Repowering of Offshore Wind Turbines
The InGROW research project investigated key conditions for the repowering of offshore wind turbines in its 2022 final report.
As a constructive solution approach, an adapted monopile structure with additional bracing on suction caissons was examined.
From the InGROW 2022 final report, Fraunhofer IWES
“With the German federal government’s goal of expanding offshore wind energy generation to 40 GW by 2040, new challenges arise for industry, research, and society. Offshore wind turbines (OWTs) are typically designed for a service life of at least 20 years, with a permit duration of 25 years for wind farms in the Exclusive Economic Zone (EEZ). However, depending on the planned reuse of the areas, the Offshore Wind Energy Act allows the application for a conditional extension of the operational period by an additional five years. Offshore wind farms in the German EEZ have been in operation since 2009. Initial estimates indicate that around 2,000 wind turbines in the German North Sea will need to be decommissioned by 2040. At the end of the operational phase, three end-of-life scenarios are generally possible: decommissioning, time-limited extension of operational life, and repowering. Motivated by the positive experiences in onshore repowering, this project focused on offshore repowering with an emphasis on foundations. The research focus was the development of a foundation concept for offshore repowering. The proposed technical solution for the foundation is based on combining an existing monopile foundation with a new support structure on suction caissons (also called suction buckets) as foundation reinforcement.”
The full report can be viewed here: