A small team of engineers in Cornwall has made a breakthrough with the development of a turbine that they claim could solve the commercial viability of tidal power.
The Osprey turbine can be used to create electricity offshore at sea or in tidal rivers and inland waterways. Following successful testing of a model rotor, a reduced-scale model prototype has been developed to assist in the design of a full-scale prototype.
Research and development consultants in renewable energy, FreeFlow 69, conceived the turbine concept while working on design and development work for its offshore Ocean Hydro Electricity Generator (OHEG), a concept using tidal energy to create electricity 24 hours a day.
The Osprey turbine is a vertical axis free flow device which produces power independently or as part of a larger system. Power output is expected to be from 1kW up to 5MW in a multiple system.
Parts for the prototype model were pre-fabricated in stainless steel by associate company Able Engineering of Swadlincote, Derbyshire and assembled in Fowey.
With the significant advantage that the gearbox and generator are above the water level, it operates effectively in variable depths to maximise the efficiency of the power available through the tidal cycle, or in differing river heights.
It is also environmentally friendly and will not interfere with marine or river life, can be mounted on the sea bed or suspended on pontoons, is bi-directional and will turn the same way in a flooding or ebbing tide.
Due to its modular design, a bank of Osprey turbines can be built up and added to in order to generate more power.
"We already have a patent application in place and plan to build a full size prototype by the Autumn," said Mr Cooke. "If this is successful, as we are confident it will be, we intend to manufacture a range of small units for river applications, followed by a range of cross flow turbines for conventional micro hydro plants."
A prototype for an Archimedes screw type version turbine will also be produced for rivers where a weir or leat is available, such as old mill sites.
We're pleased to introduce a comprehensive line of micro-hydro water turbines, including LVM's AquaGen and Ampair's Aquair UW submersible propeller turbines, Harris Pelton and Stream Engine impulse turbines, and a comprehensive line of small reaction turbines including the LH1000, Nautilus, Neptune, Niade and Power Pal micro-hydro power systems. 
