This section explains what hydropower is and how it can be used to generate electricity for communities.

Why use hydropower?

  • It is one of the most reliable, predictable and least environmentally intrusive of all renewable technologies.
  • It is a proven technology that has been practiced worldwide for hundreds of years.
  • It is one of the most cost effective means of producing clean renewable electricity.
  • It has a substantially longer plant lifespan than other renewable technologies.
  • Hydropower plants require very little maintenance and no fuel costs.

Benefits and potential impacts of hydropower

Cost and funding

The cost of hydropower generation will vary accordingly to site location, technology used and scale of the installation. For this reason, it is extremely difficult to provide definitive costs for the installation of hydroelectricity plants.

As an indication, costs have been between £4,000 and £8,000 per kW of capacity installed. To place this in context, an 8kW hydropower plant operating at 50 per cent capacity would typically have a pay back period of seven years.

The need for substantial upfront investment often causes difficulties in financing hydropower plant installation. And claiming Feed-in Tariffs will restrict other funding options. However there is a range of viable funding sources designed to help finance the development of hydroelectricity installations.

For more detailed information on the cost of hydroelectricity and an explanation of the funding mechanisms available see below:

How much does hydropower cost and where can I get funding?

Project timescales

Project timescales will vary according to:

  • the condition of each site
  • the size of the hydro scheme
  • whether it involves a complete new build or a simpler upgrade and or refurbishment of an existing dam or weir.

Constructing a large scale dam from scratch can take several years.

How and where hydropower works

Hydropower harnesses the energy from flowing water to generate electricity using a turbine.

When identifying opportunities for hydropower there are two main considerations:

  • the volume of flowing water available
  • the height through which the water descends.
Hyrdropower - how it works

These will determine both the most suitable type of technology and the potential for electrical output.

Hydropower plants can be used in a range of different locations and scales. A small scale hydropower plant would run in a river whereas a large scale plant would use a dam with a reservoir, like Hoover Dam in the USA for example. The UK is mainly suited to small-scale hydropower schemes.

The image on the left shows how a hydropower plant works. The intake diverts water from the river into a pipe. The powerhouse holds the turbine and the outflow returns the water to the river. Layout will depend on the site context and flow rates.

For more information about hydropower technologies and some of the more detailed considerations for managing installation and maintenance, please see below:

Examples of how hydropower is used

Practical issues

In the UK, there is potential for 1,368 viable small-scale hydropower sites with an installed capacity of between 119,550 - 185,400kW.

For further information about issues to consider for different scales and applications of hydropower, please see below:

Hydropower project checklist

Case studies

Here are some examples of how some councils are already using hydropower:

Bainbridge uses hydropower in economical scheme

Hydropower plant wins awards in Settle

Torrs leads the way in providing a community hydro scheme

Links to further information

British Hydropower Association

Dorset Hydro Factsheet (PDF, 4 pages, 382KB)

Environment Agency

‘Energy recovery in existing infrastructures with small hydropower plants' by Shapes for the EU 6th Framework Program (PDF, 53 pages, 5.2 MB large file) - on the European Small Hydropower Association (ESHA) website

10 March 2011

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