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.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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