By a Newsnet reporter
A wave energy device being tested in the waters around Orkney has generated the best levels of sustainable energy ever seen, it has been reported.
The Oyster 800 device, developed by Aquamarine Power, has been operating at the European Marine Energy Centre (EMEC) in Orkney since 2012.
Results released by the company show that, amid terrible storm conditions, the device generated 10 Megawatt hours of electricity over 144 hours of operation. In one day in April it generated an incredible 1 Megawatt hour in five hours from just one cylinder.
Aquamarine Power said it believed the results were the highest from any wave energy device anywhere in the world.
Aquamarine Power chief executive Martin McAdam said: “Since the Oyster 800 flap was raised from the seabed on February 14 this year, we have learned a tremendous amount about how Oyster operates in real sea conditions.
“This year the Oyster 800 has been operational in significant wave heights of 5.3 metres and peak waves of 9 metres. The concept works, and our onshore hydroelectric plant is operating well. The Oyster 800 structure has performed well in the most arduous storm conditions.
“We are now starting to see some very promising power production figures – including sustained generation of 1MWh in a five hour period. Normally the system operates on two power production cylinders, but since February Oyster 800 has been operating on only one functioning cylinder – a capability we included in the original design – which makes the figures even more encouraging.”
The device has now been shut down for improvements to be carried out in order to increase performance, reliability and availability in nearshore wave technology. Testing in the extreme conditions has allowed the company to identify component weaknesses, which have now been redesigned and are being tested.
The Oyster has been operating intermittently throughout the summer of 2012 resulting in minimal electricity generation. This year was the first time the Oyster had been allowed to generate any significant amounts of power.
Martin McAdam added: “We have been as open as we can about the challenges we face, particularly in this hostile offshore environment,” he said.
“Many components, including control and instrumentation cable connectors, hydraulic hoses, non-return valves and accumulators have performed much less reliably than expected.
“For example, Oyster uses four non-return valves on each of its two hydraulic cylinder modules.
“As part of the Oyster 800 test programme we installed four from one manufacturer on one cylinder and four from a different manufacturer on the other cylinder.
“Whilst the valves on one cylinder have operated perfectly since installation, the other set of non-return valves failed from the outset.
“We’ve spent time with the manufacturer of the failed valves to understand the failure and design upgraded valve components. This way we are both learning, and developing expertise within the supply chain. It is a similar story with our hydraulic hoses, accumulators and control and instrumentation systems.”
The Oyster was manufactured at the Burntisland Fabrications’ yard at Methil in Fife where it was unveiled by First Minister Alex Salmond in July 2011 before being transported to the EMEC centre in Orkney.
Oyster 800 was the first of three devices to be installed at EMEC. All three Oysters are to be linked to an onshore hydro-electric plant to form a 2.4MW array.