The 23-tonne machine — a downwind design based on a ballasted, tension-moored tower that allows it to float “like an upright bottle” and yaw with the prevailing wind — had logged about 200 hours of grid-connected operation in ­Hjeltefjorden before being scuppered by the storm “Berit”.

“Berit was an extreme storm. It was not [just] the prototype that was affected, the whole of the west coast took a hammering — high winds and waves over five metres in height,” says Sway chief executive Michal Forland.

“If