Hydroelectric Renewable Energy:
Hydropower, hydraulic power or water power is power that is derived from the force or energy of moving water, which may be harnessed for useful purposes.
Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, sawmills, dock cranes, and domestic lifts.
Hydropower has been used for hundreds of years. In India, water wheels and watermills were built; in Imperial Rome, water powered mills produced flour from grain, and were also used for sawing timber and stone. The power of a wave of water released from a tank was used for extraction of metal ores in a method known as hushing. Hushing was widely used in Britain in the Medieval and later periods to extract lead and tin ores. It later evolved into hydraulic mining when used during the California gold rush.
In China and the rest of the Far East, hydraulically operated "pot wheel" pumps raised water into irrigation canals. In the 1830s, at the peak of the canal-building era, hydropower was used to transport barge traffic up and down steep hills using inclined plane railroads. Direct mechanical power transmission required that industries using hydropower had to locate near the waterfall. For example, during the last half of the 19th century, many grist mills were built at Saint Anthony Falls, utilizing the 50 foot (15 m) drop in the Mississippi River. The mills contributed to the growth of Minneapolis.
There are several forms of water power currently in use or development. Some are purely mechanical but many primarily generate electricity. Broad categories include:
- Waterwheels, used for hundreds of years to power mills and machinery
- Hydroelectricity, usually referring to hydroelectric dams, or run-of-the-river setups (eg hydroelectric-powered watermills)
- Damless hydro, which captures the kinetic energy in rivers, streams and oceans
- Vortex power, which creates vortices which can then be tapped for energy
- Tidal power, which captures energy from the tides in horizontal direction
- Tidal stream power, which does the same vertically
- Wave power, which uses the energy in waves
- Osmotic power, which channels river water into a container separated from sea water by a semipermeable membrane.
- Marine current power which captures the kinetic energy from marine currents.
- Ocean thermal energy conversion which exploits the temperature difference between deep and shallow waters.
Source: Wikipedia
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