The Great Stilling: Can modern technology overcome Germany’s throttled wind energy?

The SPD, Greens and FDP have now agreed to formally launch talks about forming the next government coalition in Germany, and they have big ambitions for wind power. In their preliminary plan for government the parties have agreed to designate two percent of Germany’s land mass to wind energy.

This is a lot to digest for an industry that has begun to falter after two decades of growth and technology breakthroughs. Wind power last year generated almost a quarter of the country’s electricity, but no offshore commercial windfarms were built in the past year for the first time in a decade, according to the German Wind Energy Association.

The association puts this down to increasing requirements and less construction space in the crowded North and Baltic seas. “To maintain the technological leadership of Germany… the expansion must be rekindled,” the association says.

“Space is going to be a very sought after commodity,” said Po Wen Cheng, head of wind energy at the Institute of Aircraft Design, Stuttgart University. “The more windfarms we put together, the less they are going to produce per square metre.” While turbine technology has reached maturity, there are still ways to optimise wind parks to generate the most power for the longest amount of time, Cheng said.

For example, engineers in one project are investigating how wind turbines, when bunched together, can avoid the low-speed ‘wake’ from the turbines in front of them. Another project is designing a turbine that can align itself to face changing wind directions. Fraunhofer is developing methods to test turbine blades so manufacturers have a better idea of their long-term effectiveness.

But storing wind power is also a problem, as not all of the electricity generated in the north can reach the energy-hungry south because of an under-resourced energy grid. As the International Energy Agency notes, Germany’s infrastructure is so fractured that northern Germany has at times deliberately stopped producing power from wind to prevent congestion in the few north-south energy connectors.

This is where new hydrogen technology, a recent research priority for Germany, could play a role. The government-funded H2Mare project is experimenting with integrating an electrolyser into a wind turbine to directly generate hydrogen from water using renewable energy. This would ease pressure on the existing electricity grid, and the hydrogen can be stored for later use, said Matthias Müller of Siemens Energy, who coordinates the project.

Electrolyser technology has now reached a point where wind-generated green hydrogen can begin to be used by north German industries in the next decade, Müller said.

The port city of Bremen is also betting on wind power to boost hydrogen’s prospects. The Hydrogen Lab Bremerhaven is assessing how hydrogen produced using electricity generated by wind turbines could soon be used in the local energy grid, to fuel ships and the food industry.

“Normally, it's better to have total electrification,” said Carsten Fichter of the Institute of Wind Energy at the University of Applied Sciences Bremerhaven, who is managing the project. Green hydrogen is particularly suited to industries that still rely on natural gas, such as transport fuel or hydrogen ovens. “These will have the best chance with hydrogen because we have a multifunction fuel,” he said.

Build your own farm

Increasing the amount of energy generated on the north coast is unlikely to square Germany’s power supply circle, since building new high-voltage power lines from north to south is still politically touchy.  

An alternative is for southern Germany to build its own wind farms. Cheng says that although the south has less wind, the new generation of longer turbine blades means modern wind farms can generate far more electricity. The south could benefit from larger, lighter blades that would help its turbines catch up on power output.

Better engineering is needed to install turbines in the south’s hard-to-reach hilly areas, where construction space is limited. Modular blades on smaller trucks can better navigate twisting mountain roads. One German company recently revealed a prototype turbine built with a ‘climbing crane’ that can dramatically reduce the area needed to install turbines.

But any of these engineering feats can get buried in red tape. Alongside federal regulations, wind farm developers must follow unique state regulations in each of Germany’s 16 federal states. For example, in Bavaria wind turbines must keep a distance of at least ten times their height from the closest village.

Wind farm developers also need to bid for tenders to build on the increasingly limited land. Usually experimental wind turbines are excluded from these tenders, but German law says that they must not generate more than six megawatts of power (roughly equivalent to half the power for a Eurostar 20-carriage train).

New turbine technologies are now exceeding that threshold, meaning that if manufacturers want to test their turbines they must place a bid in a commercial tender. At the moment auctions are undersubscribed, so it’s easy to win space for demonstration turbines. But once demand returns to normal that will no longer be the case.

The rule is carried over from earlier legislation, itself based on EU state aid rules. Applying it to modern turbines is “totally ridiculous,” said Mirko Moser Abt, a policy adviser at the German Wind Energy Association, which represents operators in the sector. “The policy environment and the levies and taxes don't really allow wind energy to live up to its full potential,” he said.

Repowering

The rule means that some manufacturers are threatening to move their turbine research out of Germany, to places with more relaxed rules.

Legislation is also standing in the way of ‘repowering’ existing wind farms by discouraging some owners from replacing older turbines that are reaching the end of their life cycle. “The first turbines were placed on the sites with the best wind conditions. Many of these turbines are now 15-20 years old, so they are going to reach their end of life relatively soon,” says Alexander Vandenberghe, Research & Innovation Manager at WindEurope. He says the rule of thumb is that repowering old turbines with just a third of new, more efficient turbines can double the installed capacity and treble the power output of a given site. 

But legislation is preventing this from happening, because some areas are no longer zoned for the wind farms. As a result, some German wind farm owners keep the old turbines in place, running at a fraction of their potential output, until they are allowed to install new turbine technology.

“It’s a little bit like when you’re at the hotel pool; you place your towel there to keep your place,” says Moser-Abt.

Nonetheless, he is optimistic about the next government’s plans. The next legislative term is likely to see the six megawatt threshold for experimental turbines scrapped, meaning more research can be carried out in Germany. And Moser-Abt said if the coalition’s plan to dedicate 2% of German land to wind succeeds, the country will quickly catch up on its climate goals.

But even given that everyone has a common goal, there could still bumps on the way. “You can agree on world peace,” said Moser-Abt. “[It’s] when you ask them how to make it happen where the real debate starts.”