The conversation was moderated by WOLFGANG HESS
A few years ago, German wind turbine manufacturers set the tone; today it is mainly companies from China. How will this continue, Prof. Wenske?
Germany still plays in the top league when it comes to mechanical engineering and gear construction as well as the production of large-scale bearings, among other things. When it comes to wind turbine manufacturers, apart from Enercon, we no longer have any purely German manufacturers of noteworthy size. Enercon still has a global market share of 2.4 percent and is therefore no longer among the international top 10. The Spanish-German companies Siemens-Gamesa RE and Nordex-Acciona together have a share of 16 percent. At the moment I see no signs of a resurgence or further growth among German manufacturers. Chinese manufacturers are also clearly ahead when it comes to the top turbine developments in the offshore and onshore sectors. If you believe the announcements, four of them are about to launch offshore turbines with 16 to 22 megawatts of power and 252 to 310 meters of rotor diameter – as well as onshore turbines with 8 to 10 megawatts with up to 220 meters of rotor diameter. Western manufacturers currently offer performance data of 14 to 15 megawatts and 220 to 236 meter rotor diameters offshore as well as 7 megawatts with a diameter of up to 170 meters onshore. When it comes to wind energy locations, these seemingly small differences mean worlds. To put it simply, the potential energy yield of the systems increases quadratically with the rotor blade length – i.e. linearly with the swept rotor area.
The Chinese world market share is now well over 50 percent. What needs to be done to give Europe a bigger piece of the pie again?
The industry, especially in Germany, has to deal with constantly changing political and economic conditions. The expansion plans are constantly changing, but the excessive bureaucracy for planning and approving new systems and wind farms is being reduced very slowly. We already had a stable annual increase of four to five gigawatts of installed wind energy capacity in Germany from 2014 to 2017. In order to achieve our current expansion goals, we would have to establish an average of eight gigawatts of growth every year by 2030. But now we have broken down to two to three gigawatts. In industry, such ups and downs often lead to the termination of the commitment. One example are foundries that produce the hubs of wind turbines – huge parts weighing 50 to 150 tons. Due to the ups and downs of expansion plans, there are no longer enough German manufacturers who are casting such large hubs for wind energy. That’s why manufacturers buy in China or elsewhere in the world. Unfortunately, the situation in other European countries is not much better. In other words: Through short-sighted political decisions, we have clearly damaged an important economic branch on which we Europeans sit. A complete cure currently seems unlikely. The European photovoltaic debacle with economic relocation and thus job losses threatens to be repeated in wind energy. In Germany alone, tens of thousands of jobs have been lost in the wind energy industry in the last five years. However, the political focus is more on the around 20,000 jobs that are associated with the coal phase-out. In my opinion, balanced, sustainable economic policy should look different.
How do you assess the development of wind energy use in light of climate change?
Wind energy is an important component in reducing CO2-Reduce emissions globally. However, they alone will not get us under control of the climate problem. No wind turbine installed today is CO22-free. If you look at the energy consumption that was used to produce the wind turbine, it will pay for itself in terms of energy after 6 months in windy locations and in a maximum of 15 months in less productive locations. With the exception of hydropower, photovoltaics and solar thermal energy, this cannot be achieved with any other energy source today. The challenge of the fluctuating power output of these sources remains. Technical solutions already exist for this, but they still have to reach the necessary market maturity for ramp-up. The political and social conditions can greatly accelerate the process, but can also slow it down massively. That’s why every individual is asked to think differently and question statements. Bold statements such as “that is not possible” or “that is priceless” are demonstrably not correct and are not helpful for a positive overall development against climate change.
Will the yields of wind turbines improve as a result of climate change?
To put it a little differently, this is a current research topic. Although global and regional wind conditions are almost certainly changing due to climate change, we do not yet have a clear answer to the question of whether this alone will lead to more wind energy. Theoretically, the opposite could also be the case. However, we are currently more concerned with the question: What does a massive expansion of wind energy mean for regional wind conditions or the microclimate, for example through changes in precipitation or cloud formation. In science, we have a responsibility to illuminate as many sides as possible – as we understand it, this also includes the potentially negative aspects of new technologies. There are currently no answers to this question. An analysis is technically extremely complex and is subject to many uncertainties.
How will the increasing extreme weather conditions affect wind turbines?
Basically, all wind turbines take extreme events into account – such as hurricane gusts or the so-called 50-year gust, comparable to a statistically extremely rare monster wave on a ship. The new offshore turbines are typhoon, hurricane and hurricane proof. They are certified accordingly, but not tested. In practice, this will be done very pragmatically by the real storms that the systems have to survive during their 20 to 30 years of operation. I am currently not aware of any event in which a typhoon or hurricane caused critical damage to a wind farm. As with all technical systems, events occur sporadically, but they have nothing to do with fundamental design errors. The reasons for the rare accidents of wind turbines can be easily explained in each incident and do not give cause for alarm. Manufacturers and inspectors do a good job.
How realistic is the risk of falling victim to a widespread power outage, or blackout, due to an increase in wind energy?
Even when I was studying three decades ago, energy suppliers and grid operators said at conferences and public panel discussions: If we have 5 percent wind energy, then the grid will no longer be able to handle it. Now on some days we produce almost 100 percent of our electricity from renewable sources – and it’s going well. However, the networks and their operational management are still too focused on large power plants. This urgently needs to be changed. However, the story of the constant threat of a potential blackout due to the expansion of wind energy use remains a constant in the discussion. And she still comes from the same place as she did 30 years ago. Wind turbines and thus wind farms behave on the grid as their operating software tells them to; the technical specifications come from the grid operators. Dealing with scenarios and generating working solutions would be the right answer instead of often insisting on the status quo and your own sinecures and waiting.