Global engineering company Trelleborg has unveiled the world's first full-scale offshore floating Hywind wind turbine, which uses foam buoyancy technology.
"It is subsea technology that has already been extensively proven," commented Gary Howland, Renewables Sales Manager for Trelleborg Offshore.
"Trelleborg Distributed Buoyancy Modules (DBMs) developed for deepwater support of umbilicals and risers in the oil and gas industry are ideal for this application; helping reduce project risk by using proven technology.
The subsea portion of the turbine is critical.
"People see the tower and turbine, but forget that the expertise in designing the subsea portion is also critical, as ultimately it keeps the whole turbine afloat.
"The dynamic floating structure weighs 5,300 tonnes and is 165 metres tall with a total of 65 metres above sea surface. The 13-kilometre of power off-take and communications cabling attached to the structure further adds to its weight."
Trelleborg Offshore designed and supplied 45 off polymer-coated syntactic foam DBMs, which supply buoyancy support for a three-tonne, 100-metre section of cable as it exits the turbine spar and descends to the sea bed at -220 metres.
The buoyancy modules include an internal clamp for secure fastening and precise positioning on the cable. The cable is supported mid-water in what is known as a 'Lazy Wave' configuration, featuring gentle long radius curves that minimise stress on the cable while accommodating natural movement created by wind and waves.