7/12/2006 10:50:00 AM Admiralty Inlet one site for tidal power turbines
Snohomish County PUD officials have filed a preliminary application to study the possibility of installing underwater generators powered by the tides in this section of Admiralty Inlet, shown in the shaded area on the map. – Graphic illustration by Marian Roh
The sea floor off Point Wilson is being eyed as the potential site for 450 turbines that would use the forceful tides there to generate electricity for what could eventually be one of the first tidal power projects in the United States.
The field of generators – called Tidal In-Stream Energy Conversion (TISEC) devices – would produce the bulk of electricity for an underwater Snohomish County Public Utility District plant that officials there hope to install throughout Puget Sound.
Snohomish PUD describes in its application windmill-like devices with propeller blades 20 meters in diameter. They would be anchored to the ocean floor, and the moving action of the tides would spin the blades to produce electricity.
The project is still in an early planning phase, and Snohomish County PUD is “not committed to constructing anything at the moment,” said Jeff Kallstrom, an attorney for the organization.
Snohomish County PUD has applied to the Federal Energy Regulatory Commission (FERC) for a three-year permit to study the group of sites – which also includes Deception Pass and Agate Passage – and install some test TISEC devices.
Cutting edge technology
While the tides have been looked to for years as a potential renewable energy source, technology to harness their power is still in its infancy, according to the California-based Electric Power Research Institute (EPRI), an organization at the forefront of tidal power research.
One recent EPRI report puts current tidal power technologies “at the stage of development that wind power was at 25 years ago.”
The turbine that Snohomish PUD describes in its application is similar to a prototype developed by Verdant Power, a company installing six TISEC units for a trial run in New York’s East River.
Verdant co-founder and President Trey Taylor said it’s been a lengthy process.
“We began working with the local community to build this test pilot project, and we’ve been at it almost five years now,” Taylor said.
Taylor said the turbines spin at about 32 rpm – slow enough for fish and other marine life to swim out of the way. Still, they’re installing six “hydroacoustic transducers” that will monitor how fish negotiate each one of the turbines. Taylor anticipates very little environmental impact. But if there is an adverse impact, the turbines can be quickly removed.
“These can come out of the water faster than they actually go into the water, so if you run into some environmental issue that you hadn’t anticipated, you can just pull them out of the water,” Taylor said.
Reducing environmental impact is the aim of dam-less – or kinetic – hydropower. Taylor, also the chairman of the Research and Development Committee of the National Hydropower Association, said kinetic hydropower could be interfaced with solar and wind energy plants to produce large amounts of “green” energy.
“This could be a whole new way of looking at new energy generation,” Taylor said, and ultimately produce a large amount of new energy.
He said some commercial developers have also started to think that way and are filing preliminary permits with FERC in an effort to get their hands on the best tidal energy locations.
“Many of us suspect that it’s sort of a land grab, sort of like the early days of [Internet] URLs,” Taylor said.
Snohomish PUD does not fall into that category, he said. For the PUD, the proximity makes it a practical location to extract renewable energy.
PUD Manager Klein said that’s precisely why PUD officials looked toward Puget Sound when searching for a renewable, sustainable power source for their growing customer base in Snohomish County. Wind power, he said, would have taken them to Eastern Washington.
“These sites are in our backyard,” Klein said. “We could integrate directly into our distribution system rather than having to construct miles and miles and miles of transmission through the Cascade Mountains.”
The sites are also in Jefferson County’s backyard. Still, County Administrator John Fischbach said he had not been made aware of the proposal, nor had Fort Worden State Park Manager Kate Burke.
Klein said the devices off Point Wilson would be completely submerged and that fish and marine mammals could easily avoid them.
He said they would have no effect on boating through the inlet.
At the high end, they speculate that the field of 450 turbines in Admiralty Inlet would produce 146.2 gigawatt hours per year – enough electricity to fully supply 10 percent of Snohomish County’s more than 600,000 residents. Combined, the other turbine fields proposed for Puget Sound would fill 3 percent of Snohomish County’s current power need, they said.
Klein pointed out that Snohomish County is among the fastest growing areas in the state and that by the time the turbines are up and running – he guessed about eight years from now, if everything works out – the county’s power need could be much higher than it is now.
“We could grow 50,000 to 60,000 customers over the next five to seven years,” Klein said.
The devices would harness between 10 and 20 percent of the force of the tidal flow – the maximum amount currently recommended by EPRI.
EPRI researcher Bryan Polayge, a pre-doctoral candidate at the University of Washington, said that figure was derived from preliminary research by British scientists and that it could be raised.
“That question, I think, still remains to be answered,” Polayge said. “Maybe 30 or 40 percent could be extracted.”
Not commercial yet
While there is widespread interest in tidal energy and numerous private companies have emerged with prototypes in recent years, no tidal energy extractors have been developed at a commercial level, EPRI ocean energy leader Roger Bedard said.
“They are only being used for the purposes of at-sea development and testing,” Bedard said. “There are no commercial plants yet.”
Bedard mentioned Verdant’s East River project and an experimental unit that’s been operating in the United Kingdom for about three years.
While it is a cutting-edge technology, Bedard said it would never completely solve the problem of finding renewable energy.
“I don’t believe there’s any such thing as a prime energy source for the future. I don’t believe there’s a silver bullet,” he said, adding that it would take a combination of technologies. “We need to have a diversified and balanced mix.”
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