The theory seems to be, if you’re going to build a platform for an offshore wind turbine, why not integrate a wave energy device into it? Or maybe it’s, if you’re going to build a wave energy device, why not put a wind turbine on it?
Either way, this is the Energy Island concept floated (note: the rig is actually fixed on the seabed in fairly shallow water) by the Australian company Marine Power Technologies about a year ago, when the company announced that ocean engineering company Wood Group Kenny would oversee development. Now the concept is getting a nudge toward becoming a reality with a reported agreement between the Sustainable Energy Authority of Ireland and the company that could see a 5-megawatt prototype built a little more than a mile off the coast of County Mayo.
According to the The Australian, a memorandum of understanding with the SEAI, which is charged with helping “transform Ireland into a society based on sustainable energy structures, technologies and practices, would pay MPT $0.19 per kilowatt-hour for its output, with other European subsidies possibly nearly doubling that figure.
The higher figure certainly seems a more realistic price for such an innovative scheme, which conceptually consists of six 1 MW oscillating water column wave generators and a single 3 MW wind turbine (the prototype, at 5 MW, will clearly be downscaled).
An oscillating water column is a partially submerged, hollow structure, into which water enters and exits, compressing an enclosed column of air that drives the rotation of a turbine both as it is pushed out of the unit and then sucked back in.
When we first wrote about this concept, MPT said it was searching for spots along Australia’s southern coastline for deployment. But company chairman Ron Barnacle (really) told the Australian, “The truth is Ireland is much further advanced with its government departments, incentives and legal framework.”
According to the MPT website, the demonstration project would be installed at the proposed Atlantic Marine Energy Test Site that the Irish are planning to locate off Annagh Head, west of Belmullet in County Mayo.