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Generating renewable energy

Hydroelectricity

Benefits

  • cheap heating and hot water
  • affordable option for off grid homes
  • cut your carbon footprint

Whether it’s from a small stream or a larger river, small or micro hydroelectricity systems, also called hydropower or hydro systems, can produce enough electricity for all electrical appliances and lighting in the average home.

How do hydropower systems work?

All streams and rivers flow downhill. Before the water flows down the hill, it has potential energy because of its height.

Hydropower systems convert this potential energy into kinetic energy in a turbine, which drives a generator to produce electricity. The greater the height and the more water there is flowing through the turbine, the more electricity generated.

The amount of electricity a system generates also depends on how efficiently it converts the power of the moving water into electrical power.

Benefits of hydro systems

24/7 operation

A hydro system can generate 24 hours a day, often generating all the electricity you need and more.

Cheap heating and hot water

A hydro system may generate more electricity than you need for powering your electrical appliances and lighting your home – so you could use the excess to heat your home and hot water too.

Cheaper option for off grid homes

Hydro schemes are one of the most reliable alternatives to mains supply for isolated properties. Installing a hydro system can be expensive, but in many cases, it’s less than the cost of getting a connection to the grid if you don’t already have one. Find out more about off grid options.

Cut your carbon footprint

Hydroelectricity is green, renewable energy and doesn’t release any harmful carbon dioxide or other pollutants.

Will hydropower work for me?

Hydropower is very site specific. Most homes will not have access to a suitable resource even if they have a watercourse running nearby.  If you might have a suitable site, the next step is to contact a certificated installer, who will assess your site.

To be suitable for electricity generation, a water source needs to have a combination of:

  • Flow – how much water is flowing per second.
  • Head – a difference in height over a reasonably short distance.

Find out more about hydropower systems and the planning permissions and licences required.

It’s also important to consider what happens to the river in summer. The minimum flow during dry periods is usually the deciding factor, no matter how impressive the river looks when it’s in flood.

If there is a good hydro resource in or near your community, it might be worth developing it as a community energy project, rather than as a system to supply just one home.

If you live in Scotland, find case studies and examples of homeowners who have installed a micro hydro system using our Green Homes Network tool.

Costs, savings and financial support

Costs for installing a hydro system vary, largely depending on the location and equipment required for install.

Maintenance costs also vary but are usually low. Hydro systems are very reliable.

Savings will depend on the amount of electricity the hydro system generates. This is affected by the number of hours the turbine can run in a year, which in turn depends on how often the level of the river is high enough to supply the system. Your installer will predict this for you and provide estimates on the amount of electricity you can expect to generate.

Signing up for the Smart Export Guarantee tariff means you can receive payments for exported electricity for qualifying systems. Please visit our Smart Export Guarantee page for more information.

Hydro systems were eligible for Feed-in Tariff scheme (FITs) payments. The FITs scheme closed to new applications on 31 March 2019. If you have already installed your hydro system on or before 31 March 2019 you may still be able to apply. For more information about the FITs scheme and recent changes please visit our Feed-in Tariff page.

Maintenance

Once installed, most systems can last for 40-50 years, with low running and maintenance costs and could last for longer if well maintained.

There is potential for damage by debris carried downstream at times of flood, however screening the intake should minimise this risk.

Helpful resources

  • The guide to hydropower construction best practice has information for scheme owners and those working on hydro construction sites in Scotland.

    Read the guide
  • Find out more about different kinds of technology at the British Hydro Association.

    Find out more

Last updated: 7 September 2021