Wind power giant GE faces a potential $24m of extra cost on supplying America's first commercial offshore wind farm, Vineyard Wind, after an “unprecedented” legal defeat to rival Siemens Gamesa over a patent breach relating to the giant Haliade-X turbines that are in line to equip the project.

A Massachusetts jury awarded Siemens Gamesa a royalty judgement of $30,000 per MW against GE in the patent infringement case heard in a federal district court.

Siemens Gamesa’s suit claimed that the 13MW Haliade-X infringed on two patents — one for a method of enhancing direct-drive performance, and one for a structural support that enables turbines to be scaled up in size.