Site-specific tidal current resource information is required to optimise power generation from turbines and develop realistic design loads. This is challenging for length scales ranging from several kilometers (preliminary site investigation) to less than one hundred meters (micrositing) and time scales ranging from a month (power generation estimates) to fractions of a second (descriptions of turbulence). Approaches to collect multi-scale data in an accurate, cost-effective manner are, therefore, of interest to the tidal energy industry.
Results are presented from a multi-year resource characterisation study in Admiralty Inlet, Puget Sound, WA (USA). This site has been identified as having the greatest tidal energy resource potential in the continental United States and a pilot-scale tidal energy project is currently under development. Shipboard surveys using Doppler profilers are shown to effectively characterise operationally significant kinetic resource gradients at length scales down to 100 m. Survey effectiveness is benchmarked against ground-truth from simultaneously deployed bottom-mounted current profilers. This type of shipboard survey enables targeted long-term, bottom-mounted Doppler profiler deployments that can quantify, with high accuracy, the time variation of kinetic resources from monthly and turbulent time scales. Observations indicate kinetic resource variations greater than 10% can occur over distances less than 100 m.
