The movement of water flowing down a river or hill powers a turbine which creates electricity.
- Large hydro-power projects capture water behind a dam and release it progressively to create a continuous stream of water from which the kinetic energy is captured. (Kinetic energy is the energy possessed by an object or fluid by virtue of its motion.)
- Hydro-power produces one fifth to one sixth of all the world’s electricity.
- Hydro-power makes up over 90% of electrical output from renewable sources.
- Scotland generates around 11% of its electricity from hydro sources!
- Canada, the USA and China are the three largest generators of hydro electricity.
- Brazil is also one of the world’s leading producers of hydroelectric power, with a current capacity of about 58,000 megawatts and hydroelectric providing 92% of the nation’s electricity.
- Worldwide there are literally hundreds of thousands of micro-hydropower sites (up to 100 kW) that could be developed to supply environmentally friendly renewable energy.
- Once the dam is built, the energy is virtually free.
- Little waste or pollution is produced.
- Much more reliable than wind, solar or wave power as the water flow can be controlled.
- Additional water can be stored behind a dam for use during peak times. The concept is known as pump-storage, where surplus electricity is used to pump water back uphill for release later.
- It is very efficient, with large scale hydroelectric plants reaching energy conversion levels of 90%.
- Dams are very expensive to build.
- Building a large dam will flood a very large area upstream, causing problems for animals that used to live there.
- Finding a suitable site can be difficult – the impact on residents and the environment may be unacceptable.
- Hydroelectric power sites are often remote which leads to higher distribution costs.
- Small scale projects for homes and businesses.
- Small hydro installations on River Don being refurbished.