A Modeling Study of Tidal Energy Resource Characterization in Cook Inlet, Alaska

The Cook Inlet in Alaska has been identified as one of the top candidate sites for tidal energy development based on a list of criteria, including tidal power density, market value, and transmission distance to urban centers. As the first step to facilitate development, a high-resolution tidal hydrodynamic model for Cook Inlet was developed to characterize the tidal stream energy resource using the unstructured-grid Finite Volume Community Ocean Model (FVCOM). The model domain covers the entire Cook Inlet and has a grid resolution varying from ~1000 m at the entrance to ~300 m in the upper inlet. The model is forced by tidal elevations obtained from OSU TPXO tidal database at the open boundary. As an approximation, meteorological forcing and river discharge was temporally not considered during this initial phase of study. Extensive model calibration was achieved by comparing model predictions against water level observations at three real-time NOAA tidal gauges and current measurements at a set of NOAA historical ADCP survey stations. The error statistics for both tidal elevations and currents confirm the model performs very well in capturing the tidal dynamics in the system. The model results indicate that tides in Cook Inlet change from progressive waves at the entrance to standing waves at the upper inlet, which partially explains amplified tidal ranges upstream. The model output was used to identify hotspots with high energy potential that warrant additional high-quality current and turbulence measurements. Lastly, a model scenario with a theoretical tidal turbine farm at the Forelands transect was conducted to evaluate tidal energy extraction and potential hydrodynamic impact.