The facility, located in Denmark, is called Wave Star and generates electricity even from very small waves
The Wave Star was the vision of Niels and Keld Hansen, who came up with the concept in 2000 when they were sailing near their parents’ summer house and wanted to find a way to harvest the energy beneath them. In 2003, the company ‘Wavestar Energy’ purchased the rights to the machine after seeing the huge commercial potential of wave energy. Wavestar is a multi-point absorber equipped with kinetic-energy harvesters called floats, which move up and down with the kinetic motion of the waves, and this motion is transferred via hydraulics to rotate power generators. Apart from enabling continuous energy production and a smooth output, the system also has outstanding sea survivability, as in the event of storm, the floats can be lifted to a safe position, while it can also be remotely operated. The company’s target is to combine this technology with wind and solar power, in order to form energy parks.
Growing in scale
In 2004, extensive tank testing (more than 1300 different test runs) was performed on a 1:40 scale model in order to optimize the concept and document the electrical power production in typical North Sea waves.
Early 1:40 scale Wave Star Energy test model in the wave test tank at Aalborg University in 2004.
In 2005, the first grid connected 1:10 scale model was designed and built for operation in the sea at Nissum Bredning, on the west coast of the Jutland peninsula in west Denmark, where the waves are approximately 1:10 of North Sea waves. The system contained all the instrumentation and control systems necessary to work unattended round the clock. After the final dry testing, the model of 5.5 kW was installed on April of 2006 and put into full-time operation 3 months later. Since then, it has logged more than 15,000 operational hours in the sea and been through 15 storms without any damage.
Nissum Bredning installation at Lemvig Municipality (it can also be seen in Google Earth)
The 1:2 scale model is a prototype operating with 2 floats (5m in diameter) and was installed 300m off the coast at Hanstholm in the North Sea on September 2009. Its installation lasted two days and the machine was connected to the grid in February 2010. Since May 2010, a monthly production report is conducted and delivered to Energinet.dk, who pays Wavestar when electricity production is above the pre-defined limit. Energinet.dk studies the data to show correlation between wind and wave.
Calculations and tests show that the machine produces energy around 90 percent of the time, and that it will run on maximum power 30 percent of the time. When appropriately scaled to the dominating wave climate, the power of the machine becomes around 11 times greater, each time the machine doubles in size. Wave Star aims to produce a 1 MW machine for big oceans, ready for sale in 2017, but it is not stopping there. The full size plant (C5 Wave Star) will have 20 floats of 5m in diameter and produce 500kW of energy (enough to power 400 homes), whereas C10 Wave Star will be double in size, capable of handling twice the wave height, and with floats of 10m in diameter, will produce 6 MW of energy (enough to power 4000 homes)!