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Marine Energy: Harvesting Power from Nature

Marine Mammals and Fish Befriend Offshore Turbines

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Conditions off the coast of Virginia are ideal for construction of offshore wind turbines, but scientists see a limited role for marine energy – power generated from waves, currents and tides. 

That’s because prevailing winds on the planet blow from west to east, creating bigger waves on the west coast of continents.  Still there is some potential here, and experts say turbines can likely be placed off our shores with minimal risk to wildlife.

Since she left home in Roanoke to study marine biology, Sarah Henkel has been looking at the possible impact wind and water turbines could have on whales and dolphins, fish and birds.  Now an assistant professor at the Hatfield Marine Science Center at Oregon State University, she believes wildlife could be a bigger problem for the turbines than the turbines are for them. 

Just ask the sea lions that lounge along Oregon’s coast.

“Sea lions love to haul out on buoys.  They love it, and so there’s a lot of engineering and design going into how do you shape this or coat this with Teflon so that a sea lion can’t hang out on it, because it would definitely affect the performance of an engineer-generating device if a sea lion was sitting on it.” 

Her colleague, Oregon State  Professor Ted Brecken, agrees.

“You know you can imagine that if you have a wave energy converter that’s well designed to operate in a very particular way, it might behave a little differently if it’s got a couple thousand pounds of sea lions on it.”

Other marine mammals could become tangled in lines that hold water turbines in place, but Henkel says collisions are unlikely.  Birds that crash into land-based turbines may be flying 50 miles an hour, but ocean creatures move much more slowly.

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Oregon State Researchers

“Gray whales aren’t zipping around, so we think they have the wherewithal to avoid these kinds of things, but it’s definitely something that’s worth looking into, and if parks ever get large, and the whales prefer to go around them as they migrate, that could add length to their migration time.  Some species don’t feed the entire time they’re migrating, so if they have to go an extra day without feeding, it could be a little hard on them.”

Now it’s true that noise could be a problem for some ocean residents, according to biologist Gareth Davies.  From a base in Scotland, he consults energy companies in 20 countries.

“There are instances of where whales and dolphins and seals, and indeed, fish have been shown to react to persistent and loud sources of noise.  The oil and gas industry undertakes seismic surveys – which are one of the loudest noises that man gives rise to in the sea.  Large shipping also can cause avoidance behavior.  The level of noise that supertankers generate is far, far greater than any of the noise from the renewable energy devices.”

And he says existing energy sources are a bigger threat to wildlife with oil spills fouling their waters, coal and gas polluting the air, and excess carbon-dioxide in the atmosphere causing the oceans to acidify.  That’s why he hopes to see marine energy evolving in North America.

“It’s really worthwhile looking at the assets you’ve got locally – thinking about whether Virginia produces energy in other forms, and if it doesn’t, what would happen to Virginia if it started to produce some of its own energy.  It’s not just the energy itself.  It’s about the jobs and the self-reliance that it brings -- getting experience that you can share with other people in other parts of the world.” 

In truth, our waves are too small and the expense too great to make marine energy viable in Virginia, but someday it may be.  Virginia Tech Professor George Hagerman thinks it will make sense to harvest wave power once we have wind turbines offshore.

“You’ve already got the cable infrastructure out there.  You’ve already got the  environmental permitting.  It’s already a known spot in the ocean to be avoided by ships and other users. It could enhance the value of offshore wind on the east coast.”

And there’s a Virginia company that could make it happen, once they’ve installed commercial wave farms in Europe.  We’ll profile that enterprise in our next report.  

Sandy Hausman reported from Europe with the support of an Energy and Climate Media Fellowship from the Heinrich Böll Foundation.

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