New research proposes safer offshore wind turbines for earthquake-prone regions

Researchers at UTS have proposed a novel cable-stay reinforcement system that could significantly improve the resilience of large offshore wind turbines exposed to the combined effects of earthquakes, wind and waves.

The study, led by Professor Behzad Fatahi from UTS, investigated a new cable-stayed tower concept for a 15 MW offshore wind turbine supported by a monopile foundation. The research was conducted by UTS PhD candidate Nadeem Fairley, with industry support from Dr Aslan Hokmabadi from Arup.

Offshore wind is expected to play a critical role in the global transition to renewable energy. However, many high-potential offshore wind regions, particularly across the Asia-Pacific, are also located in seismically active zones. This creates a major engineering challenge: ensuring that increasingly large offshore wind turbines can withstand not only wind and wave loading, but also severe earthquake excitation.

The research team used advanced numerical modelling to compare a conventional offshore wind turbine tower with a newly proposed cable-stayed tower design. The cable-stay system uses high-tensile steel cables and supporting struts to increase the tower’s flexural stiffness and reduce damaging dynamic responses during extreme loading events.

The simulations showed that the cable-stayed design substantially reduced tower accelerations, stresses and deformation. In several cases where the conventional turbine model experienced yielding or buckling, the reinforced cable-stayed tower remained structurally intact.

Professor Behzad Fatahi said the findings could open a new pathway for safer and more resilient offshore wind infrastructure.

“Offshore wind turbines are becoming larger and are increasingly being proposed in regions where earthquakes are a real design concern,” Professor Fatahi said.

“Our research shows that a relatively simple structural reinforcement concept, inspired by cable-stayed systems used in bridges and towers, can significantly improve the dynamic performance of offshore wind turbines under combined earthquake, wind and wave loading.”

The study found that the cable-stay system helped reduce internal forces in the upper sections of the tower by increasing structural stiffness and reducing resonance with higher vibration modes. It also helped prevent sectional ovalisation of the tower, a deformation mechanism that can contribute to buckling in thin-walled turbine towers.