Hydro power is a very practical alternative energy source. In the 1940s there were many villages throughout the UK using them. At the present time it is not a cheap form of energy production as there is the expensive Water Extraction Licence to purchase from the Rivers Authority. This has to be bought even though the water is not removed from the water course neither is it treated with chemicals or treated in any way. Of course once it has been extracted it is then considered Process Water and tested to check its fitness to return to the river. It is almost the ultimate in RED TAPE. It could be considered a cash extraction licience.