RENEWABLE ENERGY TECHNOLOGIES

 

 

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Energy from Water                                         

Water power has been used for centuries.  Traditional water wheels use the force of flowing or falling water to turn a wheel around - either by dipping the wheel directly into the river or stream current or by diverting water over the top of the wheel where it is caught in buckets or troughs and a combination of weight and flow drag the wheel around.  Like traditional windmills, water wheels are good as driving machinery but not suitable for generating electricity.

A water turbine, on the other hand, is designed to do just that.  Water is held in a reservoir and then piped down over a wheel connected to a generator.  The pressure of the falling water will spin the wheel fast enough to produce electricity.  Water turbines come in all shapes and sizes, from the huge machines used in major hydro-electric projects to small systems capable of generating a few watts from a tiny trickle of water.

Enormous hydro-electric dams have been built in many parts of the world, but their construction and use is now being increasingly questioned.  Not only are they vastly expensive but huge new reservoirs can also change the local climate, introduce water-borne diseases, displace local populations and have far reaching political and social consequences.  Downstream, agricultural and fisheries can both suffer as the river's natural flow is disrupted.  Silting has also proved a major problem in many large reservoirs, particularly where deforestation is also occurring.  Where hydro-power is concerned, small really does seems to be beautiful!

 

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