Hydroelectricity systems use piped water to turn a turbine which generates electricity. The greater the height (or ‘head’) and the more water there is, the more electricity can be generated. The amount of electricity a system actually generates depends on how efficiently it converts the power of the moving water into electrical power. Small or ‘micro’ hydroelectric systems (15 kW or less) can produce enough electricity for lighting and electrical appliances in an average home.

• Highly efficient (50 – 70%)
• Predictable outcome as output does not vary much
• Maximum output in winter therefore good match on demand
• Can be connected to grid or stand-alone battery store
• Civil works required and can add substantial cost
• Most common type is a Pelton Wheel

Approximate installation costs:
• Up to 1 kW £625 – 3,500
• 1 – 10 kW £1,900 – 15,000
• 10 – 50 kW £50,000 – 300,000
FiTs payments available for 20 years (19.9p / kWh for schemes smaller than 15kw and 17.8p / kWh for 15 kW to 100kw schemes).

Planning permission and SEPA ‘CAR’ licence:
• Planning may be required for power house or noise issues
• SEPA should be consulted – a ‘CAR’ licence will be required (Water Framework Directive). The minimum cost is £588 plus possible costs of advertising
• SNH should be consulted

To help decide if a hydro system is right for you, there are a few key questions to ask:

• Is there a river or stream close to your home?
•   You’ll need access to a water course and the right to build along it.
• What is the maximum height or’head’?
• This is the vertical distance from the point of ‘abstraction’ to where the turbine would be located.
• What is the average flow?
• You can often work this out if you know the average rainfall and the size of the catchment area. Another option is to fit a V-notch weir and take daily streamflow readings and daily rainfall readings to help work out average flow. With ‘head’ and streamflow, you can work out what the power output might be. This site makes that calculation: www.reuk.co.uk/Calculation-of-Hydro-Power.htm

For more information on Hydro please visit here.