Why wind power and photovoltaics are essential

It’s true, we have fewer discussions there than we do on land. And the wind turbines in the North Sea produce almost twice as much electricity as the ones on land. The UK could cover all of its energy needs with offshore electricity. But from an international perspective, it’s an exception. In general, we can’t use offshore wind turbines to compensate for the turbines that we need but prevent being build on land. Besides, offshore wind energy has to compete with solar energy that is produced on land. If wind energy costs twice as much as solar, it will have only moderate success.

This technology isn’t new, and after all these decades it still hasn’t caught on. Their efficiency is lower and their mechanical stress is higher. On top of that, most of today’s vertical-axis turbines are relatively small. There would probably also be resistance to a land-based five-megawatt wind turbine of this type.

The concrete foundations, the tower, and the generator can be recycled well. The challenge is the rotor blades, which are often made of composite materials. Ideally, in the future the producers of these components should stop using petroleum-based plastics—and, as with almost all other products, here too we have to become part of the circular economy. However, engineers will certainly find solutions for this problem.

Norway is the leader in the field of electric mobility, France will soon no longer permit any combustion-engine vehicles to enter Paris, and Denmark is doing a great deal in terms of wind energy. But no country is perfect. In the climate protection ranking of Germanwatch—where Germany is in the middle range, incidentally—the first three places are vacant, because no country is prepared to implement adequate measures. And there are also states that have no great climate-related ambitions, yet can demonstrate successful progress toward the energy transition.

Take Texas. It’s the US state that is doing the most to promote wind energy. It’s an oil state that has been governed by the Republicans since way back! But Texans have realized that wind energy means big business. For them, climate protection is only secondary.

The mindset of many companies has completely changed in recent years. They are trying to establish environmental standards, and they’ve realized that they can do good business in this new world. I couldn’t believe my eyes when the Federation of German Industries criticized the results of the climate conference in Glasgow as being inadequate and said it had wished for more. I’m glad that companies are trying to structure the necessary transformation in positive ways. Many companies have understood that an industrialized country such as Germany can only stay big and strong thanks to new technologies like these.

Absolutely not. After all, coal is certainly not cheap, especially by comparison with solar energy. In sunny countries, a kilowatt-hour of solar power costs less than two cents. For that amount of money I can’t even buy the necessary coal on the world market. Of course the companies operating old written-off power plants have an advantage. However, if we’re talking about greenfield sites, solar power plants are more economical, even in countries such as India. A very likely scenario is that energy-intensive sectors will migrate to countries where solar and wind energy can be generated cheaply. Thirty years from now, will Germany still have the same steel mills it has today? I don’t think so.

After all, the right question is “Which is cheaper? Bringing green hydrogen to Europe, or taking the steel mill or at least the energy-intensive parts of it to Morocco?” I would choose the second alternative. Of course that would mean losing jobs in traditional sectors here in Germany. But on the other hand, so many jobs are being created by the energy transition that we should instead be thinking about where we’ll find the workers we need.

That’s absolutely right, and it’s also a question of costs. If 70 percent of the product costs are due to energy, you’ll have to think about moving your production plant. How­ever, if most of the costs are due to know-how, production will continue to be located in Germany. And for that we will also need hydrogen, that’s absolutely clear.

China committed itself to technologies such as solar and wind energy early on, and thus it helped to cause the drastic drop in prices. Without China, photovoltaics would probably be about three times more expensive on the world market. This effect is not so great in the case of wind turbines, because they are not as easy to transport. A rotor blade doesn’t fit into a Euro container. Because transportation costs tend to increase, in the future it won’t pay off to produce everything in China.

Yes, this expansion is impressive. However, China’s hunger for energy is also very huge. As a result, the expansion is insufficient to roll back the use of coal. The Chinese would have to actually double their ambitions once again.

The costs of wind power will also continue to decrease, just because of economies of scale: If I build 20,000 wind turbines instead of 1,000, I can manufacture each one of them more cheaply. However, in the short run prices could also rise, because the demand is rising quickly at the moment and it takes a while for production to catch up. I no longer expect the prices of photovoltaic systems to decrease significantly in the years ahead, largely because of the higher labor costs for their installation.

Wind energy is close to its physical limits. In theory, we can reach an efficiency of almost 60 percent, and good wind turbines already reach more than 50 percent today. For photovoltaics the theoretical efficiency is more than 80 percent, but in series production we’ve only reached 20 percent. However, we’re basically facing the problem that photovoltaic systems hardly produce any electricity in the winter, whereas wind turbines do. That’s why there will always be a market for wind energy.

Well, if people believe that our current energy supply is invulnerable, we have to disabuse them of this idea. If two or three major power plants were to break down simultaneously, we would have an extensive blackout today. By contrast, renewable energies operate in a more distributed fashion. If you were to cut down three wind turbines, nothing would happen. Besides, some of these assumptions are quite far-fetched. Of course if everyone recharges his or her electric car at the same time, things will go dark. But something like that will never happen.

That’s right. But I’m not too worried that we’ll never solve this problem. The electric cars that were registered last year in Germany alone have a storage capacity via their batteries that is bigger than the largest German pumped-storage power plant.

Battery technology is roughly at the same point today as photovoltaics were ten or 15 years ago. In the case of lithium batteries in particular, automation and rationalization will lower the costs in the future.

I own shares in a wind farm, because small wind turbines are not practical. In the case of solar panels, it doesn’t matter whether I set them up on my roof or they are in a field in Brandenburg—they always produce the same amount of energy per square meter. That’s not the case with a wind turbine. The wind becomes much stronger as you go higher. A wind turbine on your own roof wouldn’t produce very much power. Besides, you might get into trouble with your neighbor complaining that the thing makes a lot of noise.

Photos: Silke Reents (2), action press, picture alliance / AP images, ddp images