Directionality in prospective Northern UK tidal current energy deployment sites

The directionality of the tidal flow throughout the tidal cycle has important implications for tidal energy capture with respect to turbine performance, capacity factor, and structural loading. There has been a tendency to infer that energetic sites possess near bi-directional flows or that there are sufficient sites with near bi-directional flows such that more omni-directional flow tidal currents can be neglected. This technical note investigates the connection between directionality and the incident kinetic energy density of tidal currents in the Northern United Kingdom. It demonstrates a positive correlation between these flow parameters and quantifies this through the analysis of real tidal velocity data.

► The directionality of tidal currents is examined with respect to flow energy density.
► Flow directionality is quantified using Principal Component Analysis.
► A positive correlation is shown to exist between flow energy and directionality.
► At energetic sites, 89% of the flow energy is aligned within ±20° of bidirectionality.