Plans are well advanced to install a prototype tidal generator off the French coast in the Raz Blanchard, the channel between the Cherbourg Peninsular and the Island of Alderney.

This area of fast flowing tidal current has been designated as a site for testing prototype tidal generators by the French Government with connections that allow the equipment to be linked into the grid network of EDF-EN who are behind the establishment of the tidal demonstration park.

Two French companies, Constructions Mecaniques de Normandie (CMN) and Hydroquest are behind this project which has been named ‘Searieus’. The design of the system has been developed by Hydroquest and the prototype unit has been constructed at the Cherbourg shipyard of CMN. This 1.3 MW capacity prototype has been assembled in Cherbourg on the CMN site and will be deployed in later this year at the demonstration site which is located offshore at Paimpol-Brahat. This first marine tidal demonstrator will be a key milestone in support of the development projects planned by the consortium.

"We believe in the potential of the proposed marine turbines Searieus. This turbine is simple to build and assemble and it is robust and modular to suit different depths of seabed." said Guillaume Greau, CMN's Marine Energy Development Director.

The Hydroquest turbine has been developed as a modular unit using a series of vertical axis turbines. These are combined into a series of units that can be coupled to a single generator. For the tidal demonstrator unit the turbines are mounted on a triangular base that is secured to the seabed. The turbine array has vanes at the sides in order to concentrate the water flow through the turbines. For this prototype a total of 6 turbines will be incorporated into the single unit to produce an output of 1.3 MW.

An alternative water flow turbine developed by Hydroquest can be mounted below a moored float. This has been developed for use on rivers and it is claimed that is can be used on rivers as shallow as 2 metres. A prototype of this river generator has recently been installed on the River Loire at Orleans.

By Dag Pike