The interplay and incremental development of tidal stream arrays in the Pentland Firth

Abstract The development of tidal stream energy sites is constrained by numerous practical, technical, and accessible constraints, including changes in the flow caused by the presence of the tidal farm. Large and complex sites are typically developed incrementally and may involve multiple developers. This regional modelling case study of the Pentland Firth, widely regarded as one of the most significant global locations for tidal energy extraction, investigates these dynamics. This study examines scenarios for the incremental development of the Pentland Firth, incorporating assumptions regarding tidal farm design. The analysis considers a range of configurations, including variations in turbine density and the incorporation of shipping lanes within designated lease areas. The study finds that there are interactions between individually developed tidal farms of the site, but they are moderate with the power in a given farm unlikely to vary by more than 20% (based on a positive interaction), as a result of the development of other farms in other parts of the Pentland Firth. To minimise such array interactions, it is recommended that site leasing be based on the allowable thrust applied to the flow rather than on projected power generation. Furthermore, the findings suggest that the maximum power generated from turbines in the Pentland Firth, averaged over time, is unlikely to exceed approximately 1 GW, broadly consistent with most estimates in the literature.