Admiralty Inlet dubbed ideal for pilot tidal-power turbine project

Nearly two years of monitoring show the Admiralty Inlet is an ideal place to harness tidal energy, University of Washington researchers say.

UW oceanographer Jim Thomson said researchers have measured currents of up to 8 knots, or 9 miles per hour, faster than initially expected. He said data collected so far also show the site, the water separating Whidbey Island and the northeast corner of the Olympic Peninsula, isn't used much by marine species.

The Snohomish County Public Utility District (PUD) wants to put two large turbines about 200 feet below the surface of Puget Sound.

UW researchers have been monitoring water speed, ambient noise and water quality at the site.

The pilot project would generate 100 kilowatts of electricity, or enough to power between 50 to 100 homes.

"We think it's a good site, and we think it's the right place to do a pilot project," said Thomson, who is also a UW assistant professor of civil and environmental engineering.

The school has been working with the public utility to find a good spot for two 30-foot turbines that will likely be installed by the PUD in late 2013.

Brian Polagye, a UW research assistant professor of mechanical engineering, presented recent findings at the American Geophysical Union's annual meeting Monday in San Francisco.

He and his colleagues have been studying the physical attributes of the site, including the noise and currents. They also will monitor the environmental effects of the turbines once they're installed in the water.

"The results of this pilot project will help decide if this is an industry that has potential for going forward at the commercial scale, or if it stops at the pilot stage," Polagye said.

One issue is how the turbines may affect marine mammals, particularly endangered killer whales.

So far, it appears that orcas don't hang out in the area but tend to move through the channel closer to the surface, Thomson said.

"At this point, the good news is that there are no show stoppers," he said. "We haven't found a lot of use of marine species in the area. We haven't found anything that would really be a red flag."

Craig Collar, the PUD's energy-resource development manager, said the PUD is planning to submit a license application to the Federal Energy Regulatory Commission early next year.

More work is being done to understand how the turbines would affect marine life.

Researchers are also trying to better understand how underwater noise from the turbines could affect marine mammals that use sound to navigate.

Thomson said it was surprising to learn how loud the site already is from shipping vessels and ferries.