The deal comes hand-in-hand with Vattenfall’s confirmation that it will buy a first next-generation device later this year from the Edinburgh-based Pelamis, so long as it is "confident” that it could move ahead with its landmark Aegir wave farm project off the Shetland Islands – a caveat that hinges on an electricity export cable being laid between the islands and the Scottish mainland.

“If Vattenfall is to use ocean energy to support its long term shift to low carbon generation it needs to be confident that the technology it uses will be safe, reliable and productive.