Hydropower

Hydropower

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Undershot water wheels on the Orontes River in Hama, Syria

Saint Anthony Falls

Energy Portal

Hydropower is the capture of the energy of moving water for some useful purpose. Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, milling of grain, textile manufacture, and the operation of sawmills. The energy of moving water has been exploited for centuries; in Imperial Rome, water powered mills produced flour from grain, and 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 metre) drop in the Mississippi River. The mills contributed to the growth of Minneapolis. Today the largest use of hydropower is for electric power generation, which allows low cost energy to be used at long distances from the watercourse.

Contents

[hide]

 1 Types of water power

o 1.1 Hydroelectric power

o 1.2 Tidal power

 1.2.1 Tidal stream power

o 1.3 Wave power

 2 Physics

 3 Small scale hydro power

 4 See also

 5 References

 6 External links

[edit] Types of water power

There are many forms of water power:

 Waterwheels , used for hundreds of years to power mills and machinery

 Hydroelectric energy, a term usually reserved for hydroelectric dams.

 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

[edit] Hydroelectric power

Main article: Hydroelectricity

Hydraulic turbine and electrical generator.

Hydroelectric power now supplies about 715,000 MWe or 19% of world electricity (16% in 2003). Large dams are still being designed. Apart from a few countries with an abundance of it, hydro power is normally applied to peak load demand because it is readily stopped and started. Nevertheless, hydroelectric power is probably not a major option for the future of energy production in the developed nations because most major sites within these nations are either already being exploited or are unavailable for other reasons, such as environmental considerations.

Hydropower produces essentially no carbon dioxide or other harmful emissions, in contrast to burning fossil fuels, and is not a significant contributor to global warming through CO2.

Hydroelectric power can be far less expensive than electricity generated from fossil fuel or nuclear energy. Areas with abundant hydroelectric power attract industry. Environmental concerns about the effects of reservoirs may prohibit development of economic hydropower sources.

The chief advantage of hydroelectric dams is their ability to handle seasonal (as well as daily) high peak loads. When the electricity demands drop, the dam simply stores more water (which provides more flow when it releases). Some electricity generators use water dams to store excess energy (often during the night), by using the electricity to pump water up into a basin. Electricity can be generated when demand increases. In practice the utilization of stored water in river dams is sometimes