Energy in water (in the form of kinetic energy, temperature
differences or salinity gradients) 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. Examples are the Grand Coulee
Dam in Washington State and 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 Remote Area Power Supply (RAPS). There are
many of these installations around the world, including several
delivering around 50 kW in the Solomon Islands. Damless hydro
systems derive kinetic energy from rivers and oceans without
using a dam. Ocean energy describes all the technologies to
harness energy from the ocean and the sea. Marine current power,
similar to tidal stream power, uses the k