Most floating wind turbine concepts are derived from the marine and offshore oil and gas technology and are often semi-submersible platforms based on steel tanks connected by structural members. Barge type floating turbines are also designed around ballasts tanks.
Those tanks are ballasted to provide the right combination of buoyancy and mass to counterbalance the thrust of the wind on the turbine blades and the effect of waves and swell.
Wind farms compact layout and interconnection (anchoring, power lines) between the floating wind turbines makes very difficult the removal of a floating unit from the array, for repair or modification, during the life of field. Hence, energy producers and wind farm operators require a minimum of 20- year guarantee on the integrity of the floating platform, in particular,