Under the agreement, facilities will be provided at Pembroke Port for the storage, assembly, deployment and maintenance of the DeltaStream tidal generation unit, and for an operations centre during the demonstration programme, said the company.

Harbour trials of the DeltaStream device will take place in Pembroke Dock later this year, before the unit is deployed in Ramsey Sound in 2014. There, it will generate clean electricity for the homes of St Davids over its 12-month demonstration period, said Tidal Energy.

"This arrangement builds upon our commitment to support this innovative industry and is the first step in our ambition to develop Pembroke Port into a centre of excellence for marine renewables and engineering,” said Kevin Hobbs, Short Sea Director of Port of Milford Haven.

Invented by Pembrokeshire engineer Richard Ayre, the DeltaStream device - which sits on the seabed under its own gravity – consists of three independent 400kW turbines mounted on a triangular frame.

For the first deployment in Ramsey Sound early next year, one 400kW turbine will be installed in order to minimise operational and maintenance risk, with a view to scaling up to the full scale device later in 2014/2015, said the company.

"The Haven Waterway Enterprise Zone offers the opportunity to build on existing and potential new energy sites and provides an additional stimulus for energy and port related developments that will have a positive knock-on impact throughout the supply chain,” said Edwina Hart, Welsh Minister for Economy, Science and Transport.