Fast flow for firmer foundations

UK engineering hydraulics specialist HR Wallingford is working with offshore wind heavyweight DONG Energy as part of a project to develop what it firmly hopes will be the next-generation of wind turbine foundations.

Work underway in HR Wallingford’s recently opened Fast Flow Facility will help inform the design of a novel suction bucket foundation, and will ultimately lead to more cost effective seabed foundation solutions for the renewable energy industry a company spokesperson has claimed.

Laser scanners measure the movement of sediment around a 1:32 model of a suction bucket foundation, helping scientists to understand the potential impact of scour. As offshore wind farms move into ever deeper water, developers are exploring alternatives to the traditional monopile foundation in order to reduce costs and keep the technology competitive within the energy marketplace. HR Wallingford is helping DONG Energy refine the design of one such alternative – the suction bucket foundation – as part of a research project to determine how these structures interact with, and impact upon, the hydrodynamic conditions and the seabed.

The action of waves and currents can lead to erosion of the seabed around wind turbine foundations. This phenomenon, known as scour, poses a risk to the stability of the foundation and, in extreme cases, has the potential to cause structural failure. Although scour is relatively well understood for traditional monopile foundations, the same is not currently true for complex foundation types.

Prof Richard Whitehouse, HR Wallingford technical director told Maritime Journal: “This research with DONG Energy will help us to develop greater certainty in the prediction of seabed response and design more efficient foundation solutions. Ultimately this will help to make offshore wind developments more costs effective, and developments in exposed locations and deeper waters more economically viable.”

Designs that have been shown to be reliable in the laboratory are likely to be adopted by developers as there is also a requirement for the technology to be proven before its application for use in large-scale developments.

Andreas Roulund, lead oceanographic engineer at DONG Energy Wind Power said: “The ability to have novel designs tested by physical modelling is crucial for development of our foundations. We can observe how the seabed responds to the foundation in the extreme conditions found in the North Sea. We have found the new Fast Flow Facility at HR Wallingford tailor made for this purpose.”

Since launching the Fast Flow Facility at the end of 2014, HR Wallingford says it has been examining the complex interaction of waves, current and sediments at a larger scale and in more detail than was previously possible, helping clients to optimise designs more effectively and minimise project risks.