Alstom's trial full-scale tidal device has now reached full nominal power of 1MW, following a series of gradual increases in power since its immersion in January 2013.
The turbine, which is running at the European Marine Energy Centre (EMEC) in Orkney, Scotland, is connected to the grid and has now generated more than 10MWh of electricity in real operating conditions.
Alstom Ocean vice president Rob Stevenson explains that its tidal turbine has now been tested in various operational conditions, through the ReDAPT testing program. The next step will be to demonstrate its ability to operate independently, continue with planned maintenance and gather evidence for certification.
Endurance and reliability will also be tested until 2014, he says, with tests in pilot farms following, prior to the start of full commercial production.
Alstom's tidal stream energy turbine has a 22-metre long nacelle and weighs 150 tonnes. Its rotor has three pitchable blades and a diameter of 18m. It is capable of floating, meaning that the turbine nacelle can be towed to and from its point of operation and attached to pre-installed foundations.
Stevenson makes the point that this avoids the need for specialist vessels and divers, so minimising installation and maintenance costs, and reducing the timeframe to install or retrieve the turbine.
The unit operates fully submerged with no surface piercing part, in a water depth of about 40 meters. The nacelle can rotate around its vertical axis to face the incoming tide and thus extract the maximum energy.
"We are enthusiastic following the initial tests of our tidal stream turbine which successfully demonstrated the advantages of Alstom tidal turbine technology, in the challenging environment of the Fall of Warness in Orkney," comments Stevenson.
