The Tacoma Narrows Tidal Power Feasibility Study was conducted to determine if Tacoma Power could generate commercial-scale, cost-competitive renewable power from the energy of marine tidal currents in the Tacoma Narrows of Puget Sound, Washington. Tacoma Power envisions a four-phase investigation. In Phase I, completed in 2005-2006, the Electric Power Research Institute (EPRI) did a “bench” study and concluded that an array of 64 large double-rotor tidal turbines could generate about 16MW of power at a site in Tacoma Narrows. EPRI concluded that the Cost of Energy would be competitive but it was not able to include costs for environmental permitting and regulation and studies.
In Phase II, this Study, a team of leading Northwest oceanographers, marine technology experts and firms, environmental and regulatory experts and economists used new field data and advanced modeling to determine the actual power available. The tidal turbine technology available was surveyed and evaluated for its application to the site. Studies and permits were estimated and economics considered.
Phase III would be a pilot project to demonstrate a few tidal turbines in the Narrows, following approval by authorities. Phase IV would be the commercial array.
Commercial-scale tidal power generation in Tacoma Narrows does not appear feasible for at least another eight to ten years. The amount of power that could be generated is small compared to Tacoma Power’s needs. Under existing economic conditions commercial-scale tidal power generation is not economically competitive compared to other resources such as wind power.
However, over eight or ten years, conditions will change and Tacoma Power may want to develop the resource. To preserve its permit and license options for the site, Tacoma Power should renew its preliminary permit in 2009 and apply for a five year pilot project license and project that would be funded by third parties. By the time a pilot project is completed there may be advances in tidal turbine technology that increase power and
decrease costs and impacts to the point that the project is economically desirable and environmentally feasible.