Hydro power is produced from the movement of a mass of water: in rivers, streams, rising and falling tides through lunar cycles, wave and energy from sea currents. The rivers and canal systems in Cheshire could provide opportunities to develop small scale hydro power. Small scale is defined as a hydro energy plant producing less than 5 MW of electricity. This type of scheme has minimum environmental impact unlike large tidal or dam schemes, and yet with developments in technologies it has become a more attractive and cost effective proposal.
There are currently 5 small scale hydro sites operating in the North West region with a generating capacity of 1.6MW. Most of these schemes are small scale with an output between 50 and 200kW. The target for the region by 2010 is for a total of 19 schemes with a total capacity of 5.6MW*From Power to Prosperity, Sustainability North West, March 2001.
The water resources within Cheshire are sufficient for the County to play a considerable role in helping the region achieve its target.
Technology
The old techniques using waterwheels to transfer energy from water to mills have developed and been replaced by turbine and generator technology. Useful power can now be produced from a small stream providing a few hundred watts for domestic uses, to a minimum of 25kW for commercial uses. The available power is dependent on the amount of water, the flow rate, the height which the water falls, and the force of gravity. How a scheme converts this into electrical power will determine its efficiency, maximum efficiencies can be up to 80%, for smaller schemes a more realistic aim is 50%.
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