Swells Neutralised During Offshore Maintenance

In future, the maintenance of, for example, wind turbines at sea, will be made easier and safer by a Delft invention, the ‘Ampelmann’, which compensated for swells at sea. Tests with scale models have shown that by mounting the working platform of maintenance ships on an Ampelmann, the platform will remain still and work can take place more efficiently. On Friday 18 February at TU Delft, the invention will be demonstrated to representatives of the Ministry of Economic Affairs, the director of Shell Nederland, the chairman of the TU Delft Executive Board and other governmental, scientific and industrial representatives.

The Ampelmann uses the same technology applied in flight simulators, a mechanical system with six large hydraulic cylinders. By accurately measuring the movement of the ship, and controlling the cylinders accordingly, the platform can be held in a fixed position relative to the object being worked on. This also makes it possible to safely board the structure with a simple bridge. This makes such off-shore structures far more accessible for maintenance crews. Currently, it is impossible to work on off-shore wind turbines 20 percent of the time, due to swells at sea. Using the Ampelmann, this could be reduced to around seven percent. Improving maintenance can increase production and efficiency.

At the European Wind Energy Conference in 2004, PhD student Jan van der Tempel won first prize for this idea in a field of 300 international entrants. “In Europe, about fifty wind parks have been planned, each with 30 to 300 turbines. Moreover, world wide there are seven thousand offshore production units that could benefit from this technology. There is therefore a great interest in the concept.” Van der Tempel will soon start his own company, which will develop a prototype of the system in 2006. The patent remains in the hands of TU Delft.