Tsunami Risk to UK Offshore Wind: Paleo-evidence and numerical model simulation

The UK produces over 45% of its energy through renewable means, the majority of this through wind power. The mainstay of this capacity is located offshore in the North Sea, a region and capacity which is set to significantly expand in the coming years. Given the increasing importance of offshore wind generation for UK energy security and net zero goals, it is becoming ever more vital that all stages of this generation method be risk assessed to ensure that no single event can cripple the nation’s energy supply.High Magnitude, Low Frequency events (HMLF), such as tsunamis, are often overlooked during risk assessments due to their infrequent nature. This thesis locates and analyses sedimentological evidence of one such HMLF event, the Storegga tsunami, and shows that such events have propagated through the North Sea and impacted upon the eastern coast of the UK. Specifically, sedimentological evidence for the Storegga tsunami is located in cores from Howick Burn in Northumberland.Using this data as a baseline, this thesis then uses inverse and forwards analysis models to determine the possible extent and severity of a Storegga-scale tsunami event in the present day. Inundation maps are utilised to assess potential damage to land-based assets of the offshore wind industry and national grid as a whole, and these suggest that a tsunami of a similar magnitude to Storegga could lead to a loss of between 9.1 and 10.3 GW of power generation, which amounts to 39% of UK power generation. About half of this loss is through the impacts upon offshore wind infrastructure, especially due to the damage to onshoring cabling sites and Operations and Maintenance (O&M) bases.This thesis therefore concludes that the risk from tsunami to offshore wind infrastructure is currently overlooked. Given the increasing importance of offshore wind to UK energy production, and the vulnerability of some stages of this generation method, it is important that more consideration is given to the protection of this infrastructure against the impacts of a tsunami.