North Sea waves in Braunschweig for offshore wind energy Science Minister Falko Mohrs starts summer tour at TU Braunschweig

How can offshore wind turbines be further developed and improved to drive forward the energy transition? How can the marine habitat be protected at the same time? The Leichtweiß Institute of Hydraulic Engineering at Technische Universität Braunschweig is investigating these questions using the new saltwater wave current channel, the only one of its kind in Europe. At the start of its summer tour ‘Wind. Water. Wadden Sea’, Niedersachsen’s Science Minister Falko Mohrs visited the test facility on 2 September to find out about the research taking place there. A total of seven institutes and research facilities in the coastal region of Niedersachsen and in Braunschweig are on the programme of the summer tour.

Kick-off of the summer tour in the test hall of the Leichtweiß Institute of Hydraulic Engineering at TU Braunschweig: Niedersachsen’s Science Minister Falko Mohrs with TU President Angela Ittel and Professor Nils Goseberg. Photo credits: Kristina Rottig/TU Braunschweig

Niedersachsen’s Science Minister Falko Mohrs said: “As a state, we want to continue to make determined and rapid progress in the generation of renewable energy. Offshore wind energy is an important building block for Niedersachsen as a coastal state. The research carried out by the Leichtweiß Institute of Hydraulic Engineering and its cooperation partners can play a fundamental role in the development of more resource-efficient, sustainable and economical solutions for offshore technologies. The new saltwater wave current channel is the only test facility of its kind in Europe and is an impressive demonstration of the innovative strength of the Hannover-Braunschweig research region and its appeal far beyond Niedersachsen.”

“In addition to international collaborations, the Leichtweiß Institute of Hydraulic Engineering has focused its activities on highly topical issues related to the energy transition, which are particularly important for the energy state of Niedersachsen. TU Braunschweig is thus making an active contribution to highlighting the importance of its research and its results for society, for the evaluation of technical systems in our environment and for possible transfer projects,” emphasises the President of TU Braunschweig, Angela Ittel.

Sustainable use of the oceans

Research at the Leichtweiß Institute of Hydraulic Engineering and the Coastal Research Centre of Technische Universität Braunschweig and Leibniz Universität Hannover focuses on three main topics: the adaptation of coastal regions to climate change and accelerated sea-level rise, and the development of maritime technologies for sustainable use of the oceans. Under the leadership of Professor Nils Goseberg, 26 scientists from the Department of Hydromechanics, Coastal Engineering and Maritime Engineering are researching topics such as sustainable coastal protection against flooding and erosion, the effects of tsunamis and offshore wind energy.

These research tasks require interdisciplinary research cooperation with national and international partners such as the Niedersachsen universities in Hanover and Oldenburg, the Alfred Wegener Institute, the Technical University of Denmark, the University of Ghent and the Royal Netherlands Institute for Sea Research. Various experimental facilities are also needed. In LWI’s 5,600 square metre test hall, hydraulic model tests can be used to investigate sea conditions, coastal morphology, structural loads and interactions between waves and vegetation.

Strengthening the Braunschweig-Hannover research location

At the end of April 2024, the Leichtweiß Institute for Hydraulic Engineering was expanded by a further research facility in the form of the saltwater wave current channel, which once again decisively strengthens the unique selling point of the Braunschweig-Hannover research location in the fields of coastal engineering, maritime construction and maritime technologies. In addition to the large wave current channel (GWK+) of the Coastal Research Centre, the already extensive portfolio of small and large test facilities has been expanded. “With the saltwater wave current channel, we are adding to the unique ensemble of test facilities in Europe under the umbrella of the Coastal Research Centre, enabling us to use realistic seawater to assess and understand the environmental influences of technical facilities in and around the sea,” explains Professor Nils Goseberg, Director of the Leichtweiß Institute of Hydraulic Engineering and Professor of Coastal and Maritime Engineering.

Seawater, waves and currents are combined in the 30 metre long and three metre wide channel. The two wave machines can generate waves up to 80 centimetres high. In addition, four pumps provide the current. The research projects use ultrasonic sensors to detect the water level, camera systems, speed measurements and force-torque sensors. All underwater systems have special requirements in terms of pressure tightness and resistance to seawater. “Innovations in the field of maritime technologies can be developed on the way to a higher level of technological maturity with the special experimental equipment of the saltwater wave current channel,” says Dr. Clemens Krautwald, research associate in the EnviSim4Mare project.

Influence of bivalves on offshore structures

Research at the Department of Hydromechanics, Coastal and Marine Engineering focuses on the interactions between marine organisms (mussels and algae) and their habitats with offshore installations (e.g. wind turbines on the open sea). As part of the EnviSim4Mare project, funded by the German Federal Ministry of Economics, the influence of marine vegetation on the stability of the support structures of offshore turbines is being investigated. On the other hand, the scientists are working with European partners in the EU project INF4INiTY to investigate new types of artificial reef structures on floating wind turbines. As part of the Anemoi project, funded by the Interreg North Sea programme, the researchers are investigating the impact of the turbines on the environment. In particular, they are looking at chemical and particulate emissions.

These important research questions can now be investigated for the first time in the saltwater wave current channel under realistic sea conditions. Wave and current conditions as well as temperature, salinity, pH, oxygen and nutrients will be taken into account. The data and knowledge gained from the experimental studies can be used to improve the design of offshore wind turbines so that they can be built and operated in a resource-efficient and economical manner for as long as possible.

“With the increasing use of the sea for energy production and similar activities, it is becoming more and more important to understand the interactions between offshore structures, marine habitats and the biodiversity they contain. The issue of environmental impact and its assessment will also play an increasingly important role in tenders for the use of marine space in the future,” says Dr. Christian Windt, head of the Sustainable Marine Technology working group at LWI. “Research at the LWI contributes directly to this, and with our unique research facilities we can ultimately make a significant contribution to the sustainable use of our oceans.”

Leichtweiß Institute of Hydraulic Engineering (LWI)

The Leichtweiß Institute of Hydraulic Engineering at TU Braunschweig is named after its founder, Dr. Ludwig Leichtweiß (1925-1950). It covers the field of sustainable water research – from the mountains to the sea – in research and teaching. The LWI comprises the departments of Hydraulic Engineering and Water Morphology, Hydromechanics, Coastal Engineering and Lake Engineering, Hydrology and River Basin Management, and Waste and Resource Management.