Run of river systems

Many rivers have a flow rate in excess of 0.75 m per second which makes them eligible to power so-called run of river generators. The conventional method is to create a dedicated channel which

Figure 3.1

WPI turbine (courtesy of CADDET, issue 1/04)

Kaplan Turbine With Vertical Generator

accommodates a cross-flow generator which is a modern version of a water wheel or a 'Kaplan' turbine which has variable blades.

A Norwegian company, Water Power Industries (WPI), has developed a water turbine on floats that has a vertical axis rotor fitted with blades shaped like an aircraft wing. The 'waterfoils' are vertical and the flow of a river creates negative pressure which causes the wheel to rotate (Figure 3.1). The wings are continuously adjusted by computer monitoring to keep them at their most efficient angle. It is claimed that the water turbine converts 50 per cent of the energy in the water to electricity with a theoretical maximum of 59 per cent.

Assuming a steady flow of water with a velocity of 3 m/s and a regularity of 96 per cent a 15 m diameter 500 kW turbine would produce 4 million kWh/year. Not only could this system capture the energy of many rivers, it could also be situated in channels with a high tidal flow which are too shallow for other types of tidal turbine.

Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

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