Tidal flow energy generators have been around for some time but until recently they were not considered eco-friendly as they usually involve huge dams across tidal estuaries where wildlife feed.

However unlike wind farms, tidal energy is very dependable and in many coastal locations, extremely powerful, giving British researchers good reason to develop eco-friendly types of generators.

Now, a new type of such tidal powered electricity generator has been successfully tested at one-tenth-scale size. The idea is now set for a full-scale prototype to be tested in Orkney next year.

The TidEl system uses floating turbines that are anchored to the seabed by chains. This avoids the solid seabed-anchored masts that other tidal flow generators use.

Masts have to be designed to take enormous loads in rough weather, and costs spiral when they are sited in deeper water. Using chains instead of a solid mast helps to cut this cost.

The chain mooring arrangement allows the system to generate electricity in both directions, simply by flipping over as the tide changes direction; making it extremely efficient and easy to install and support.

The company that invented the system, SMD Hydrovision fromNewcastle upon Tyne, successfully tested its one-tenth-scale generator at the New and Renewable Energy Centre in Northumberland this January after modifying the centre’s wave tank to allow currents to be circulated in either direction.

TidEl received start-up funding from the Department of Trade and Industry, and it is now waiting on the department's decision to fund the full-scale version in Orkney.