Use running water to generate electricity, whether it’s a small stream or a larger river.

Small or micro hydroelectricity systems, also called hydropower systems or just hydro systems, can produce enough electricity for lighting and electrical appliances in an 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. Hydro power 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 can be generated.

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

Find out more about different kinds of technology at the British Hydro Association website.

The benefits of hydro systems

  • Cut your electricity bills
    A hydro system can generate 24 hours a day, often generating all the electricity you need and more.
  • Be paid to generate energy
    If eligible, you’ll get payments from the Feed In Tariff for all the electricity you generate, as well as for any surplus electricity you sell back to the grid.
  • Cheap heating and hot water
    A hydro system may generate more electricity than you need for lighting your home and powering your electrical appliances – so you can use the excess to heat your home and your hot water too. 
  • A cheaper option for off-grid homes
    Installing a hydro system can be expensive, but in many cases it’s less than the cost of getting a connection to the National 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 water course running nearby. Assessing a hydro site properly is a job for a professional. If you think you might have a suitable site the next step is to contact a certificated installer, who will have a look at your site for you.

To be suitable for electricity generation, a river needs to have a combination of

  • flow – how much water is flowing down the river per second, and
  • head – a difference in height over a reasonably short distance

You could have either lots of flow and not much head (such as a river flowing over a weir) or lots of head and not much flow (such as a mountain stream).

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 is in flood.