New Tidal Power Unit Due for River Testing in 2008
22 September 2007
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| Schematic of the Proteus tidal power device. Click to enlarge. |
Hull University’s (UK) Marine Renewable Research group has been working with a local consortium, Neptune Renewable Energy Ltd, on a device that converts tidal power into energy.
The Neptune Proteus Tidal Power Pontoon consists of a 4m x 4m vertical axis Savonius (Binks, Michell or Crossflow) turbine mounted in a patent pending symmetrical accelerator duct beneath a standardized 8m x 13.02m steel barge for estuarine sites.
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| Mean spring tidal power density in the UK. Click to enlarge. |
The vertical axle connects simply to the gearbox and generator/alternator on the top of the pontoon with associated valves and supply controls. The power pontoon is easily moored in the free stream, thus minimizing environmental impact and operates equally efficiently for both flood and ebb currents. Theoretical work and 1/100th scale laboratory modelling suggests an efficiency of 60-80%.
Manufacturing costs of the device are minimal, which means that for the first time ever, tidal electricity can be generated at commercially competitive prices. Once manufactured, ten Proteus devices could potentially provide 15% of Hull City Council’s energy requirements.
The Proteus devices have been tested in the University’s research facility at The Deep, Hull’s futuristic submarium. The device generates power by using computer-controlled shutters that direct tidal currents onto a large multi-paddled water turbine. The workings of the device have been developed through honing mathematical applications and using the results to conduct practical experiments.
The next step is to create a full-size prototype that would be positioned in the Humber.
The Proteus device has now been patented by the Neptune Group, who are raising funds for the first full-scale demonstrator version. This will be project-managed by the University’s Environmental Technology Centre for Industrial Collaboration (ETCIC), and is due to be tested in the Humber in 2008.
I could see this working in the Severn estuary and perhaps, due south of the Isle of Wight. Elsewhere, tidal power density in the UK isn't nearly as high.
Even so, the hinges sound ambitious, brackish and salt water are quite corrosive over time. A design with just one moving part (the rotor) might be better, even if efficiency is reduced. It's hard enough to get bearings and seals to last for several decades in flowing water laden with fine sediment. If a simplified Mk I does work well, they can always add the hinged/deformable accelerator scoops for Mk II.
Posted by: Rafael Seidl | 22 September 2007 at 07:50 AM
Obvious optential for power generation in rivers without blocking flow, if it can be shown that it does not harm migrating fish, or be modified to not harm them.
What about using non-corrosive materials, or coatings, like plastics on the hinges?
Posted by: mds | 22 September 2007 at 09:12 AM
Resident fish would also be a concern.
This is better than a dam, but disruption of tidal flows will effect oxygen, nutrient, sediment, and temperture mixing. I suspect this is less of an issue in rivers. The company drawing does make it look like the device is designed to fit closely between surface and bottom. Might want to leave room underneath for low water if used in river. Device would have to stand up off bottom.
What about protection of the device from semi-submerged debris, like submerged logs?
Posted by: mds | 22 September 2007 at 09:34 AM
@ mds -
flow speeds in rivers are high near the surface, low near the bottom. Usually, a dam of some height is used to produce hydroelectric power from rivers. Conventional axial turbines, venturi pipes and systems to prevent fouling are employed. Even shallow dams far from the river's source in the mountains are useful, see e.g. this cross-section of the Freudenau plant in the Danube in Vienna, Austria:
http://de.wikipedia.org/wiki/Bild:Kraftwerk_Freudenau_Querschnitt_Maschinenhaus.jpg
Conventional sluices (not shown) allow shipping to pass in both directions.
Posted by: Rafael Seidl | 22 September 2007 at 11:07 AM
They put some in the Hudson recently and produce enough power to run all the electric needs for a small grocery market on shore. The first version broke, but they got the second one to work dependably.
Posted by: sjc | 25 September 2007 at 01:17 PM