Offshore wind farms are currently planned or built at scale on many continental shelves around the globe and it is predicted that ~380 GW of new offshore wind capacity is going to be added in the next 10 years (four times the current capacity). With offshore wind farm (OWF) sites getting larger (some > 900km2), deeper and further offshore and with more plans for floating turbines deployment, the challenge is not small, and geoscience is posed to play one of the key roles in it.
In the first part of this this lecture we will introduce the process of ground modelling for offshore wind developments including the turbine array but also subsea cables and landfalls. We will also discuss similarities and differences in workflows, data requirements and specific geoscience expertise between offshore wind and oil and gas sectors. And the differences between fixed and floating wind developments.
The second part of this lecture will focus on case studies showcasing the technical aspects and geoscientific challenges of ground modelling and geohazard assessment. In particular we will (1) discuss development of ground model (GM)and quantifying GM uncertainty across a former ice marginal setting using ultra-high resolution seismic (UHRS) data in the Baltic Sea, (2) look at how understanding of crustal scale isostatic movements and relative sea level changes can help with Cable Burial Risk Assessment in Canada and Scotland with a particular focus on submerged organic-rich muds and peats, (3) touch on sediment mobility and submarine geomorphology aspect of offshore wind development and (4) show how seismic geomorphology approach using 3D HR seismic data and process-based seismic interpretation can help with identifying engineering ground units and geohazards accelerating the GM process. This is relevant for all offshore wind sites but here it will be discussed in the context of formerly glaciated Northern Hemisphere continental shelves where the shallow subsurface (here defined as first ~200m below seabed) was affected by multiple phases of ice sheet advance and retreat during the Pleistocene, leaving a complex mosaic of glaciogenic sediments, glaciotectonic deformation, evidence for periglacial alteration of sediments, all that interbedded with terrestrial and marine sediments deposited in non-glacial settings.