AD Main Menu

Could the ocean's whopping tides help power Alaska?

Hannah HeimbuchThe Arctic Sounder
Loren Holmes photo

As energy companies race to reap the benefits of Arctic oil, other parts of Alaska are charging into new energy technologies. In False Pass, researchers have initiated a project that explores the potential power of ocean currents.

Much like wind turbines harness the massive moving energy of air currents, underwater turbines lasso the energy created by water currents. Alaska is lacking in neither natural phenomenon, said scientist Bruce Wright.

Wright is the senior scientist for the Aleutian Pribilof Islands Association, an Aleut tribal nonprofit. The organization recently received a $200,000 U.S. Energy Department grant to explore tidal energies, and its focusing its attention at the narrow saltwater chute of Isanotski Strait at False Pass, at the end of the Alaska Peninsula. It is the first pass that Pacific waters come to as the Alaska coastal current pushes them toward the Arctic Ocean, Wright said.

Alaska possesses 90 percent of the United State’s total tidal power potential, according to the Ocean Renewable Power Co., the company contracted to conduct the research at False Pass. ORPC is also conducting similar research in Cook Inlet, as well as other locations around the country.

Recently, two acoustic current Doppler profilers were placed in the waters of False Pass, and will remain there for about five weeks, Wright said, collecting data on the volume and speed of water moving through. There are two forces at work in coastal waters, Wright said, the Alaska coastal current and the daily tides.

“There’s a Coriolis effect which is caused by the spinning of the earth on its axis,” Wright said.

The earth’s rotation naturally pumps water out between Canada and Greenland and down into the northern Atlantic Ocean.

“To make up for that vacuum that’s created in the Arctic Ocean, water from the Pacific fills that, coming up along the Alaska coast. The Alaska coastal current starts along the coast around British Columbia, and propagates up.”

The velocity with which that massive current moves is in part determined by how much fresh water is streaming out of Alaska’s coastal mountain range and into the ocean. That outflow is about 1.2 times the size of the Mississippi River’s.

What Wright and the Ocean Renewable Power Company want to know is, how much force is generated as this current pushes past land formations, like at False Pass, and how well can it be harnessed by underwater turbines.

A speed of about seven knots is prime, Wright said, and not terribly uncommon along coastal Alaska. Their research will include several elements, Wright said. First, they will examine the power grid at False Pass to determine how much power the community uses, and how equipped it is to handle power efficiently.

The next part, which began last week when the profilers went underwater, is to determine exactly what kind of power output could be available by harnessing the local waters.

The University of Alaska Anchorage engineering department helped by establishing optimum spots to put the profilers, using historical tidal and current data.

“When I proposed this project I wanted to capture that Alaska coastal current,” Wright said. He wanted to know "if it was strong enough to drive a turbine. In addition to the ocean current going through False Pass there is also a tidal influence, caused by the gravity of the moon and the sun.”

Wright and others want to know how much this tidal influence affects the power of the current. This is one reason they are conducting at least a full month of data collection -- to observe an entire lunar cycle of tides.

“So there’s a question then, how strong is the Alaska coastal current and how does it correspond, dovetail, counteract or relate to the tidal current?” he said.

Should they find a viable amount of power, a number of things will need to happen before False Pass can be plugged in.

They will need to explore the permitting process, Wright said, as well as conduct environmental work to ensure their project and product are environmentally safe. However, that’s one of the things Wright likes about this project’s potential, its low impact in many environmental aspects.

“What is appealing to me is that they’re geared to run at low speed,” Wright said. Wind turbines have to run at very high speeds to generate power, but water, being 200 times denser, allows turbines to rotate more slowly.

“Animals moving through the water can avoid these things or even swim through them,” Wright said, adding that tests for the equipment they are using now verify that. “We’re also real excited about deploying during October,” he said. “The period between late September and early December is when you have your big fall tides.”

After their data collection period is done, Wright and his team will spend the winter analyzing data and coming up with the next step.

“I’m pretty excited about the project because of the potential it means for Alaska, especially these remote communities,” Wright said. “If we can provide half of the electricity and half of the heat for False Pass, why can’t we do that in all of our coastal communities?”

Or for that matter, Wright said, for larger cities as well.

This story first appeared in The Bristol Bay Times. Hannah Heimbuch can be reached at hheimbuch@reportalaska.com.