Tidal power plan in works

Feb. 25, 2007

By Russell Stigall

Frontiersman

MAT-SU - The tides will turn in Knik Arm. And they will turn electric generators if Chris Sauer, president and CEO of Ocean Renewable Power Company proves his prototype turbine.

In as little at three and a half years, Ocean Renewable could have a commercial power plant installed in Knik Arm between Port MacKenzie and the Port of Anchorage.

Sauer said his tidal generators, called OCGen modules, could produce electricity in the tens of megawatts - enough electricity to power thousands of homes in the Mat-Su Valley.

“Cook Inlet has tremendous potential,” said Sauer, whose company is developing a sister tidal project in Maine's Western Passage.

Tide-power generators work like wind turbines. As tides rush in and out, water flows over the turbine blades, causing lift like an airplane wing. The lift pulls turbine blades around and spins a generator. Since tidal turbines are similar to wind-powered generators, tidal generators have been able to borrow from years of wind-power research.

There are, however, differences between tidal power and wind power. Tidal power is predictable. Also, since water is 1,000 times more dense than air, it provides more torque.

Three 10-foot-by-48-foot OCGen modules can produce the same power as a wind 236-foot diameter wind turbine mounted on a 230-foot tall tower - a structure roughly the size of a 747 aircraft. Also, hidden underwater, tidal generators do not affect the visible landscape.

The project will start with a year-long test of Ocean Renewable's prototype OCGen module. Sauer said his company looked at possible sites in Southeast Alaska, Cook Inlet and Resurrection Bay near Seward. Ocean Renewable chose the area of Knik Arm just off Port Mac as its test site due to the arm's fast tidal currents - in excess of 6 knots - and proximity to electrical grid and port facilities.

“We're hoping to actually get his thing in the water in less than two years,” Sauer said.

Sauer said the prototype will help find the effects of an OCGen module on its surroundings. “The environmental community have their concerns, which they should,” Sauer said. “None of us know absolutely at this point if there are any issues. This prototype will help us determine this.”

The year-long test will monitor the prototype's efficiency and its effect on fish, Beluga whales and overall tidal flow.

Marc Van Dongen, port director at Port McKenzie, said Port Mac makes an ideal location for Ocean Renewable's test for varied reasons. Cook Inlet has the second largest tides in the world, and Knik Arm has the fastest tides in Cook Inlet, Van Dongen said.

“And we're at the narrowest part of Cook Inlet, at Cairn Point,” he said.

Knik Arm is deep, too.

“We have 60 feet of water at low tide, so (Ocean Renewable) could get their test module down below the ice.”

And the port has the infrastructure, including a crane for moving modules in and out of the water, to make Sauer's test convenient. The port also has docking facilities for test vessels and uplands for module construction.

Ocean Renewable may also have much to offer Port Mac.

Van Dongen is looking past the test to the possibility Ocean Renewable will build a full-scale commercial generator at Cairn Point. Commercial production could allow fabrication of the modules on leased uplands at Port Mac, providing jobs.

“And creating jobs, that's what we are trying to make happen,” Van Dongen said.

Port Mac's current power supply should fuel the estimated growth in the area for about eight to 10 years, Van Dongen said.

A commercial tidal generator would be a natural and non-polluting source to power Port Mac's growth, Van Dongen said.

Van Dongen said he believes in the concept and is optimistic Sauer will get the permits he needs to run the test module.

The port is drafting a memorandum of agreement with Ocean Renewable, and if Borough Manager John Duffy signs off on it, the port will advance its relationship with Sauer's company. The borough won't fund the project, though.

“We're just trying to work with a company that is doing something that makes sense to us,” Van Dongen said.

Van Dongen said he has yet to get Matanuska Electric Association interested in the tidal generation project.

“I've called them half a dozen times since Christmas,” Van Dongen said. Without a reply.

Sauer said to test and monitor his prototype for a year will cost about $8 million to $9 million. He has approached private investors, the Denali Commission and the Alaska Energy Authority for funding.

Sauer said the estimated cost of a 20 megawatt commercial plant would be $36 to $38 million. It would produce power at about 6 to 10 cents per kilowatt-hour - about the same as MEA's planned coal-fired power plant, without adjustment for pollution-control costs.

However, other savings will come from tidal power being a renewable, non-emission technology. For more information, interested people should point their Web browsers to www.epri.com or www.oceanrenewablepower.com.

Contact Russell Stigall at

352-2267 or russell.stigall@ frontiersman.com