Bristol Channel energy fence seeks funds

Tidal energy technology originally developed at Oxford University claims higher outputs than turbine designs

 
Plans to build a 30MW capacity tidal “energy fence” in the Bristol Channel by 2020 have moved forward with a the first funding round for the £143 million project

The tidal energy technology, which is similar to a water mill, was developed by Oxford University’s Department of Engineering Science for use in shallower, lower velocity tidal waters and is being bought to market by spin-out Kepler Energy.

The technology consists of a stressed truss configuration “Transverse Horizontal Axis Water Turbine (THAWT)”. According to Kepler, modelling and testing has shown outputs several times higher than those achievable by propeller-type turbines placed at the same site. The increased performance is said to arise from the greater rectangular swept area of a THAWT rotor compared to the depth limited circular swept areas of multiple propeller type rotors.

 The turbine's blades are configured so that the rotor does not require a supporting structure around it, leading to lower parasitic drag, lower power losses and simple, cheaper construction with longer rotors across the flow.
The first phase of the tidal fence scheme will be up to a 1km long, but Kepler believes that its tidal fences in the future could be 10km or longer.

Chairman Peter Dixon said: “As our tidal technology can operate in lower velocity tidal waters, there is greater scope for its deployment in the UK and overseas. It means that we can achieve greater economies of scale as our projects are deployed.

“We can happily co-exist with tidal lagoons, and the power peaks will occur at different stages of the tide, meaning that the combined output into the grid will be more manageable. In addition, our costs of production will be in the range £100 to £130 per MWh for utility scale production, cheaper than lagoons and in time cheaper than offshore wind generation."