WaveRoller PTO Passed One Year’s Rough Weather Milestone


The Power Take-Off unit of the passed an important milestone as it has now endured a years’ worth of stormy weather.

WaveRoller is a device that converts ocean waves to energy and electricity. The machine operates in near-shore areas (approximately 0.3-2 km from the shore) at depths of between 8 and 20 meters. Depending on tidal conditions it is mostly or fully submerged and anchored to the seabed. A single WaveRoller unit (one panel) is rated at between 500kW and 1000kW, with a capacity factor of 25-50% depending on wave conditions at the project site.

The WaveRoller  has gone through extensive and comprehensive testing before deemed ready for commercial roll-out. One of the areas of testing is how well the device can stand up to the forces of nature, especially the massive power of a stormy sea. In the PTO test facility, force and stroke are introduced into the PTO unit with a wave machine built specifically for this purpose. The force and stroke can be adjusted to follow the measured sea conditions in any given sea state and from any location – at full scale. When waves go above the height of 2.5 meters the sea conditions are considered rough.

” We’ve tested the PTO unit’s durability up to wave heights of 7-8 meters. We’ve learned an awful lot from this testing phase, the test facility proved very useful”, says CTO of AW-Energy Christopher Ridgewell.

Since the device is submerged for most of the time, excluding maintenance, the tests must cover an extended period of time. That’s why accelerated lifetime testing is utilized. It’s the process of testing a product by subjecting it to conditions in excess of its normal service parameters. The objective of the testing is to uncover hidden issues that are difficult to find during the design process. The typical types of failure could be fatigue damage of mechanical and hydraulic components, failure of control systems and sensors, errors in the control algorithms that reduces the delivered power.

” It’s been hard work to achieve all the test hours, but tremendously exciting. We’re very happy with the results”, said  Automation Designer Juha Manninen.

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This post was prepared by Solar Thermal Magazine staff.

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