Energy in water can be harnessed and used. Since water is about 800 times denser than air, even a slow flowing
stream of water, or moderate sea swell, can yield considerable amounts of energy. There are many forms of water energy.
Hydroelectric energy is a term usually reserved for large-scale hydroelectric dams. The largest of which is the Three
Gorges Dam in China and a smaller example is The Akosombo Dam in Ghana. Micro hydro systems are hydroelectric
power installations that typically produce up to 100 kW of power. They are often used in water rich areas as a remotearea
power supply (RAPS). Run-of-the-river hydroelectricity systems derive kinetic energy from rivers and oceans
without the creation of a large reservoir.