On the quay in Cuxhaven, countless nacelles made by Siemens Gamesa Renewable Energy are waiting for the transport ship which will take them to their operation site. Production is in full swing and every year approx. 250 nacelles leave the plant which is considered to be the world’s most modern.
Cuxhaven started production in 2018. Generators, hubs and the so-called back-ends are assembled on three lines and put together on a fourth production line. Automation of production is a crucial key to lowering costs and achieving economies of scale, but the components are large and the quantities low compared to other industries, which is why there is still a large amount of manual work in Cuxhaven.
The generator is the heart of the direct drive offshore turbines. This is where the energy is produced by a ring of permanent magnets rotating around the stator. The correct distance between the magnets and the stator is crucial for efficiency. To achieve maximum output, the air gap between the two components needs to be as small as possible, but equally, the components must not get too close to each other.
Until now, colleagues at the plant have adjusted this distance in many small steps. They positioned the stator, measured the change, re-positioned the stator and so on, until the perfect position was achieved. This time-consuming and imprecise method seemed to us to need considerable improvement. We came up with the idea of automating this step and making production easier and more intelligent with the aid of digital technology.
Thanks to funding from the European Union and NBank in Lower Saxony respectively, as well as the support of the company management, plant management and the colleagues on the generator line, who allowed us to carry out our test during operations, we succeeded in record time, together with some of our partners, in going from the initial idea to a demonstrator to the implementation of a new system - the flexible stator adjustment centre (FSAC).
The measurements are now done by lasers and software delivers the data to colleagues in real time. Human errors are minimised, the time required is halved and at the same time the generator’s performance is increased whilst production costs are reduced. The system is flexible and can easily be adjusted to make the new larger turbines for the 11 MW and 14 MW plants.
With the FSAC and its accompanying patents, Siemens Gamesa can add a new chapter to its success story of more than 1,000 installed direct drive turbines and further expand its technical edge. Our invention means more renewable energy at lower costs. This success, and the freedom as engineers to be able to try out and implement new ideas, now spurs us on to identify other possibilities to make production smarter and thus further increase the competitiveness of offshore wind power in order to be able to supply even more people with clean, cheap energy.
Authors: Marius Fürst-Sylvester, Benjamin Henriksen, Thorsten Schneider, Martin Bach Soerensen
The authors are development engineers for Siemens Gamesa in Cuxhaven and Brande. They originally came together as a team to take part in an in-house ideas competition. Today they manage the project “Flexible nacelle production for wind turbines of the future in Cuxhaven” of which the FSAC is a part, as well as other projects in the field of manufacturing intelligence.