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Solving mysteries of water power
by MARK ST.J. COUHIG
Aquatic sources of power — waves, tides and currents — are expected to play a large role in meeting America’s future power needs.
First, however, someone has to figure out how to gather that power efficiently and safely, and with as little environmental impact on the oceans and rivers as possible.
The U.S. Department of Energy has asked Pacific Northwest National Laboratory (PNNL) to do just that and is paying $3.45 million for the necessary research. The lab now is completing its second year of investigations into the environmental impact of water power production, work that includes field tests in Sequim Bay.
The Sequim connection
Much of the research is being conducted at PNNL’s Marine Sciences Lab in Sequim, where lab workers are determining the long-term impact of full-scale water power — also called hydrokinetic — installations.
They are particularly interested in investigating how fish and marine mammals are affected by several aspects of hydrokinetic generators, especially noise, electromagnetic fields and the possibility of “blade strikes.”
They also are looking into whether the devices could create “dead zones” by interfering with the ocean’s circulation and nutrient patterns.
Andrea Copping, a senior program manager with PNNL, points out that humans have been creating electromagnetic fields (EMF) in the oceans for a hundred years, primarily by laying cable along the sea floor. Unfortunately, the collected research on the impact is slender, she said. At the Sequim lab they’re now “challenging” organisms to get a better handle on the impact.
Much of the work is done in two tanks in a back room in a seaside lab. Each tank has a large electromagnetic coil — painted a brilliant red — looped around it.
Test organisms, including halibut and Dungeness crab, are placed in the tanks, the EMF is cranked up and the behavior of the test subjects is studied.
The lab soon will bring in American lobsters, which as Copping points out, play a big role in the economies of several northeastern states.
“Next year we’ll try sharks, too,” Copping said, noting sharks already are known to be highly sensitive to electrical fields.
The purpose of the tests isn’t just to discover whether the animals are attracted or repelled by an electromagnetic field. The researchers also are looking for more subtle neurological effects, Copping said, which may cause very subtle changes in behavior.
Sequim researchers also are broadcasting into a large tank the recorded sounds of existing underwater turbines to measure the impact of the noise on fish. Copping said they are particularly concerned about the impact of the sound on marine mammals, but said it is almost impossible under current regulatory regimes to “challenge” mammals, which are protected by law from “harassment.”
“Fortunately,” Copping said, “fish ears develop like mammals’. It’s not that big a stretch” to infer the impact on marine mammals, she said.
Blade strikes are a problem, Copping said, because screens, which appear to be the common sense solution, significantly reduce water flow through the generator, thus significantly reducing power.
Finally, she said, the lab is working on modeling the impact of generators on water flows. “How many can you put in before you have a problem?” she said.
Copping said a large part of their effort isn’t targeted toward the science underlying hydrokinetic power generation, but rather toward the regulatory hurdles that face anyone who hopes to utilize new forms of water power.
Copping said “there are so many agencies” that would be required to be involved, including federal, state and local regulators.
The issue is further confused because the environmental impacts derive from a wide range of sources, with Copping pointing out as an example that the generators’ “anti-fouling coatings ... are toxic by nature.”
She said the introduction of the generators also presents a “new use of ocean space.”
“How does that affect commercial and recreational fishing?” she asked.
To make matters even more difficult, there is no standard design for water-power generators. While most wind-powered turbines are now three-bladed, there are 40 to 50 different designs for ocean turbines and more can be expected as the technology becomes more financially feasible.
She said it’s vital to the future of the industry to complete the research. The National Oceanic and Atmospheric Administration has stated flatly that no turbines will be installed without proof that wildlife will be protected.
The research in Sequim has national and international importance but its first impact may be felt locally.
Snohomish County Public Utility District’s tidal energy research project recently received $10 million in funding from the U.S. Department of Energy to support a pilot project in which two “OpenHydro” turbines will be deployed in Admiralty Inlet west of Whidbey Island.
If all goes well, before those turbines are installed Sequim’s Marine Sciences Lab will have the data in hand to ensure they have the least possible environmental impact on the area’s shared waters.
Reach Mark Couhig at email@example.com.