As relentless as the tides they are trying to harness, Snohomish County PUD officials are pushing ahead with their dream of growing into a world leader in the development of tidal energy.

The utility on Thursday filed key documents with federal regulators to begin testing tidal turbines at Admiralty Inlet by the end of 2010. If those tests are successful, the utility could eventually put as many as 1,662 turbines in the water. The turbines could generate enough electricity for 70,000 homes.

The PUD has finished the first year of a three-year study to see if it makes sense to plant fields of the windmill-like turbines at as many as seven locations around Puget Sound, including at Admiralty Inlet. The filing with the Federal Energy Regulatory Commission updates the utility’s progress so far and also sets the table for discussions on the potential environmental effects of tidal turbines on Puget Sound.

“I would say we are encouraged, but there is still a long way to go,” said Craig Collar, senior manager of energy resources development at the PUD. “We have not encountered anything that we would say is a roadblock. No deal breakers.”

Called a “pre-application,” the filing with FERC is the first ever for a tidal energy project in the United States, Collar said. Although there are several tidal studies under way across the country, including one in Tacoma, none are as far along as the PUD’s, he said.

In its Thursday filing, the utility laid out a number of studies it must complete to make sure the turbines don’t harm endangered orca, salmon and other marine wildlife. They include: assessing the chances of fish and other marine wildlife hitting a turbine, finding out whether the many ocean-going ships that travel through Admiralty Inlet will have to be rerouted, gauging the impact turbine noise would have on marine life, and sorting out whether treaty rights of area American Indian tribes would be violated.

Members of the environmental community have been waiting for some of those studies to be done before taking a position on tidal power and the PUD’s venture. Many of the groups do have concerns.

“We need to see how it might affect us,” said Daryl Williams, environmental liaison for the Tulalip Tribes. “We’ve lost a lot of fishing areas in Puget Sound over the last 150 years. Our fishermen don’t like losing new areas.”

The biggest concern is whether tidal turbines, especially when developed as fields as the PUD hopes, could keep fish from heading through Admiralty Inlet, Williams said.

“Every fish in Puget Sound is going to be swimming through that area,” he said.

Admiralty Inlet is where Puget Sound meets the Strait of Juan de Fuca.

Tribes in north Puget Sound plan to meet Tuesday to discuss how they want to respond to the PUD report, Williams said. He said his tribe’s tribal council also wants to review the matter.

Orca also use Admiralty Inlet to enter Puget Sound from the Pacific Ocean during the winter months, said Fred Fellman, a Northwest consultant for Friends of the Earth.

“To me, it comes to a matter of scale,” Fellman said. “I’ll be open-minded enough to look at one to see what power it generates, run a video to see what biological impacts it has.”

He is worried that scaling up the project to anything larger than a few turbines could have devastating impacts on an ecosystem that’s already pushed to its limits, he said.

Collar said the utility is focused on trial study that would involve a handful of turbines. The project only would be expanded if the PUD can prove that doing so won’t cause harm, he said.

“Clearly there’s good reason to be concerned about Puget Sound,” Collar said. “We want to contribute (to helping restore it). We’re not going to do anything to make things worse.”

Reporter Lukas Velush: 425-339-3449 or lvelush@heraldnet.com.