Hydroelectric power
Hydroelectric power uses water flowing through a turbine to drive a generator which produces electricity. The faster the water is flowing and the bigger the drop, the more electricity will be generated. You can either:
use a water wheel or a turbine for run-of-the-river schemes which use the natural flow of the water to generate hydroelectricity
store water in a reservoir to be passed through an underwater turbine at pressure.
Hydropower is site specific and you should choose a scheme that suits your site and needs. The payback period for a small system is likely to be over ten years.
Advantages of hydroelectric power
- Hydroelectric power systems are very efficient and convert 70-90 per cent of water energy to electricity.
- Generating hydroelectric power produces no waste.
- Once installed, hydroelectric power systems should run for many years.
- Hydroelectric power is a well-developed technology.
Disadvantages of hydroelectric power
- You may need an additional power supply available to compensate for seasonal variations in water flow.
- Significant development work is required to install small-scale hydroelectric energy equipment.
- You must get planning permission and may need other authorisations such as a water abstraction and/or impoundment licence.
- Hydroelectric power is highly site specific.
- Hydroelectric power systems require regular maintenance.
Apply for environmental authorisations
Even a small hydropower plant can cause water pollution, disrupt fish migration and cause ecological damage if badly designed and built.
If you want to develop a micro-hydro power plant, you will need the correct authorisation from the Northern Ireland Environment Agency (NIEA) or the Scottish Environment Protection Agency (SEPA). To apply, you must submit supporting information including:
- a detailed description of the scheme design
- the scheme location
- the generating capacity of your scheme
- the minimum and maximum volume of water you will abstract to generate power
- river flow where abstraction stops
- your scheme's impact on wildlife, river beds and river navigation
- how you will reduce the impact on fish migration, e.g. providing fish passages and screens.
Hydropower schemes in Northern Ireland
To develop a hydropower scheme you will need an abstraction or impoundment licence from the NIEA if your scheme uses more than 20 cubic metres of water per day.
If you place structures in any waterway that are likely to affect its drainage you must have consent from the Rivers Agency.
Northern Ireland: Rivers Agency
If you abstract water for your hydropower development you need to consult with the Department for Infrastructure (DfI) to make sure your scheme does not damage fisheries.
If your scheme is in the Foyle or Carlingford catchment areas you must notify the Loughs Agency.
Hydropower schemes in Scotland
To develop a hydropower scheme you need a simple or complex licence from SEPA under the Controlled Activities Regulations. The type of licence you need and the fees you pay depend on the generating capacity of your hydropower development. This is based on your scheme as a whole and not on individual components.
If your hydropower generating capacity is less than 2 megawatts (MW) you do not have to pay any fee other than the application fee. If it is less than 5MW you pay reduced fees.
SEPA: Information on hydropower regulation
You can also obtain more information from SEPA by emailing them at hydro.enquiries@sepa.org.uk.
Apply for planning permission
In Northern Ireland, if you want to build a hydropower plant you must apply for planning permission from your local divisional planning office at the same time you apply to the NIEA.
In Scotland, if your hydropower generating capacity is:
- less than 1MW you will need planning permission from your local authority
- 1MW or more you will need planning permission from the Scottish Government.
You must apply for planning permission at the same time you apply to SEPA.
Generating renewable energy in conservation areas
In Northern Ireland, if you want to develop a site for hydropower that is in a conservation area or protected area, you must inform the NIEA.
Protected areas can include:
- areas of special scientific interest
- national parks
- areas of outstanding natural beauty
- special areas of conservation
- special protection areas.
NIEA: Interactive maps of protected sites
If your site has archaeological or architectural interest you must inform the NIEA.
In Scotland, if you want to develop a site for hydropower that is in a conservation area or protected area, you must inform NatureScot.
Protected areas can include:
- sites of special scientific interest
- national parks
- national scenic areas
- special areas of conservation
- special protection areas.
NatureScot: Sitelink interactive map of protected sites
If your site has archaeological or architectural interest you must inform Historic Scotland.
Historic Scotland: Looking after our heritage
Carry out an Environmental Impact Assessment (EIA)
If your hydropower generating capacity is above 500 kilowatts or if your development is in a protected area, you will need to carry out a formal EIA for your scheme. You must submit this to:
- the NIEA and your local planning authority in Northern Ireland
- SEPA and your local planning authority in Scotland.
NIEA: Environmental Impact Assessments (EIA)
Scottish Government: EIA Planning circular
Further information
- The Carbon Trust: Renewable energy generation
- The Microgeneration Certification Scheme: Accredited installers