More effective wind turbines: power even when the breeze is mild

Status: 01/16/2022 09:39 a.m

Wind power plays an important role in the energy transition. Two engineers are focusing on the development of inexpensive, effective systems: A lot of electricity should be generated even at low wind speeds.

By Jens Eberl and Markus Wollnik, WDR

Markus Becker and Benno Sandmann, managing directors of windwise GmbH from Münster, proudly hold a small wind turbine in their hands. It is the model intended to illustrate their idea. With this new system, wind energy can be used much more effectively. Because there is currently a problem with the wind: Previous wind turbines mainly produce electricity when there is a lot of wind. However, the grid often cannot absorb that much electricity at all, because the amount produced in these phases exceeds consumption.

There are hardly any storage options, and transporting electricity across the country is too expensive. This is where the two engineers from Münster come in. “We try to make the electricity yield more even. And to generate the electricity when it is most valuable. Namely when there is little wind. When the grids are not yet full,” says Sandmann.

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Lighter, less powerful, cheaper

With electricity it is different than with water, for example. When it comes to water, there are reservoirs. There it is collected and then used when it is needed. Wind is processed when it is there. The current wind turbines are misdesigned, the engineers argue. They are particularly suitable for strong winds, they do not work as effectively in weak winds. “You can compare that a bit with a VW Golf, which can be delivered with 50 hp or with 150 hp. Normally, you never need 150 hp or only very rarely. And that’s the same with wind turbines,” says Becker.

A look into the machine house: the turbine is being tested in Aachen.

Image: MWIDE NRW/Andreas Buck/maxcap-windwise GmbH

The system from Becker and Sandmann is built like the Golf with 50 hp: lighter, less powerful and significantly cheaper. In strong winds, it even has to be regulated down so that it is not overloaded. “Normally, the rotor blades are flat in the wind, they can be rotated around the longitudinal axis, which reduces the stress on the components at the same time,” says Becker. But that’s not a problem, since strong winds mean there is more electricity in the grid than is needed anyway. When the wind is weak, the system works just as well as the large ones – but then it is more effective because it is lighter and cheaper to produce than the large wind turbines. This could also make them interesting for use in regions with little wind.

Rethinking wind energy

So the idea of ​​the two engineers is not a technical revolution. It’s more of a new way of thinking; it is a philosophy of how to use wind more effectively.

The reason for the previous construction of wind turbines is also the result of a political orientation. It is about the so-called feed-in tariff according to the Renewable Energy Sources Act. This regulates the preferential feeding of electricity from renewable sources into the power grid and guarantees their producers fixed feed-in tariffs. This means that the operators of the systems receive a fixed price for every kilowatt hour they deliver. It is only about the electricity that is fed into the grid; whether it is also used by the consumer is irrelevant. Accordingly, many operators are concerned with producing as much electricity as possible, because it is paid for – no matter how much it is worth to the energy supplier.

But that’s not effective, and it’s not up-to-date anyway, says Becker. “If the operators had to market their electricity themselves, they would act differently,” he is convinced.

Effective use of wind as a goal

With their development, the two people from Münster want to encourage rethinking and thus prevent a lot of energy from being wasted. Support comes from science. Peter Vennemann, Professor of Energy and Environment at the Münster University of Applied Sciences, finds the project very interesting. Wind turbines could be built much cheaper. “Currently you buy a lot of copper, steel for the entire drive train, for the bearings, for the gearbox, and then it’s only used very rarely. And when it’s used, there is so much wind and electricity in the grid that the price is almost zero, so you don’t have any revenue,” says Vennemann.

The rethinking has already begun, says engineer Becker. The market is in upheaval – also due to the change of government in Berlin. The goal is very clear, to use the energy more effectively and not blindly pay for what is fed into the grid.

EU supports the project

The development of Becker and Sandmann is making progress. The machine house of the turbine already exists. It was built by a machine factory in Erkelenz and has a total length of twelve meters. The EU has contributed around four million euros in funding. Together with the Technical University in Aachen, Becker and Sandmann have already put the prototype through its paces. Now the turbine only has to be set up. The municipal council in Lienen has already approved. If the district of Steinfurt gives its approval, we can start.

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