A wave energy device that can be fitted to an offshore wind turbine has successfully completed feasibility testing, it was announced yesterday, moving the technology closer to commercialisation
Its developer has said that the system will be best suited for turbines installed as part of Round Three of the government’s offshore wind development.
The 500kW Wave Treader, developed by Aberdeen-based Green Ocean Energy, is designed to be attached to an offshore wind turbine, adding to its energy output while sharing the infrastructure costs of cabling and foundations.
The device was tested as part of a feasibility study into its commercial application, a study that was funded by a £60,000 grant from npower’s Juice scheme.
Under the scheme, npower customers can opt into a Juice “tariff” for a year, after which npower will donate £10 per customer towards marine renewable energy projects. So far it has contributed £2 million to the marine renewables industry.
Wave Treader was also granted proof of concept.
Managing director of Green Ocean Energy, George Smith, who invented Wave Treader, said this week: “We have drawn on our extensive skills and experience in the energy sector to develop this technology. The support we have received from npower through the juice fund has enabled us to take a huge step forward in preparing the device for widespread use in the offshore environment.
These are exciting times for the company and we look forward to eventually seeing the device incorporated into offshore wind farms,” he added.
Green Ocean Energy said yesterday that a full size prototype could be ready for testing in 2010, with commercialisation in 2011.
Helen Steed of npower’s Juice fund, said: “We are delighted with the results of the Green Ocean Energy Wave Treader. The device is the first of its kind and shows tremendous potential in utilising existing offshore infrastructure to generate clean renewable electricity. This is exactly the type of project that the npower Juice fund was created for.”
Designed for installation 2-3 miles out to sea, Wave Treader comprises sponsons mounted on the end of arms both in front and behind the wind turbine’s column. Hydraulic cylinders are attached between the arms and an interface structure. As the wave passes along the device, the sponsons and arms lift and fall, stroking the cylinders, pressurising hydraulic fluid which spins hydraulic motors and then electric generators.
Electricity is exported to the grid using the same cable as the wind turbine.
And to generate the most power from the waves, the device can turn to face the direction of the wave train, as well as adjust to allow for tidal range.
According to Green Ocean Energy, Wave Treader would be best suited for Round Three offshore wind turbines, which are located further off the coast and in rougher conditions than their Round One and Two counterparts.
Round Three is the third cycle in the government’s development of offshore wind farms, and is expected to comprise larger wind farms, further offshore than previously.
In addition, the company said yesterday that mounting the device on the foundation of an offshore wind turbine makes the technology “more commercially viable”, because of the relatively low technical risk.
Wave Treader was borne out of its sister wave generator, Ocean Treader, which has a similar design, but is free floating as opposed to fixed on to a wind turbine.
Ocean Treader, which also has a capacity of 500kW, already has proof of concept, and Green Ocean Energy has said it is currently raising finance for a full scale prototype, to begin offshore testing in 2011.
It is intended for use in arrays in the north Atlantic Ocean, and the firm estimates that the farms can generate 43MW per square kilometre of ocean.
Green Ocean Energy was formed in 2005 to take forward the concept of Ocean Treader, which had received funding and a patent application the year before.
The firm said today that the machines have a design life of 25 years.