Product development

Since 2005, TGL has been developing a tidal stream turbine in order to generate electricity from the flow of the tides. The TGL concept has been developed with several key objectives in mind: minimising complex and hazardous operations at sea, minimising the use of costly large offshore marine vessels and exploiting tidal stream resource reliably, invisibly and economically.

TGL have designed, assembled, tested and deployed a 500kWe concept demonstrator machine at the EMEC tidal energy site, Orkney. This is sufficient to power about 300 homes when the tide is flowing. In the first 10 weeks of operation, it generated over 50MWh of power and operated at a rated power of 500KWe. Over the course of the machine commissioning, a significant amount has been learned about the operation and characteristics of the machine, the nature of the tidal flow, waves and weather impact at EMEC, as well as corrosion and bio-fouling issues on the turbine.

The turbine consists of a 3-bladed, upstream pitch controlled rotor with a relatively standard drivetrain and power electronics inside the nacelle. The nacelle is mounted onto a separate seabed mounted foundation. The nacelle rotates on the foundation every time the tide changes to face the new oncoming tide.

The foundation for the prototype is a relatively lightweight steel tripod support structure attached to the sea bed secured to the sea bed by drilling and piling.

The turbine nacelle itself is buoyant, allowing the turbine to be towed to and from the foundation site. Using an ROV, the machine is connected to the foundation via a winch rope and the machine is winched down under water and connected to the foundation using a patented clamping mechanism. High voltage electrical and control connections are then made automatically and the machine is ready to generate electricity.

TGL is now designing a 1MWe turbine, in partnership with the Energy Technologies Institute (ETI), known as ReDAPT (Reliable Data Acquisition Platform for Tidal). This project aims to collect and publish significant information into the public domain in order to benefit the entire tidal industry Information obtained will include data about the environmental impact of tidal machines, bio-fouling and corrosion, CFD modelling of turbine arrays and instrumentation application on tidal turbines. The 1MWe machine will be the production demonstrator turbine for TGL, using design processes and assembly techniques that will be used for volume production units in the future.

TGL will replace the 500kWe device installed at EMEC with their pre-production 1MWe device.  This will be mounted on the same tripod support structure and will undergo a 24-month test schedule.  TGL then plan to install a 10MWe demonstration array in 2013/14 in UK waters as a precursor to full commercial production.