Revolutionary device benefits

Green-Tide’s revolutionary, run-of-river and tidal stream electricity generating device is able to be mass produced, is cheap, easy and quick to install and maintain. Current technologies use bladed fans or oscillating hydrofoils to convert kinetic energy in a flowing current of water into rotary motion driving a generator. Green-Tide’s technology is distinctive from existing tidal stream devices in that it causes the flowing water to rotate, the device’s specially designed turbine then captures the rotational kinetic energy. This results in the following key benefits:

• Due to the faster water movement created by the vortex our device is able to operate in much slower river currents or tidal streams making more sites economically viable as electricity generation sites and, in the case of Tidal Stream, more of the tidal cycle available to generate power.
• The rotor in our device rotates significantly faster than existing designs reducing generator gearbox complexity, this would significantly reduce the capital and maintenance costs.
• By using a reaction turbine, energy is extracted by changing the direction of the flowing water rather than a blade cutting through the water flow as with competitor devices. Therefore debris or sea life pass through G-TT’s device without damage to the turbine, the debris or marine life reducing maintenance costs and damage to sea or river life.
• As our rotor moves with the spinning vortex there is reduced wear on the rotor from abrasion. This would lead to a longer service life for the turbine reducing O&M costs.
• G-TT’s turbine forms a vortex which has a very stable structure with loads evenly distributed radially, this puts much less strain on the turbine reducing failures due to fatigue and wear on bearings etc. further reducing O&M costs.
• Limits to Marine Noise have been set at 183 dB SEL with a 224 dB peak over an acoustic range between 10Hz and 10kHz and at a 1/3^rd octave band of between 63Hz and 125Hz of 100dB in the EU Marine Strategy Framework 2008. Monitoring across EU waters will be in place by 2015 and full compliance by 2020. Open bladed turbines are likely to generate a great deal of noise at the frequencies covered by this directive so are unlikely to comply to this new directive. The design of our turbine incorporates features similar to those used in state-of-the-art submarine propulsion systems designed to reduce noise to prevent detection. As a result our device produces a very little swirl in the exiting flow resulting in lower marine noise than existing open bladed turbines. QinetiQ are World leaders in submarine propulsion systems and bring particular expertise in this area to the project.
• Pre-conditioning the flow into the turbine and the swirl-free out-flow also means that our turbines can be sited closer together without risking damage from wake effects from upstream turbines. This enables greater density of devices in farms or along rivers reducing the rental overhead per MWh generated and reducing cable lengths between turbines, greatly improving the economics of a farm of turbines.