Page 12: of Marine Technology Magazine (November 2011)

12MTRNovember/December 2011The SR250 floating turbine from Scottish renewable energy company, Scotrenewables, is a floating tidal device. The 33m, 100 ton SR250 is fixed to a mooring turret which is tethered to the sea floor. The con- struction of the turret allows the tur- bine to move with the direction of water movement, positioning itself automatically for optimal energy cap-ture in much the same way that wind- mills turn to face the oncoming wind.Harnessing the renewable power is just one part of the process ? it also needs to be exported to the grid onshore through a medium voltage cable. The Scotrenewables design, that combines a dynamic turbinemounted on a tethered turret, can put significant strains on the riser sectionof the export cable. Designing the right cable and con- nector infrastructure system was important from the outset to ensure that power harnessed by the turbine could be reliably fed to the onshore grid. Scotrenewables chose MacArtney to provide the infrastruc- ture for its 250kW prototype and its design is a result of close cooperation between engineers from both compa- nies.Where Dynamic Meets Anchored Infrastructure that connects dynamic systems to static cableanchoring needs to be carefullydesigned to reliably maintain power and signal contact as the turbinemoves horizontally with the tide as well as vertically with wave move- ment. The SR250 turbine has a turret and a vertical swivel. At the turret, a 6.6kV wet mate connector acts as a stab plate. As the turbine turns aboutthis axis to face the water flow, this swivel turret holds the dynamic unit on the anchoring and the swivel ensures that the signal and power news MacArtney Brings Offshore Power Ashore Earlier this summer, 2011, Orkney based Scotrenewables launched their prototype floating tidal turbine, the SR250, designed to minimize the installation and maintenance costs of tidal energy compared to seabed-mounted tidal tur- bines. Vital infrastructure for this renewable energy project was designed and supplied by MacArtney Underwater Technology. MTR#9 (1-17):MTR Layouts 11/29/2011 10:18 AM Page 12