Small but mighty: Evaluating the community-scale tidal stream energy potential of Midcoast Maine

In the State of Maine, USA, tidal stream energy resources over a large swath of coastline have remained largely under-evaluated. Former resource assessments have traditionally focused on spatially broad, high-energy areas in the region, such as the Western Passage, that show good potential for grid-scale energy contributions on the order of 10-100 MW. Localized energy hotspots of smaller spatial scales (e.g., 1-2 km 2 ) and “community-scale” extractable energy potential (order 1 MW) have been identified elsewhere in the State but largely omitted from regional assessments due to their considerably reduced energy footprints. In this work, we build and validate a high-resolution numerical model of the Maine coast to simulate tidal stream energy extraction within several of these under-evaluated hotspots in the Midcoast region of the state and outline the non-negligible community-scale energy potential of the area. Five hotspots are identified based on section-averaged kinetic energy fluxes ( KEF ). We then simulate energy extraction with two types of tidal turbines: one bottom-mounted, and another deployed near surface, in multiple array configurations to estimate a realistic range of extractable energy, via the annual energy production ( AEP ). AEP , when summed over each array, varies from 30 to 1120 MWh/year, depending on location, number of turbines which can be realistically sited in each array location, and turbine type. When considering the annual energy needs of surrounding municipalities, we estimate that 0.3% to 69% of the individual energy needs of nearby towns can be met by the individual adjacent hotspots. The impact of each array on local hydrodynamics and pertinent ecology is also considered and discussed.