The old flax mill in Gleshygolgan.
Mankind has been harnessing the power of water from at least the time of the Ancient Egyptians, who used modified waterwheels to raise water for irrigation purposes. The use of waterwheels developed over the centuries and by the time of the Industrial Revolution the use of water power was widespread. By the late 1800’s there were approximately 1200 water mills in Northern Ireland alone. Indeed many of these sites survive to the present day, albeit in various states of decay.
Hydro turbines began to appear around 1900 and were the source of electricity for many rural communities until the expansion of the National Grid in the 1960’s. Hydro Turbines have now had in excess of 100 years of development and evolution and are a well established, robust and dependable industry with examples of turbines installed around 1900 still operating over a century later.
Many schemes can be described as run of river, using a weir to divert water from the stream to an intake, from where it is conveyed via an open channel or sealed pipe to a hydro turbine. After passing through the turbine, the water is returned to the stream.
The energy that can be obtained from the stream is a combination of the available water flow in litres per second and the vertical distance (head) that it falls. A little volume of water and a high head, or a large volume of water and a low head, will both generate energy, while a large volume of water combined with a high head is most beneficial.