innogy advances research on vibratory pile driving for offshore wind farm foundations

In 2014, six 21-metre piles, each more than four metres in diameter, were hammered and vibrated into the ground at an excavation pit in Altenwalde near Cuxhaven. The participating partners from industry and research were testing in practice what they hoped would become a new method for installing the foundations of offshore wind farms. Last weekend the research project entered its next phase.

“In the test environment two and a half years ago, the vibratory method was up to ten times faster and, in the light of certain installation criteria, proved to have a load-bearing capacity comparable to conventionally driven piles, as well as lower peak noise emissions – which is particularly important for protecting marine mammals,” explains Artur Czarnecki, project manager at innogy SE. “Yet we also wanted to collect additional data in order to further develop this alternative installation method in view of actual conditions on the open sea.”

The existing piles were therefore driven even deeper into the ground last weekend. The goal was to compare the resistance now with that measured immediately after the initial installation, thereby documenting additional load-bearing capacity in the foundations resulting from so-called adhesion effects. The collected data will be evaluated in coming months. The final results are expected within a year.

innogy project manager Artur Czarnecki believes the method will prove useful: “We have successfully completed the test series. Now we have to carry out a detailed analysis of the data we recorded. The data are very promising in terms of potential savings. This test has allowed us to take a major step forward toward actually using the vibratory process on the open sea.”

Mayor Ulrich Getsch of Cuxhaven is pleased at the progress that has been made: “This shows not only that there is wind here and that we offer the wind industry the right conditions, but that Cuxhaven has also established itself in the research sector. Because of the soil conditions created during the glacial period, this forward-looking process can be simulated here for use in the North Sea.”

innogy SE is leading the project. Further partners are e.on, Iberdrola and the Carbon Trust Wind Offshore Accelerator. The project is publicly funded by the Scottish government.

In the offshore wind sector, the research and development projects dedicated to foundation structures and their installation are typical of the work being done by innogy. The company draws on its over 15 years of experience in this area and strives, above all, to develop practical innovations and solutions. The Group can now apply the expertise gained during the installation of more than 400 offshore foundations.