UK Floating Offshore Wind Turbine Test Facility (UKFOWTT)

The UK presently has the largest installed capacity of offshore wind, accounting for 36% of global capacity in 2017. The offshore wind industry contributed 9.8% of the UK's power in the 3rd quarter of 2019. In the 2019 Offshore Wind Sector Deal, the sector committed to building up to 30 GW of offshore wind by 2030, with an ambition of increasing exports fivefold to £2.6bn. The Committee on Climate Change has recommended an installed capacity of 75 GW by 2050.

Nearly all offshore wind turbines installed to date have been mounted on fixed bottom support structures located in water depths up to 60 m. Given the limited availability of suitable sites at such water depths, Floating Offshore Wind Turbines (FOWT) will become increasingly important over the next decade to achieve the Offshore Wind Sector Deal goals and to help achieve the UK target of net zero greenhouse gas emissions by 2050. The Sector Deal highlights the need for government to develop frameworks to support the advancement of technologies such as FOWT.

Physical modelling is a critical tool for the development of a floating offshore wind turbine and is recommended in most development guidelines. This is especially true at early stages of the development of new concept with a technology readiness level (TRL) between 1 and 3. Testing model devices at scale in the controlled environment of a laboratory has many advantages. These include the proof (or otherwise) of novel design concepts, the ability to test in systematically changing conditions and the ability to test in conditions which have low occurrence probabilities (i.e. extreme events). Quantitative measurements of motions and loads on scaled FOWT models can be made with much greater ease and accuracy then at full scale at sea. Qualitative observations are far easier to observe as well. If done correctly these measurements and observations can lead to the evolution of device designs and concepts and reduce the chance of costly failure; if and when devices are eventually deployed at sea.

The University of Plymouth COAST laboratory (www.plymouth.ac.uk/coast-laboratory) is a state-of-the-art research facility for the study of wave and current interaction with offshore and coastal structures using scaled physical modelling. It houses the Ocean Basin, a 35 m x 15.5 m tank with a raisable floor that can enable testing at water depths between 0.5 and 3 m. This project will establish the UKFOWTT - UK Floating Offshore Wind Turbine Test facility within the Ocean Basin. In addition to the wave and current generation that COAST can presently deliver, UKFOWTT will add wind generation to COAST. This will consist of a bank of axial fans, mounted on a gantry spanning the tank width and have the ability to generate winds up to 10 m/s, model gusting and have a controllable wind profile. The generator will be moveable vertically from just at the water's surface to approximately 1 m above. It will be rotatable +/- 30 degrees relative to the basin, enabling the influence of wave/current/wind/model alignment to be investigated.

The primary purpose of UKFOWTT is to enable both fundamental and applied research in topics related to Floating Offshore Wind. This will be a unique facility within the UK, enabling systematic physical modelling experiments with wind, wave and currents simultaneously. Data collected from physical modelling can improve understanding of the underlying physics, support development of analytical theories and validate advanced numerical models. It is also a low risk method of testing new and novel concepts. UKFOWTT provides the associated instrumentation to support these studies.

UKFOWTT will also support research in other sectors of Ocean and Coastal Engineering disciplines, including the Oil and Gas sector, floating wave, tidal and solar energy, autonomous vessels, launch and recovery operations and coastal defenses.