Scottish Power Renewables Whitelee Windfarm visitor centre

Using water to create energy is something that has been done for years.

Early technology enabled the power of water to be used in mills to crush grains to make flour but this technology is now much more advanced.

Frequently Asked Questions

What is hydro electricity?

Hydro is the name given to electricity that is generated by running water (a river or a stream). Did you know the word ‘hydro’ is taken from the Greek word for water?

How does hydro work?

To generate electricity, water runs through a turbine. This causes the turbine to move and as it moves it creates power. A generator then turns this power into electricity.

How fast must the running water flow to generate electricity?

The faster water flows, the more power it has and the more powerful the water is, the more electricity it will generate.
Sometimes rivers and streams may not flow fast enough to generate electricity but this can be overcome by building a dam.

Dams are large walls that are built to store water. By storing water, controlled amounts of it can be released to flow through turbines and create electricity. Being able to control the amount of water released means that it is easier to achieve a constant and steady supply of electricity. When electricity is in demand more water can be released and when demand is lower, less water is released.

Is hydro renewable?

Yes, hydro is a renewable form of generating electricity. The heat emitted by the sun causes seawater to evaporate. The evaporated water then forms into clouds and these move inland. The clouds eventually burst and water is released as rain. This falls into our rivers and is collected by dams that release the water to produce electricity. After the water has passed through the dam is continues to flow down the river’s course where it will ultimately reach the sea and the whole cycle starts again!

What countries use hydro power?

Lots of countries use hydropower to generate electricity but some use it more than others. China, Canada, Brazil and America are all countries that have a well-established electricity supply originating from hydro.

What are the advantages to hydro?

The main advantage to hydro is that water is a free and renewable form of energy. It also doesn’t pollute and there are no waste materials. As dams store water they can react quickly to the change in demand for energy.

What are the disadvantages to hydro?

Although there are lots of rivers not all of them are suitable for generating hydro-electricity as the locations of dams are limited by the geography of the land. Dams are expensive to build and as they store water there is a risk of flooding. Water may be a renewable source but building dams creates carbon emissions (from construction) and the environmental impact depends on the size of the dam.

Related Information


Do you know that then tides are powerful enough to generate electricity? 



Generating electricity from the power of waves is an exciting and new possibility.



Plants, crops and waste can all be used to create electricity. Want to know more? 



Do you know how to generate electricty from the rays of the sun?