Testing begins for tidal energy at Deception Pass

The Snohomish County Public Utility District will begin testing Deception Pass in August to determine its viability as a source of tidal energy.

The utility district has placed itself at the forefront of tidal power research through its studies. The PUD has filed applications to study seven locations in and around Puget Sound — from Deception Pass to Speiden Channel in the northern San Juan Islands. The seven sites combined could provide as much as 100 average-megawatts of energy, or enough power for about 60,000 homes. The projected megawatt production was a conservative estimate based on historical data from the National Oceanic and Atmospheric Administration.

Energy would be created by using the naturally occurring tidal currents to drive energy conversion devices attached to the seabed. The devices would be completely submerged, without dams or barrages, and would not be visible from the surface. Sub-C power conduits could be extended from the device through a trench in the seabed or directly on the seabed with a covering, said Craig Collar, Snohomish PUD senior manager of energy resource development.

Ashore, directional drilling will allow the cable to come in under the shoreline and emerge a distance away, fed into the equivalent of a small substation.

“That’s really our vision,” Collar said. “For all intents and purposes, it needs to be invisible when you’re looking at the water and the shoreline.”

Consultants will begin performing two versions of acoustic Doppler profiling at Admiralty Inlet this month to measure the actual currents. The “over-the-side” profiling conducted on a boat will transect through the water and analyze the currents. One stationary unit will sit on the seabed and over the course of a month record the current’s velocity.

Deception Pass will be examined in August.

“We haven’t nailed down the dates yet,” Collar said.

He added that four profiling units could be used next year.

“This is just the start,” he said.

The narrow channel south of Pass Island has been identified as the optimal area for testing at Deception Pass. Collar and Neil Neroutsos, Snohomish PUD spokesperson, visited the area Friday. If the tests reveal too much swirling and too many eddies, the turbulence would make using the site unfeasible.

“If that’s the case, then we move on and we don’t look at that site anymore,” Collar said.

Rivers are also being studied for their hydropower potential, but the PUD is not currently looking into the possibility.

The tidal energy applications were filed in June of 2006 at the Federal Energy Regulatory Commission. All seven permits were received as of March 9, 2007.

The FERC permits would not authorize construction, nor has the PUD made any commitment to construct tidal facilities. Rather, the permits would allow the utility to apply for construction permits in the future. The PUD will only consider moving forward on a tidal project once studies have confirmed both the technical and economic viability, and is convinced that the project can be executed in an environmentally responsible manner.

The utility is particularly interested in collaborating during the studies with other stakeholders who share the PUD’s interest in the responsible stewardship of the Puget Sound ecosystem.

The series of studies is being funded in part by a $220,000 grant from the Bonneville Power Association. The testing will include onsite computer modeling with the University of Washington, the assessment of environmental impacts and regulatory issues or requirements.

All of the data will be crucial if the PUD moves into the pilot phase, which would happen at the end of the three-year studies. Collar said they are currently three or four months into the studies.

The acoustic Doppler profiling this summer will create “new to the world” data, Collar said, which will be used along with historical data on the currents and information regarding the quantifiable physical conditions of the seabed.

PUD representatives have been working feverishly on outreach, meeting with stakeholders and describing the proposed projects. Once the first phase of the studies are finished, the public outreach will be ramped up in late fall with informal open houses.

“We can anticipate the types of questions people have,” Collar said. “We want to be able to answer them.”

One question will undoubtedly be the issue of maintenance. How does one work on a wire buried underneath the seabed? Very carefully.

“Folks are looking at how to make these economically maintainable,” Collar said Friday during the site visit.

Tidal power, despite aggressive conservation programs, has become a viable consideration as the demand for electricity in the Puget Sound area has grown.

“The PUD and other utilities recognize that the Northwest region and the entire nation need to find new, environmentally-friendly, renewable sources of energy to meet this growing demand,” said PUD General Manager Steve Klein in a press release.

Additionally, the recently passed Initiative-937 will require the PUD to meet 15 percent of its load with renewable resources, not including traditional hydropower, by 2020.

The PUD hopes that the Northwest can become a leader in the emerging ocean energy industry. Northwest tidal research could serve as a model for other U.S. tidal sites.

You can reach News-Times reporter Paul Boring at pboring or call 675-6611.

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