See A Wave Energy Device Battered By The Sea

Wave energy can sometimes appear to be frustratingly slow in making its way from concept to reality, but a new video from the developer Aquamarine Power is a good reminder of one reason why: These devices not only need to be built to produce power at an attractive price, they need to be able to withstand some pretty wild ocean conditions.

Aquamarine Power is the UK company that makes a wave energy device called the Oyster, which is designed to be attached to the seabed at depths of between about 30 and 50 feet about a quarter-mile offshore. Its hinged flap, which is almost entirely underwater, pitches back and forth in the waves, driving hydraulic pistons that push high-pressure water onshore via a subsea pipeline to drive a conventional hydro-electric turbine. The second-generation Oyster, the 800, began testing at the European Marine Energy Centre in Orkney, Scotland, in February, and this April it was put through the wringer by a furious storm.

According to Aquamarine Power, this April 23 storm dished out waves more than eight meters (26 feet) high. The device itself is 26 meters wide and 12 meters tall. Such severe conditions are rare, occurring just 1 percent of the time, the company noted, but in a statement Aguamarine Power CEO Martin McAdam said that the Oyster’s design makes it well-suited to withstand the punishment.

“It ducks under the biggest waves which means it can operate in all weather – including severe storms,” McAdam said. “Oyster is located in the nearshore area at depth of around 12 metres. At this depth, we avoid the very highest waves which break before they reach the machine. We design Oyster to withstand the largest waves it will encounter at this depth.”

Earlier this month Aquamarine Power released some performance data for the Oyster 800, which included producing continuous power for 24 hours at one point and putting out 1 megawatt-hour of energy in a five-hour period on a single power cylinder, which the company said it believed to be “the highest sustained power output of any wave energy machine in the world.” In all, the device generation 10 megawatt-hours in 144 hours of operation, which works out to an average output of about 70 kilowatts.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.


  • Reply July 24, 2013


    The megawatt output sounds good, but the 70kW average isn’t great and would not make this really cost effective.

    • Reply July 24, 2013

      Pete Danko

      Absolutely — and I should have mentioned that Aquamarine recognized, based on the testing done the past spring, that further work needed to be done on the 800. Their statement:

      “As a result of these equipment failures the volume of our power production and availability figures have been lower than they could be, but we believe it is important to take a measured, long-term view.

      “We are now implementing our Product Improvement Programme. This is a planned shutdown which will allow us to install significant upgrades in five key areas:

      1. Installation of enhanced cylinder and accumulator modules with upgraded hoses, non-return valves and instrumentation.

      2. Installation of an enhanced control and instrumentation architecture with upgraded cable connectors.

      3. Implementation of reliability-enhancing measures following general feedback and learning to date from technical subsea issues.

      4. Analysis of all data generated on the machine to improve operating procedures and overall machine efficiency

      5. Increasing the performance of the on-shore header tank, filtration plant and accumulator plant.

      “We believe this is the best and most cost-effective way of using what we have learned so far to improve the Oyster 800’s performance and reliability. Our goal is to have the Oyster 800 operating with increased reliability through the coming winter.”

  • Reply July 25, 2013


    The “GyroWaveGen”, surface riding device, is starting to look better and better, since I think it can put out a lot more this in a much smaller and lighter package! Should be much easier to service too.

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