Wave loads on monopile offshore wind turbines

Australia has a unique opportunity to capitalise on the consistent high-velocity wind resource prevalent along much of our extensive coastline. Interest in developing offshore wind projects in Australia has boomed since passage of the Offshore Electricity Infrastructure Bill 2021. In August 2022, the first six areas for offshore wind developments in Commonwealth waters were proposed. Most of the tentatively proposed projects are of utility-scale, 0.5-2 GW, so comparable to existing power stations.

Offshore wind farms typically contain around a hundred of individual installations – a turbine supported by a tower attached to a bottom-fixed or a floating foundation. Due to the need for their mass-production, the industry requires minimally conservative design, which is based on a detailed understanding of the relevant loading behaviour.

This talk will outline advances in our understanding of wave-induced forces on bottom-fixed monopile foundations, as these account for approximately 80% of support structures in offshore wind farms globally and are a likely candidate for the first offshore wind farms in Australia. We will present results from model-scale experiments from the UWA’s state-of-the-art Coastal and Offshore Research Laboratory at UWA (https://www.uwa.edu.au/facilities/corl). In the tests, the structures were instrumented with force transducers, and subjected to a range of wave conditions, including long-period waves typical of swells along the southern Australian Shelf. The analysis of the measured forces is currently ongoing, and we hope it will shed light on wave loading mechanisms in Australian waters.