The big news in wave energy has been coming out of Oregon this year, with the launch of a federally backed test site and system, and the licensing of a grid-connected commercial project, now scheduled to deploy next spring.
Meanwhile, way over on the other side of the continent, Neptune Wave Power has been quietly testing its own device – and yesterday the company reported those tests have gone well.
Neptune, based in waveless Dallas, actually has Oregon connections. It received backing from the Oregon Wave Energy Trust – a state-supported organization promoting the wave power industry in Oregon – and in 2011 put an early iteration of its device through its paces at the wave lab at Oregon State University.
But when it came time to test a 3-meter version of its wave energy converter, Neptune chose the Atlantic, where tidal power has mostly been the focus, rather than the Pacific. The reason? The University of New Hampshire’s Center for Ocean Renewable Energy (CORE) offered a no-fuss, no-muss opportunity to plunk the buoy into the water without delay.
The New Hampshire site, in 170-foot deep waters about six miles off the coast near Portsmouth, was developed some 15 years ago to test aquaculture projects. In 2008, CORE was founded to take advantage of renewable energy opportunities. Fully licensed and with dedicated dock and launch facilities, research vessels and mooring gear and expertise, “It had everything we needed to move forward with our next step,” Neptune President Eddie Mayfield said in an interview with EarthTechling.
If you’ve followed our coverage of marine power – wave and tidal – you know the sector is very young in the United States – “embryonic” was the term Mayfield used (in Europe, it’s a bit more advanced; in its infancy, perhaps). That makes it incredibly difficult for companies to find funding, so things tend to move frustratingly slowly. But being new and unproven also makes the sector fun: Dozens of interesting different design are in play.
Neptune’s wave energy converter is in that category known as a point-absorber — moored to the sea floor by a cable, it floats at the surface, absorbing the energy of the waves that buffet it. But it does so in a unique and elegant way: A horizontally set pendulum inside the sealed buoy – “the can,” Mayfield informally called it – swings around as the buoy rocks and moves from side to side. Sometimes the pendulum goes around and around in one direction; sometimes it goes forward a bit, then back the other way. “It doesn’t really matter, because as long as it’s driving the shaft, it’s driving the generator,” Mayfield said.
On page 2: Keeping the device in tune with the waves… What does matter, however, is that the device stay in tune with the shifting power of the waves; the better it does that, the more efficiently it will pull energy from the ocean. The Neptune team accomplishes this by moving the pendulum inward or outward from the shaft to match the power of the waves – in essence, shifting gears up and down to keep torque as high as possible without stalling out. At the same time, power from the shaft to the generator is adjusted to find that perfect spot where production is maximized without stopping the system.
In the New Hampshire test, which Mayfield said verified the patented tuning technology, Neptune’s engineers adjusted the device remotely, via wireless communication, but down the road they aim to automate the process.
Mayfield said the device will come out of the water soon, before winter. The company’s planned next steps – as it searchers for series B venture funding – will then be to refine the 3-meter device while concurrently developing a 15-meter model that would be closer to the ultimate size envisioned.