Posters

Abstract

Phenomenal offshore wind capacity targets have been set by countries across the globe. The rates of development of offshore wind farm (OWF) projects will, necessarily, increase to meet these targets. As such, efficient flow of the correct information, at each interface of an OWF project lifecycle, is paramount. Design of the turbines and foundations is a key part of the development of an OWF, and requires detailed understanding of the site atmospheric and oceanographic conditions. With increasing pressures on achieving lower cost of energy in the backdrop of increasing supply and material costs, a drive for efficient designs which reduce conservatism whilst maintaining safety is underway. Having a clear and accurate understanding of the conditions at an OWF site will allow any unnecessary conservatism to be reduced. In this spirit, the authors would like to share useful and practical advice that will contribute to the progression of the industry as a whole, regarding the characterisation of Turbulence Intensity (TI) as an input to OWF design. TI is a required input for both turbine and offshore foundation design as part of Integrated Loads Analyses (ILAs). Although TI is largely a driver of fatigue loads, it is also necessary to quantify extreme TI levels for Ultimate Limit State (ULS) simulations. Industry standards require a Normal Turbulence Model (NTM) and Extreme Turbulence Model (ETM) to be defined for a site. The standards provide equations to derive approximations for these models. Whilst the NTM is generally well understood, in the authors' experience, a consensus on the derivation of an appropriate ETM for an OWF site is less well established. The authors present a comparison of various NTMs and ETMs, at selected offshore measurement sites, providing confidence in these approximations and clear advice on how to apply them in the context of design and certification.