Alstom will supply 66 of its 6MW Haliade machines to the North Sea wind farm, previously known as MEG1.
The deal is a boost for Alstom, representing a major breakthrough for the Haliade outside its domestic French market.
Merkur was initially slated to use turbines from Areva, now Adwen, before the insolvency of its original developer Windreich.
Rechargerevealed last month that the Merkur project company was mulling a change of supplier.
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