Snohomish County Public Utility District will work with OpenHydro, an Irish technology company, to design, build and install up to three marine turbines at a tidal energy pilot plant in Admiralty Inlet west of Whidbey Island.

The pilot project, expected to begin operation as early as 2011, will produce up to one megawatt of energy, enough to serve about 700 homes. The tidal devices will be connected to an undersea electrical cable and fed to existing transmission lines near the Keystone Ferry terminal on Whidbey Island.

The PUD will place up to three horizontal axis tidal devices on the seabed floor approximately one kilometer west of Admiralty Head. Installation of the turbines will not require any drilling or piling operations on the seabed. The turbines will be positioned outside of the main shipping channel and ferry routes, will be completely submerged, and will allow for over 80 feet of overhead navigational clearance. The tidal generators measure 50 feet in height and can spin either way depending on the direction of the tides. No oils or lubricants are required for operation.

Videotaped monitoring of a similar operation in Scotland has indicated no impact on fish and marine mammals in a region that is prized for its ecological diversity. The turbine design has no exposed blade tips and includes a significant opening at its center to allow unimpeded passage of marine life.

PUD general manager Steve Klein said of the project, "Tidal energy can be sited right here in Western Washington and easily integrated into our existing electrical system without requiring hundreds of miles of new transmission lines."

"OpenHydro's vision is to develop arrays of tidal turbines, silently and invisibly generating renewable energy under the world's oceans," said James Ives, chief executive of OpenHydro. "We believe that tidal energy has the potential to make a considerable contribution towards meeting the PUD's 2020 renewable energy targets."

In the next two years, the PUD will focus on finalizing its engineering plans and obtaining permits from the Federal Energy Regulatory Commission and other state and federal agencies. In addition, it will conduct a series of studies to better assess tidal flows, seabed composition, fish and marine mammal presence, cable routes, interconnection options and a range of other issues.

During the pilot project, the PUD will conduct in-water testing and monitoring to address issues related to tidal turbine performance, cost and environmental effects.

OpenHydro cites several advantages of generating electricity using its Open-Centre turbine technology including:

The electricity produced is completely renewable since it relies on tidal currents that are created by the gravitational effect of the sun and moon on the world's oceans.

Whereas other forms of renewable energy are dependent on the weather conditions (such as the amount of wind or a clear sky), tidal energy is completely predictable, giving the electricity produced a premium value.

Since the turbines are located beneath the surface, they are protected from storm damage and cannot be seen or heard.

Due to the density of water, a relatively small turbine can produce the same power as a much larger wind turbine.

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