By autumn, the Seattle-based technology developer’s semi­submersible unit is expected to be moored 5km off Aguçadoura, north Portugal, with a ­Vestas V80-2.0MW turbine starting a grid-connected­ testing ­programme for WindPlus, a joint-venture company led by Portuguese ­energy group EDP.

“Stability” is the mantra for the WindFloat. Its open-centred triangular hull’s three columns have dynamic ballasting and, at each base, water entrapment plates, which together use a ­principle called “added mass” to cope with the loads borne from heavy prevailing winds and the turbulence of ocean waves.