In the town of Gaildorf near Stuttgart, Germany’s energy revolution is taking shape – and it’s big. The town is home to the tallest wind power plant in the world, along with some clever engineering work. It combines wind turbines with a pumped-storage power plant to create a natural energy storage. The cabling for this facility was provided by LAPP. We report from southern Germany.

The view from the bottom is almost as spectacular as that from the top. The wind turbine measures 246 metres from the ground to the tip of the rotor. The town of Gaildorf may only have 12,000 inhabitants, but it is now also home to the world’s tallest wind power plant. But it’s not just the size of these four giant turbines that makes them so impressive. They are also capable of storing the energy they produce on site.

This was achieved by means of an active reservoir: a water tank in the base of the wind turbine. The reservoir can hold 7,100 cubic metres of water, and adds another 40 metres to the turbines’ height. The towers themselves stand in enormous passive reservoirs. When the wind park generates more energy than required, water is pumped from the lower to the upper reservoirs. If electricity in the network is scarce, the water drops 200 metres down into the valley and powers three turbines. Wind turbines and pumped-storage power plants are nothing new. But combining them at the same location in the same structure is a real innovation.

The Gaildorf natural energy storage

The three rotor blades convert wind energy into 3.4 megawatts of electricity. Each wind turbine can generate over 10 gigawatt hours of energy per year, enough for around 2,500 four-person households. The three turbines in the valley generate 16 megawatts, while the energy storage has a capacity of 70 megawatt hours.

Website

The components of the water battery, © Max Bögl Wind AG (Website)

Harvesting wind and breaking records

The record height is down to the concrete base. The 40-metre-high structure stabilises the turbine itself, which measures 178 metres at its hub. Add on the 137-metre rotor diameter and you have a world record.

But the wind farm is less about numbers than it is about pure energy. Every additional metre increases the energy yield. The concrete structure is a masterpiece, using materials and construction techniques that have never been used before in this combination anywhere in the world. “The construction is top secret”, explains site manager Markus Meyer. All he tells us is that the turbines were assembled using the tallest mobile crane in the world, of which only three exist.


Wind and water


At the wind park in Gaildorf, up to 160,000 cubic metres of water flows 200 metres through plastic pipes from the concrete bases of the towers to the turbine house. That is 4 metres more than Glymur, the second-highest waterfall in Iceland.

 

Video: © Max Bögl Wind AG (Website)

Cables from LAPP

But let’s back up a bit. The last medium-voltage cables to be installed lie wrapped around large wooden drums inside a container on the construction site, waiting to be hauled up inside the massive tower. Professional industrial climbers, hanging from ropes inside the tower, pull the cables up and secure them to the metal framework. This massive project is a huge challenge for both the climbers and the cable.

It is also an ambitious project for the cable supplier LAPP. This is due to the complex combination of wind energy and pumped-storage technology.

Leaving nothing to chance

The four wind turbines are provided by GE Renewable Energy. The company has demanding requirements when it comes to the electrical systems, including the cable in the tower and nacelle. “All of the specifications, such as the dimensions and resistance to temperature, torsion, weather and other factors, were described in precise detail”, remembers Andreas Müller, who is responsible for the wind energy sector at LAPP.

His colleague Michael Bodemer, Head of Project Sales Germany at LAPP, proudly adds: “The cables used here are highly sophisticated. There were also demanding requirements for the cutting, marking, labelling and special cable drums. In order to even make it to the final short list, we had to offer a full-service package.”

View of the wind turbine’s cable shaft. The cables were supplied by LAPP.

While LAPP is pleased with the successful project, it has no time to rest on its laurels. That’s because Gaildorf is just the beginning. Max Bögl Wind, inventors of the combined turbine and pumped storage plant hope to market the design around the world. This would be a welcome challenge for LAPP, as it is the greatest tasks that help you grow the most.

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