A new wave power farm is due to be launched shortly off the coast of Italy near Pisa. The farm will use the R115 150kW wave device currently being developed by London-based company 40South Energy. Unlike previously developed wave devices that sit on the surface of the sea and therefore have to be fairly bulky in order to withstand powerful storms, the 40South device is deployed beneath the surface where it can still generate power without risk of being damaged by heavy swells. This is a particularly important feature given that the seas off the coast of Pisa are literally pounded by powerful waves from the Mediterranean Sea.
In the past the sheer power of the ocean has meant disaster for wave and tidal projects using surface-based technology. One such example was the wave project deployed off the coast of Portugal using technology developed by the Edinburgh company Pelamis. Two months later the project had to cease operations due to a variety of technical and financial problems.
The R115 consists of two connected sections deployed at depths greater than 40 metres and linked by several arms which generate power from electric dynamos. The two sections sit in the water at different depths, one above the other. The whole structure can adjust its position automatically according to the conditions and is installed with the aid of cable connectors and mooring which are prepared in advance. The device is assembled in a nearby harbor and towed out to sea by a standard towboat where it is then connected to the cable and mooring. The machines are then instructed by remote devices to find the most appropriate position in the water.
High density polyurethane foam similar to that used to make surfboards is used by the device to achieve the correct weight for the two sections. These foam boards are applied to a steel lattice on each section of the device and are in turn covered by sheets of wood.
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