamburg one afternoon workers were finishing up a so-called passive-house. There are already about 10,000 of these super-insulated homes in Germany. They consume almost no energy, says architect Kirsten Reumschussel.
"A passive home loses so little heat that it doesn't need active heating," she said. "Most of its warmth comes from the sun, from the body heat of the inhabitants, and from household appliances."
Germany's Green Party says the country could cut energy consumption by 30 percent through passive homes and other simple technologies and changes in behavior.
That would go a long way toward easing Germany's transition away from nuclear power. And, despite the challenges, energy analyst Werner Beba was optimistic the transition will be smooth and relatively quick. He said you only have to look at the booming renewable energy business to see why.
"The average growth per years is 20 percent in employees and in revenue," he said. "That's great."
Great, he said, because one day Germany could become the first industrialized country to rely almost entirely on clean energy.