Hydropower is the world's leading renewable energy resource and the oldest method of harnessing clean power - the first waterwheels were used over 2,000 years ago.

It currently produces around 17% of the world's electricity and 90% of the world's renewable power.

Twenty-five countries depend on hydropower  for 90% of their electricity.

Less than one third of the world's practical hydro capacity has been developed.

There are no direct CO 2 emissions from hydro projects.

Small hydro schemes have minimum visual impact on their surrounding environment.

Hydropower, after 150 years as an electricity generating source, is still one of the most inexpensive ways to generate power.

Most large hydro stations have dams but thousands of small hydro stations don't – they are ‘run-of-river' schemes and make a minimal impact on the environment.

Hydro is the only renewable technology that can be used to store large quantities of energy in a clean environmentally-friendly way. This is done by reservoir storage and pumped storage schemes.

Hydro installations can have a useful life of over 100 years – many such plants are in existence worldwide.

A modern hydro turbine generator can convert over 90% of the energy in the available water into electricity. This is more efficient than any other form of generation.