The Federal Energy Regulatory Commission on March 20 issued a 10-year pilot license to Public Utility District No. 1 of Snohomish County for the proposed Admiralty Inlet Pilot Tidal Project to be located in the Puget Sound in the state of Washington.
The 600-kW Admiralty Inlet Project is an experimental project designed to determine whether commercial development of the tidal energy resources of Puget Sound is commercially viable. The March 20 action authorizes Public Utility District No. 1 of Snohomish County to study, monitor, and evaluate the environmental, economic, and cultural effects of hydrokinetic energy.
“The Admiralty Inlet Project is an innovative attempt to harness previously untapped energy resources,” said Acting FERC Chairman Cheryl LaFleur. “I look forward to the results of the experimental project and congratulate Snohomish for undertaking it.”
In issuing the license, FERC said it carefully considered the effect the Admiralty Inlet Project would have on sections of an under-sea fiber optic communication cable between the United States and Japan. FERC concluded that, with appropriate safety measures, the Admiralty Inlet Project would not pose a risk to the cable.
The pilot license contains measures to protect fish, wildlife, cultural and aesthetic resources, navigation and existing infrastructure. The license also contains several monitoring and adaptive management requirements to adequately protect against any adverse impacts from the project.
The project includes: two approximately 19.2-foot-high, 300-kW OpenHydro tidal turbines (Turbine 1 and Turbine 2) each mounted on a triangular subsea base; adaptable monitoring devices attached to each turbine base; two approximately 7,000-foot-long, 4-kV trunk cables, extending from each turbine to an onshore cable termination vault; an approximately 3.9-foot-long, 5.8-foot-wide, 2.9-foot-high onshore cable termination vault; two 40-foot-long conduits to convey the cables from the cable termination vault to a cable control building; a 24-foot-wide, 30-foot-long onshore cable control building to house power and monitoring equipment; a 17.2-kV step-up transformer located adjacent to the cable control building; and a 10-foot-long, buried 7.2-kV transmission line from the transformer to a connection with Puget Sound Energy’s system.
The project will be located in Admiralty Inlet in the northwestern portion of Puget Sound between the Olympic Peninsula and Whidbey Island where the northwestern end of Puget Sound meets the Strait of Juan de Fuca. Its cable control building will be located on Whidbey Island near Fort Casey State Park. The turbines will be placed approximately one kilometer west-southwest from the shoreline of the state park (Admiralty Head) at a water depth of about 58 meters. Peak tidal currents in this area exceed three meters per second.
The project’s OpenHydro System is designed to generate electricity over a range of water flow velocities, within a stationary turbine frame, but with the turbines turning in both ebb and flood tides. The turbines will convert the kinetic energy of water flowing in current from 0.7 meters per second to 3.3 meters per second into rotational motion and deliver that energy through the rotors into the generators. The turbines are expected to rotate about 70% of the time.