About the person

The challenge

In 2023, renewable energy sources already contributed 52 per cent to the gross electricity generation in Germany. More than half of this was provided by the use of wind energy, the share of which is expected to increase further in the years to come. In this context, offshore wind energy, which according to European plans is to form the backbone of CO2-neutral electricity generation by 2050, will explicitly come into focus. An expansion to the targeted 450 GW of installed capacity in Europe, however, requires a continued reduction in electricity generation costs, which are significantly lower compared to conventional energy sources – but a direct comparison with the more cost-effective onshore wind energy shows that this is the key challenge.

From the lecture

The advantages of offshore wind energy compared to its onshore counterpart are obvious. In particular, higher wind speeds are consistently available at sea than on land, which means that a reliable generation of electricity from wind energy can be guaranteed there – even during dark doldrums on land.

A variety of different approaches are used to reduce the costs of the turbines in order to enable more economical electricity generation. As the output of wind turbines increases quadratically with the rotor diameter and installation times and logistics are faster and cheaper in relation to output, the size of new turbines has been continuously increasing for years. Additional concepts include the monitoring of structural behaviour by means of sensors, which enable damage to be detected at an early stage. This allows the systems to be maintained depending on their condition and their operation to be regulated accordingly. Simulation models can support the systems over their service lifetime as so-called digital twins. The simulation data can be constantly re-validated using the data from the real turbine in order to obtain a better model. As the service life of wind turbines is mostly designed for 20 to 25 years based on a conservative calculation, the models based on real data enable the service life to be recalculated after 15 to 20 years.

In most cases, it is possible to continue operating the systems for longer. Recalculation with the help of classic simulation models is extremely complex, as many different combinations of environmental conditions have to be simulated. More recent AI-based methods – so-called metamodels – learn the correlation between the input and output variables of the classic simulation model, such as wind speed and service life, and can then be used to replace it in order to save computing time.

Perspectives

The costs of offshore wind energy have already dropped significantly in the past few years. The realisation of the energy transition, especially through the expansion of offshore wind energy use, represents a multi-thematic challenge that has to be tackled through interdisciplinary cooperation between different disciplines such as engineering and computer science. An extended service life of the turbines and effective damage management through sensor-based structural monitoring and computer modelling provide a valuable contribution to this.