Tidal energy resource characteristics are presented from a multi-year field study in northern Admiralty Inlet, Puget Sound, WA (USA). Measurements were conducted as part of a broader effort to characterize the physical and biological environment at this location ahead of a proposed tidal energy project. The resource is conceptually partitioned into deterministic, meteorological, and turbulent components. Metrics with implications for device performance are used to describe spatial variations in the tidal resource. The performance differences between passive and fixed yaw turbines are evaluated at these locations. Results show operationally significant variations in the tidal resource over length scales less than 100 m, likely driven by large eddies shed from a nearby headland. Finite-record length observations of tidal currents are shown to be acceptable for estimating device performance, but unsuitable for direct investigation of design loads.