Hydropower or hydraulic power is the force or energy of moving water. A water wheel is a means of extracting power from the flow (or fall of water otherwise known as Hydropower. See Orontid dynasty for the Armenian kings and satraps called Orontes Hama (ancient Hamath; Arabic: حماة meaning fortress is a city on the banks of the Orontes river in central Syria north of Syria ( سوريّة or) officially the Syrian Arab Republic (Arabic ar الجمهورية العربية السورية In Physics, a force is whatever can cause an object with Mass to Accelerate. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός It may be captured for some useful purpose.
Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, and sawmills. Electric power is defined as the rate at which Electrical energy is transferred by an Electric circuit. Irrigation is an artificial application of water to the soil usually for assisting in growing crops This article is about a type of structure For other locational uses see Milldam. A textile is a flexible material comprised of a network of natural or artificial Fibres often referred to as thread or Yarn. A sawmill is a facility where logs are cut into boards Sawmill process A sawmill's basic operation is much like those of 100 years ago a log enters A trompe produces compressed air from falling water, which could then be used to power other machinery at a distance from the water. A trompe is a water-powered Gas compressor, commonly used before the advent of the electric-powered compressor
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History
Hydropower has been used for hundreds of years. Saint Anthony Falls, or the Falls of Saint Anthony, located northeast of downtown Minneapolis Minnesota, was the only natural major Waterfall on the 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. This article is about the history of South Asia prior to the Partition of British India in 1947 A water wheel is a means of extracting power from the flow (or fall of water otherwise known as Hydropower. This article is about a type of structure For other locational uses see Milldam. The Roman Empire was the post-Republican phase of the ancient Roman civilization, characterised by an autocratic form of government and large territorial 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 is an ancient Mining method using a flood or torrent of water to reveal mineral veins Hushing was widely used in Britain in the Medieval and later periods to extract lead and tin ores. See also Kingdom of Great Britain Great Britain (Breatainn Mhòr Prydain Fawr Breten Veur Graet Breetain is the larger of the two main islands Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 It later evolved into hydraulic mining when used during the California gold rush. Hydraulic mining, or hydraulicking, is a form of Mining that employs Water to dislodge rock material or move sediment The California Gold Rush (1848&ndash1855 began on January 24 1848 when Gold was discovered by James Marshall at Sutter's Mill in Coloma, California
In China and the rest of the Far East, hydraulically operated "pot wheel" pumps raised water into irrigation canals. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National 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. Canals are artificial channels for water There are two types of canals water conveyance canals which are used for the conveyance and delivery of water and Waterways BARGE, the Big August RecGambling Excursion is a yearly convention held in Las Vegas during the first weekend of August A funicular, also known as a funicular railway, incline, inclined railway, inclined plane, or cliff railway, is a type of self-contained Direct mechanical power transmission required that industries using hydropower had to locate near the waterfall. Power transmission is the movement of Energy from its place of generation to a location where it is applied to performing useful work. 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. A gristmill or grist mill is a building where Grain is ground into Flour, or the grinding mechanism itself Saint Anthony Falls, or the Falls of Saint Anthony, located northeast of downtown Minneapolis Minnesota, was the only natural major Waterfall on the The Mississippi River is the second longest River in the United States, with a length of from its source in Lake Itasca in Minnesota to The mills contributed to the growth of Minneapolis. Hydraulic power networks also existed, using pipes carrying pressurized liquid to transmit mechanical power from a power source, such as a pump, to end users. A hydraulic power network is a system of interconnected pipes carrying Pressurized liquid used to transmit mechanical power from a Power source
Today the largest use of hydropower is for the creation of hydroelectricity, which allows low cost energy to be used at long distances from the water source. Hydroelectricity is electricity generated by Hydropower, ie the production of power through use of the gravitational force of falling water
Natural manifestations
In hydrology, hydropower is manifested in the force of the water on the riverbed and banks of a river. Hydrology (from Greek Yδωρ hudōr, "water" and λόγος logos, "study" is the study of the movement distribution and quality of It is particularly powerful when the river is in flood. The force of the water results in the removal of sediment and other materials from the riverbed and banks of the river, causing erosion and other alterations. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind
Types
There are several forms of water power:
- 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). A water wheel is a means of extracting power from the flow (or fall of water otherwise known as Hydropower. Hydroelectricity is electricity generated by Hydropower, ie the production of power through use of the gravitational force of falling water
- Damless hydro, which captures the kinetic energy in rivers, streams and oceans. Damless hydro or Damless hydro-electric is a renewable technology based on capturing the kinetic energy of rivers channels of chutes spillways irrigation systems tides and
- Tidal power, which captures energy from the tides in horizontal direction
- Tidal stream power, which does the same vertically
- Vortex power, which creates vortices which can then be tapped for energy
- Wave power, which uses the energy in waves
Hydroelectric power
Hydroelectric power now supplies about 715,000 MWe or 19% of world electricity (16% in 2003). The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. Large dams are still being designed. The world's largest is the Three Gorges Dam on the third longest river in the world, the Yangtzi River. Zh-yue三峽大壩 The Three Gorges Dam ( is a hydroelectric River Dam that spans the Yangtze River in Sandouping, Apart from a few countries with an abundance of hydro power, this energy source is normally applied to peak load demand, because it is readily stopped and started. It is also provides a high-capacity, low-cost means of energy storage, known as "pumped storage". Hydro-storage redirects here For storage of water for other purposes see Reservoir.
Resources in the United States
There is a common misconception that economically developed nations have harnessed all of their available hydropower resources. In the United States, according to the US Department of Energy, "previous assessments have focused on potential projects having a capacity of 1 MW and above". The United States of America —commonly referred to as the The United States Department of Energy ( DOE) is a Cabinet -level department of the United States government responsible for energy policy This may partly explain the discrepancy. More recently, in 2004, an extensive survey was conducted by the US-DOE which counted sources under 1 MW (mean annual average), and found that only 40% of the total hydropower potential had been developed. A total of 170 GW (mean annual average) remains available for development. Of this, 34% is within the operating envelope of conventional turbines, 50% is within the operating envelope of microhydro technologies (defined as less than 100 kW), and 16% is within the operating envelope of unconventional systems. Micro Hydro is a term used for Hydroelectric power installations that typically produce up to 100 kW of power [1] In 2005, the US generated 1012 kilo-watt hours of electricity. Kilo- (symbol k is a prefix in the SI and other systems of units denoting 103 or 1000 The total undeveloped hydropower resource is equivalent to about one-third of total US electricity generation in 2005. Developed hydropower accounted for 6. 4% of total US electricity generated in 2005.
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. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Fossil fuels or mineral fuels are fossil source Fuels that is Hydrocarbons found within the top layer of the Earth’s crust.
Hydroelectric power can be far less expensive than electricity generated from fossil fuels 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 complicated by demands for irrigation which may occur out of phase with peak electrical demands.
Not all hydroelectric power requires a dam; a run-of-river project only uses part of the stream flow and is a characteristic of small hydropower projects. Small hydro is the development of Hydroelectric power on a scale serving a small community or industrial plant A developing technology example is the Gorlov helical turbine. The Gorlov helical turbine (GHT evolved from the Darrieus turbine design by altering it to have helical blades/foils
Tidal power
Harnessing the tides in a bay or estuary has been achieved in France (since 1966), Canada and Russia, and could be achieved in other areas with a large tidal range. Tidal power, sometimes called tidal energy, is a form of Hydropower that converts the energy of Tides into electricity or other useful forms of power This article is about the country For a topic outline on this subject see List of basic France topics. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending The trapped water turns turbines as it is released through the tidal barrage in either direction. A turbine is a rotary Engine that extracts Energy from a Fluid flow A possible fault is that the system would generate electricity most efficiently in bursts every six hours (once every tide). This limits the applications of tidal energy; tidal power is highly predictable but not able to follow changing electrical demand.
Tidal stream power
A relatively new technology, tidal stream generators draw energy from currents in much the same way that wind generators do. The higher density of water means that a single generator can provide significant power. This technology is at the early stages of development and will require more research before it becomes a significant contributor.
Several prototypes have shown promise. In the UK in 2003, a 300 kW Periodflow marine current propeller type turbine was tested off the coast of Devon, and a 150 kW oscillating hydroplane device, the Stingray, was tested off the Scottish coast. Another British device, the Hydro Venturi, is to be tested in San Francisco Bay.
The Canadian company Blue Energy has plans for installing very large arrays tidal current devices mounted in what they call a 'tidal fence' in various locations around the world, based on a vertical axis turbine design.
Wave power
Harnessing power from ocean surface wave motion might yield much more energy than tides. Wave power refers to the Energy of Ocean surface waves and the capture of that energy to do useful work — including Electricity generation, Ocean surface waves are Surface waves that occur on the Free surface of the Ocean. The feasibility of this has been investigated, particularly in Scotland in the UK. Generators either coupled to floating devices or turned by air displaced by waves in a hollow concrete structure would produce electricity. In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic Numerous technical problems have frustrated progress.
A prototype shore based wave power generator is being constructed at Port Kembla in Australia and is expected to generate up to 500 MWh annually. Port Kembla is a Seaport, industrial complex (one of the largest in Australia and suburb of Wollongong, in the Illawarra region of New South Wales For a topic outline on this subject see List of basic Australia topics. The Wave Energy Converter has been constructed (as of July 2005) and initial results have exceeded expectations of energy production during times of low wave energy. Wave energy is captured by an air driven generator and converted to electricity. For countries with large coastlines and rough sea conditions, the energy of waves offers the possibility of generating electricity in utility volumes. Excess power during rough seas could be used to produce hydrogen.
Physics
A hydropower resource can be measured according to the amount of available power, or energy per unit time. In Physics, power (symbol P) is the rate at which work is performed or energy is transmitted or the amount of energy required or expended for In large reservoirs, the available power is generally only a function of the hydraulic head and rate of fluid flow. Hydraulic head is a specific measurement of water pressure or Total energy per Unit weight above a Geodetic datum. The volumetric flow rate in Fluid dynamics and Hydrometry, (also known as volume flow rate or rate of fluid flow) is the volume of fluid which In a reservoir, the head is the height of water in the reservoir relative to its height after discharge. Each unit of water can do an amount of work equal to its weight times the head.
The amount of energy 
released by lowering an object of mass 
by a height 
in a gravitational field is
where 
is the acceleration due to gravity.
The energy available to hydroelectric dams is the energy that can be liberated by lowering water in a controlled way. Hydroelectricity is electricity generated by Hydropower, ie the production of power through use of the gravitational force of falling water In these situations, the power is related to the mass flow rate. Mass flow rate is the movement of Mass per Time. Its unit is mass divided by Time, so Kilogram per Second in SI
Substituting 
for 
and expressing 
in terms of the volume of liquid moved per unit time (the rate of fluid flow 
) and the density of water, we arrive at the usual form of this expression:
For in watts, 
is measured in kg/m³, is measured in m³/s, (gee) is measured in m/s², and is measured in metres. The volumetric flow rate in Fluid dynamics and Hydrometry, (also known as volume flow rate or rate of fluid flow) is the volume of fluid which The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. Standard gravity, usually denoted by g 0 or g n is the nominal acceleration due to gravity at the Earth's surface at sea level The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International
Some hydropower systems such as water wheels can draw power from the flow of a body of water without necessarily changing its height. A water wheel is a means of extracting power from the flow (or fall of water otherwise known as Hydropower. In this case, the available power is the kinetic energy of the flowing water. The kinetic energy of an object is the extra Energy which it possesses due to its motion
where 
is the velocity of the water,
or with 
where A is the area through which the water passes, also
Over-shot water wheels can efficiently capture both types of energy. In Physics, velocity is defined as the rate of change of Position. Area is a Quantity expressing the two- Dimensional size of a defined part of a Surface, typically a region bounded by a closed Curve.
Small scale hydro power
Small scale hydro or micro-hydro power has been increasingly used as an alternative energy source, especially in remote areas where other power sources are not viable. Small hydro is the development of Hydroelectric power on a scale serving a small community or industrial plant Micro Hydro is a term used for Hydroelectric power installations that typically produce up to 100 kW of power Small scale hydro power systems can be installed in small rivers or streams with little or no discernible environmental effect on things such as fish migration. Most small scale hydro power systems make no use of a dam or major water diversion, but rather use water wheels.
There are some considerations in a micro-hydro system installation. The amount of water flow available on a consistent basis, since lack of rain can affect plant operation. Head, or the amount of drop between the intake and the exit. The more head, the more power that can be generated. There can be legal and regulatory issues, since most countries, cities, and states have regulations about water rights and easements.
Over the last few years, the U. S. Government has increased support for alternative power generation. Many resources such as grants, loans, and tax benefits are available for small scale hydro systems.
In poor areas, many remote communities have no electricity. Micro hydro power, with a capacity of 100 kW or less, allows communities to generate electricity1. This form of power is supported by various organizations such as the UK's Practical Action. Practical Action is a development charity registered in the United Kingdom which works directly in four regions of the developing world – Latin America
Micro-hydro power can be used directly as "shaft power" for many industrial applications. Alternatively, the preferred option for domestic energy supply is to generate electricity with a generator or a reversed electric motor which, while less efficient, is likely to be available locally and cheaply.
See also
- Blue energy
- Damless hydro
- Deep lake water cooling
- Micro hydro
- Ocean thermal energy conversion
- Pico hydro
- Renewable energy
- Trompe
References
- Micro-hydro power, Adam Harvey, 2004, Intermediate Technology Development Group, retrieved 1 January 2005 from http://www.itdg.org/docs/technical_information_service/micro_hydro_power.pdf. Damless hydro or Damless hydro-electric is a renewable technology based on capturing the kinetic energy of rivers channels of chutes spillways irrigation systems tides and Deep lake water cooling uses cold water pumped from the bottom of a lake as a Heat sink for climate control systems. Micro Hydro is a term used for Hydroelectric power installations that typically produce up to 100 kW of power Ocean thermal energy conversion ( OTEC) is a method for generating electricity which uses the Temperature difference that exists between deep and shallow waters to Pico hydro is a term used for Hydroelectric power generation of under 5kW Renewable energy is Energy generated from Natural resources mdashsuch as Sunlight, Wind, Rain, tides and geothermal A trompe is a water-powered Gas compressor, commonly used before the advent of the electric-powered compressor New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar.
- Microhydropower Systems, U. S. Department of Energy, Energy Efficiency and Renewable Energy, 2005
External links
- International Centre for Hydropower (ICH) hydropower portal with links to numerous organizations related to hydropower worldwide
- Practical Action (ITDG) a UK charity developing micro-hydro power and giving extensive technical documentation.
- microhydropower.net
- Congressional Research Service (CRS) Reports regarding Hydropower
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