Small Thawt, but big thinking - Isis Project No 3325

A novel tidal turbine has been designed and tested which allows the scalable exploitation of tidal resources by a device that has low mechanical complexity.

Sea-green Energy

Tidal currents provide a highly predictable source of energy that can help to reduce our dependence on fossil fuels. The currents, created by the relative positions of the sun and moon, can be enhanced by geological features to speeds where extraction of energy is an attractive proposition. There are many such sites around the world, and the UK is estimated to have 10% of the global extractable tidal resource.  Tidal currents are sub-surface, so tidal turbines have minimum visual impact, unlike wind farms or estuary barrage schemes.

The majority of tidal turbines in development are axial flow devices that rotate perpendicular to the current direction, like a common wind turbine. The size of the device and area of current they can intersect is limited by the depth of water requiring 10s or 100s of these devices in order to achieve large-scale and significant power generation. 

A novel THAWT

A team of Engineers in Oxford have designed, built and tested lab scale versions of a turbine that is mechanically much simpler than axial flow devices. The Oxford turbine, called THAWT (Transverse Horizontal Axis Water Turbine), has been designed to intersect the largest possible area of current, and has resulted in a device that can be scaled regardless of the depth of water in which it is situated.

The result is that if THAWT devices were extended across the same area as axial flow devices.

THAWT would require:

• less generators,
• less primary seals
• less foundations

And consequently THAWT would incur:

• lower capital costs
• lower maintenance costs
• lower operational costs

To see Professor Martin Oldfield discuss the THAWT tidal turbine and the challenges involved, click here (External Link).

Patent Status

This work is the subject of patent application.  Isis would like to talk to any companies interested in partnering this timely opportunity. Please contact the Isis Project Manager to discuss this further.

Request Further Information: Project Number 3325 Small THAWT, but big thinking