High tide for world’s largest turbine

The world’s largest operational tidal turbine, rated at 1MW, has received £1.9m from the UK government’s Carbon Trust to further improve its design.

The Carbon Trust recently announced £22m total funds for six marine-energy technologies currently under development, including Atlantis Resources’ 18m-diameter bidirectional tidal-stream turbine.

The AK-1000 — which will be the world’s largest turbine when it is commercially rolled out — is expected to be capable of producing 1MW in waters that flow at 2.6m/sec.

Mike Smith, chief operating officer at Atlantis, said the Carbon Trust fund will help develop an improved version of the AK-1000 into a full-scale prototype. The improved version, he said, will be fitted with a low-RPM permanent magnet generator that does not require a gearbox.

Smith said the first version of the AK-1000, which has a high RPM permanent magnet generator and gearbox, will be evaluated this summer at the European Marine Energy Centre in the waters off Scotland’s Orkney Islands. The second version of the AK-1000 will be evaluated there for a year starting in 2011.

Unlike other tidal-turbine designs, Smith said the AK-1000’s blades are fixed pitch and therefore do not require pitch control. Also, he said, the turbine does not turn.

Smith explained: ’That’s why it has two sets of blades. The incoming tide drives the first set of blades and the outgoing tide drives the back set of blades.’

He added that when the second version of the turbine is unveiled in 2011, it will effectively only have one moving part — namely the shaft that runs through the centre of the structure.

Smith said Atlantis hopes to deploy its first commercial turbine array in 2013.