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Published on January 15th, 2017 | by Tina Casey


Wind Energy Lab Puts The Heat On US Navy’s StingRAY

January 15th, 2017 by  

The National Wind Technology Center is putting a wave energy converter through a months-long series of mechanical and electrical tests, and if that seems like someone got their renewable energy technologies mixed up, guess again. The wave device, dubbed StingRAY, shares a key design concept with wind turbines.

Wave Energy for the US Navy…Eventually

StingRAY is a project of the company Columbia Power Technologies. It began to take shape in 2014 with the help of a $3 million assist from the US Navy, which has an obvious interest in marine renewable energy technologies.

A number of different types of wave-based devices are in development, and apparently the Navy sees quite a bit of promise in the StingRAY.

The StingRAY design takes advantage of the difference in movement between the “floats” that rest at the surface of the water, and the spar that hangs down beneath.

So far the Navy’s investment seems to be paying off. In March of last year, the StingRAY design received an all-important thumbs up from the international certification body DNV GL. Getting the okay from DNV GL effectively paved the way to develop a full scale prototype.

There are still a few more steps before that happens.

Last fall, Columbia delivered its prototype generator to the National Wind Technology Center, a division of the Energy Department’s National Renewable Energy Laboratory, for initial testing.

In the latest development, the lab has been deploying its wind testing equipment to mimic the motion of ocean waves. Here’s a brief explainer from Columbia CEO Reenst Lesemann…

The dynamometer can mimic the sea, with back-and-forth oscillation, and will put the generator through its paces to ensure it can withstand ocean forces.

…and here’s a slightly more enthusiastic portrayal from project Manager Mark McDade of the Wind Technology Center:

We have one of the only facilities in the country with a dynamometer that can apply rotational torque at the speeds and forces required while also applying non-torque loads-which are side forces that simulate the action of a rogue wave hitting a wave energy converter in the ocean. This matters because the structures of these energy conversion devices must be designed to handle the side forces without damage. The work is pioneering in the field of ocean energy conversion.

That’s more like it!

Once the mechanical part of the testing is out of the way, the Wind Technology Center will hook the StingRAY up to a grid interface to measure its electrical capabilities.

If all goes according to plan, later this year the generator will head up to Hawaii for testing in the open waters, at the Wave Energy Test Site located at Marine Corps Base Hawaii in Oahu.

Sometime in the sparkling green future, wave energy converters like the StingRAY may also get a chance for testing and development at a spanking new utility scale test site to be located off the coast of Oregon.

In a proposal advanced by the Obama Administration last December, the new site will dwarf the Hawaii facility. It will be built and operated under the auspices of Oregon State University’s Northwest National Marine Renewable Energy Center, with $40 in funding from the Energy Department.

That’s assuming there still is an Energy Department after President-elect Donald Trump takes office.

Onwards And Upwards For Wave Power

Meanwhile, Columbia has some other interesting news to report. The company has been working on something called an “autonomous, low-power wave energy system” for DARPA, the Defense Advanced Research Projects Agency.

The project is part of TUNA, the somewhat witty acronym for the agency’s Tactical Undersea Network Architecture program.

Here’s a rundown on the program from DARPA:

Small fiber optic cable systems performers are seeking to develop lightweight, buoyant unpowered optical fiber technologies capable of surviving deployment and operation in the ocean for at least 30 days. Buoy nodes performers are tasked to develop rapidly deployable buoy node designs and component technologies.

Got all that? The sticky wicket comes in when you have to figure out a way to supply power to the buoys. A buoy-based wave energy harvesting system is a perfect match.

Here’s a schematic of the system (check out YouTube to see the buoys in action):

wave energy DARPA

Earlier this month DARPA announced that initial tests have been completed, so stay tuned for more on that.

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Images: top (screenshot) via Columbia Power Technologies, bottom via DARPA.



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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

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