The owner of one of the world’s largest offshore wind farms more than 20 kilometers off the coast of England, has lodged a large claim for delayed completion due to defective construction against the contractor, Fluor Corp.

The claim is reportedly at least as large as the one worth about $480 million that Fluor has already filed against the owner, Greater Gabbard Offshore Winds Ltd., also for delays over the 504-MW project in the outer Thames Estuary.

Originally set for completion by 2011, the wind farm is now not due to be fully operational until later this year, according to Edinburgh, Scotland-based utility SSE plc.