Alstom (formerly TGL)
Bristol-based Tidal Generation Ltd (TGL) was established in 2005, and acquired by Alstom in 2013.
500 kW turbine
TGL developed a 500 kW tidal stream turbine – Deepgen – which was deployed and connected to the grid at EMEC’s tidal test site at the Fall of Warness in Eday in September 2010.
In March 2012, TGL announced that the device had generated over 200 MWh into the national grid since being installed.
1 MW turbine
Alstom subsequently developed a second generation 1 MW tidal turbine. The nacelle consisted of a three-bladed upstream pitch controlled rotor with an epicyclic gearbox, induction generator, frequency converter and transformer. The nacelle was buoyant so that it could be easily installed and retrieved in a single tidal cycle using small vessels, reducing installation and maintenance costs. A thruster intelligently rotated the nacelle to reflect the direction of the tide, managing ebb and flood tides to maximise energy production. Turbine blade pitch was actively managed to control load on the turbine and optimise use of tidal conditions locally.
In 2013, Alstom deployed the 1 MW tidal turbine, on the same tripod support structure as the 500 kW device, in a project partnership with the Energy Technologies Institute (ETI), known as Project ReDAPT (Reliable Data Acquisition Platform for Tidal). The turbine exported grid compliant power at 6.6 kV via a three-phase wet mate connector mounted in the base of the turbine. This configuration is analogous to a wind turbine subsea. In July 2013, the 1 MW turbine generated at its full nominal power and in November 2014, Alstom reported a total cumulative export in excess of 1 GWh.
The ReDAPT ‘Fall of Warness 3D Model Validation’ report is available to download on the ETI website.
Alstom ceased testing at EMEC in 2016.
In 2016, GE acquired Alstom, with designs for a next-generation 1.4 MW ‘Oceade’ tidal turbine in planning however GE decided to suspend development of 1.4 MW device in 2017.