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More than meets the eye

Engineering for hybrid towers: csi develops interior fittings for modern wind turbines

Reading Time: 5 Min.

csi entwicklungstechnik supports construction company Max Bögl in engineering hybrid concrete and steel towers for wind turbines. As well as designing the complete interior fittings, including assembly platforms and support structures for ladders and elevator systems, we also take care of electrical engineering and additional work on the outer tower structure. Drawing on our experience of developing for the automotive industry, we ensure that all components are precisely planned and designed to be collision-free and, above all, can be installed safely. The result is a robust, timely, high-quality package of engineering services.

Joint engineering for Max Bögl's hybrid towers 

At csi entwicklungstechnik, limits don't apply to us when it comes to engineering precision, especially not industry boundaries. The principles that underpin our work in the automotive sector — precise design, clean planning, clear tolerance management and absolute adherence to deadlines — also apply to new industries.

This is currently demonstrated by our collaboration with Max Bögl, one of Germany's largest construction companies. The long-established Sengenthal-based company employs over 7.000 people and covers a broad technological spectrum, including building construction, civil engineering, modular construction methods, and its own magnetic levitation train system (TSB).

Max Bögl is the market leader in Germany for the manufacture, delivery and erection of hybrid towers up to a current height of 199 metres (hub height). Where possible, the rotor of the wind turbine is positioned even higher. This is because the taller the wind turbine, the higher its annual electricity yield, provided the tower is constructed with concrete at the base and steel further up.

This is precisely where our joint project comes in: the interior fittings of the hybrid towers.

Individual development as a challenge: each tower is unique 

At first glance, hybrid towers appear to be standardized. However, no two towers are the same.

Their heights vary, their geometry changes along their length — conical at the bottom and cylindrical at the top — and customer specifications cover details such as elevator type, ladder configuration and lighting. 

For engineers, this means that standardized specifications apply, but they must be precisely reinterpreted and transferred to each individual tower.

What sounds trivial is actually highly complex. For example:

A continuous ladder, on which an elevator cage is guided, runs the entire height of the tower. With a rung spacing of around 30 cm, this involves hundreds of rungs, the positions of which must match the locations of platforms, walls, and cabling exactly.

Interior installation and electrical engineering: precise, mountable and reliable

csi entwicklungstechnik supports Max Bögl in three key technical areas.

1. Interior installation – metal structures

We take care of the design, adaptation and planning of the following:

  • support structures for vertical ladder systems
  • support structures for lift guides
  • assembly platforms at various levels
  • all associated brackets, connections and sheet metal parts

This also includes PLM-compliant data management, ensuring that all designs are clearly documented, versioned and prepared for the approval process.

2. Electrical equipment, ranging from lamps to main wiring harnesses. 

At the same time, we are working on the electrical equipment, including:

  • complete cable routing from the tower base to the nacelle
  • positioning of lamps, plugs, sockets and switches
  • interface coordination for mechanical interior installation
  • digital data and plan creation for production.

Electrical and mechanical components are geometrically coordinated to ensure they can be easily installed and accessed, and that they do not collide with one another.

3. Support for the outer tower structure.

In addition to interior installations and electrical equipment, we now also provide engineering support for the tower's exterior
Our data-based management of individual support structures involves replacing structural components in digital models, adjusting relevant parameters, and ensuring that all changes are consistently and reliably reflected in the downstream planning process. 

‘I am thrilled that we are immersing ourselves in a new technical world and, at the same time, making a small contribution to the energy transition. I particularly enjoy our cooperative relationship with Max Bögl and the entire team.’
Philipp Silcher, csi project manager 

From CAD model to construction site: zero tolerance for errors

We develop all required planning and engineering documents, which are validated and approved by Max Bögl before they are transferred directly into the production process.
There, pre-assembled modules such as complete ladder sections or assembly platforms are manufactured. Once delivered to the construction site, the segments are lifted into position and bolted together using a crane.

This means that nothing can be 'adjusted' on site.

Drilling patterns, fits and tolerances must all be correct in the design and planning.

The requirement is clear: csi ensures that tower interiors can be assembled safely and precisely.

With extensive expertise and a comprehensive service portfolio, including transporting individual components and assembling entire systems, Max Bögl provides full‑scope construction services worldwide.

Development expertise from the automotive industry 

Our roots define our expertise.

By transferring proven automotive engineering skills into the construction industry, we generate measurable added value:

  • precise tolerance chains
  • effective assembly strategies
  • robust drawing and planning
  • reliable throughput times
  • clean data and change management
  • engineering with zero tolerance for error

Precise engineering results through interdisciplinary collaboration. 

The project is a collaborative endeavour involving a robust multidisciplinary team from the construction and electrical/electronics departments. This team has been working closely with Max Bögl's specialist departments since day one. Our speed and quality are highly appreciated, and our collaboration is constructive and purpose- driven. 


Precision as a principle, regardless of the industry

Hybrid towers made of concrete and steel are among the most challenging structures of the energy transition.
We are delighted that csi entwicklungstechnik can make a real contribution here, demonstrating that:

Engineering precision is not tied to a single industry.
It is a principle - and one we live by every day.

Philipp Silcher
Philipp Silcher

Project manager