Vertical axis tidal turbine

1 min read

A tidal stream energy turbine that would be attached to a mooring rather than a rigid foundation could cut the cost and complexity of tidal energy installations.

The concept, from UK start-up company Cormarent, is being promoted this week in the US by the SETsquared Partnership, an organisation that aims to foster early-stage technology businesses spun out from universities in Southern England.

Cormarent’s vertical axis device concept, which has been analytically modelled and tested in the laboratory, is designed to take water flows from any direction without loosing efficiency.

David McSherry, creator of Cormarent, said the turbine incorporates concentric rotors that are designed to counter rotate, a feature that provides better buoyancy. He added that the device is held in position by tension leg mooring and does not need to be rigidly mounted to the seabed. McSherry said that this allows the device to be installed midstream and in water that is more energetic.

’We’re looking at our device going up to as high as 2MW in the more energetic flows,’ he added.

Cormarent’s 1MW units are being designed for waters deeper than 40m, but McSherry said that the devices could theoretically be designed for waters up to 150m in depth. The device’s main selling point, he added, will be the ease of its installation and operation.

McSherry said he expects the cost of electricity per megawatt hour generated from the turbine to be comparable to coal-fired power plants with carbon-capture and storage technology or new nuclear plants.

A scale model of the turbine with a range of 100-200kw will be built for marine trials within two years, he said.