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93-1184: The system transfers electric power generated by several hydroelectric power stations along the Nelson River in Northern Manitoba across the wilderness to the populated areas in the south. It includes two rectifier stations, Radisson Converter Station near Gillam at 56°21′41″N 94°36′48″W  /  56.36139°N 94.61333°W  / 56.36139; -94.61333  ( Radisson Converter Station ) and Henday Converter Station near Sundance at 56°30′14″N 94°08′24″W  /  56.50389°N 94.14000°W  / 56.50389; -94.14000  ( Henday Converter Station ) , one inverter station , Dorsey Converter Station at Rosser located 26 kilometres (16 mi) north west of Winnipeg at 49°59′34″N 97°25′42″W  /  49.99278°N 97.42833°W  / 49.99278; -97.42833  ( Dorsey Converter Station ) ), and two sets of high-voltage direct current transmission lines. Each HVDC transmission line has two parallel overhead conductors to carry

186-733: A bridge circuit . The cathode-ray oscilloscope works by amplifying the voltage and using it to deflect an electron beam from a straight path, so that the deflection of the beam is proportional to the voltage. A common voltage for flashlight batteries is 1.5 volts (DC). A common voltage for automobile batteries is 12 volts (DC). Common voltages supplied by power companies to consumers are 110 to 120 volts (AC) and 220 to 240 volts (AC). The voltage in electric power transmission lines used to distribute electricity from power stations can be several hundred times greater than consumer voltages, typically 110 to 1200 kV (AC). The voltage used in overhead lines to power railway locomotives

279-430: A capacitor ), and from an electromotive force (e.g., electromagnetic induction in a generator ). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect , and the thermoelectric effect . Since it is the difference in electric potential, it is a physical scalar quantity . A voltmeter can be used to measure

372-745: A greenhouse gas . According to the World Commission on Dams report, where the reservoir is large compared to the generating capacity (less than 100 watts per square metre of surface area) and no clearing of the forests in the area was undertaken prior to impoundment of the reservoir, greenhouse gas emissions from the reservoir may be higher than those of a conventional oil-fired thermal generation plant. In boreal reservoirs of Canada and Northern Europe, however, greenhouse gas emissions are typically only 2% to 8% of any kind of conventional fossil-fuel thermal generation. A new class of underwater logging operation that targets drowned forests can mitigate

465-463: A low-head hydro power plant with hydrostatic head of few meters to few tens of meters can be classified either as an SHP or an LHP. The other distinction between SHP and LHP is the degree of the water flow regulation: a typical SHP primarily uses the natural water discharge with very little regulation in comparison to an LHP. Therefore, the term SHP is frequently used as a synonym for the run-of-the-river power plant . The largest power producers in

558-426: A dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel -powered energy plants. However, when constructed in lowland rainforest areas, where part of

651-421: A flood and fail. Changes in the amount of river flow will correlate with the amount of energy produced by a dam. Lower river flows will reduce the amount of live storage in a reservoir therefore reducing the amount of water that can be used for hydroelectricity. The result of diminished river flow can be power shortages in areas that depend heavily on hydroelectric power. The risk of flow shortage may increase as

744-754: A ground electrode site near the Keewatinoow Converter Station at 56°34′56″N 93°57′02″W  /  56.58222°N 93.95056°W  / 56.58222; -93.95056  ( Keewatinoow Ground Electrode ) connected by a 30 km electrode line. At the southern Riel Converter Station, the electrode line runs about 26 km to a grounding electrode site at 49°56′12″N 96°43′01″W  /  49.93667°N 96.71694°W  / 49.93667; -96.71694  ( Hazelridge Ground Electrode ) near Hazelridge, Manitoba . Download coordinates as: Hydroelectric Hydroelectricity , or hydroelectric power ,

837-809: A large natural height difference between two waterways, such as a waterfall or mountain lake. A tunnel is constructed to take water from the high reservoir to the generating hall built in a cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway. A simple formula for approximating electric power production at a hydroelectric station is: P = − η   ( m ˙ g   Δ h ) = − η   ( ( ρ V ˙ )   g   Δ h ) {\displaystyle P=-\eta \ ({\dot {m}}g\ \Delta h)=-\eta \ ((\rho {\dot {V}})\ g\ \Delta h)} where Efficiency

930-451: A larger amount of methane than those in temperate areas. Like other non-fossil fuel sources, hydropower also has no emissions of sulfur dioxide, nitrogen oxides, or other particulates. Reservoirs created by hydroelectric schemes often provide facilities for water sports , and become tourist attractions themselves. In some countries, aquaculture in reservoirs is common. Multi-use dams installed for irrigation support agriculture with

1023-462: A maximum clearance to ground level of 34 meters, with a minimum of 13.2 meters at mid span and maximum conductor sag. The top of the towers carries an optical ground cable providing grounding interconnection for the towers and optical fibers for control and communication of the system. Typically the right-of-way for the HVDC line is 66 meters, with 45 meters cleared directly below the line. The system

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1116-457: A maximum power of 1800 MW at a potential of ±500 kV. Bipole 2 consists of four 12-pulse converter groups at each end (two in series per pole) and was put into service in two stages. After the first stage in 1978 the maximum power was 900 MW at 250 kV, which increased to its present figure when it was completed in 1985. Bipole 2 crosses Nelson River at 56.459811 N 94.143273 W. There is a backup crossing of Nelson River at 56.441383 N 94.176114 W. It

1209-592: A positive risk adjusted return, unless appropriate risk management measures are put in place. While many hydroelectric projects supply public electricity networks, some are created to serve specific industrial enterprises. Dedicated hydroelectric projects are often built to provide the substantial amounts of electricity needed for aluminium electrolytic plants, for example. The Grand Coulee Dam switched to support Alcoa aluminium in Bellingham, Washington , United States for American World War II airplanes before it

1302-548: A relatively constant water supply. Large hydro dams can control floods, which would otherwise affect people living downstream of the project. Managing dams which are also used for other purposes, such as irrigation , is complicated. In 2021 the IEA called for "robust sustainability standards for all hydropower development with streamlined rules and regulations". Large reservoirs associated with traditional hydroelectric power stations result in submersion of extensive areas upstream of

1395-540: A result of climate change . One study from the Colorado River in the United States suggest that modest climate changes, such as an increase in temperature in 2 degree Celsius resulting in a 10% decline in precipitation, might reduce river run-off by up to 40%. Brazil in particular is vulnerable due to its heavy reliance on hydroelectricity, as increasing temperatures, lower water flow and alterations in

1488-448: A small TV/radio). Even smaller turbines of 200–300 W may power a few homes in a developing country with a drop of only 1 m (3 ft). A Pico-hydro setup is typically run-of-the-river , meaning that dams are not used, but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before returning it to the stream. An underground power station is generally used at large facilities and makes use of

1581-455: A source of low-cost renewable energy. Alternatively, small hydro projects may be built in isolated areas that would be uneconomic to serve from a grid, or in areas where there is no national electrical distribution network. Since small hydro projects usually have minimal reservoirs and civil construction work, they are seen as having a relatively low environmental impact compared to large hydro. This decreased environmental impact depends strongly on

1674-414: A start-up time of the order of a few minutes. Although battery power is quicker its capacity is tiny compared to hydro. It takes less than 10 minutes to bring most hydro units from cold start-up to full load; this is quicker than nuclear and almost all fossil fuel power. Power generation can also be decreased quickly when there is a surplus power generation. Hence the limited capacity of hydropower units

1767-581: A total of 1,500 terawatt-hours (TWh) of electrical energy in one full cycle" which was "about 170 times more energy than the global fleet of pumped storage hydropower plants". Battery storage capacity is not expected to overtake pumped storage during the 2020s. When used as peak power to meet demand, hydroelectricity has a higher value than baseload power and a much higher value compared to intermittent energy sources such as wind and solar. Hydroelectric stations have long economic lives, with some plants still in service after 50–100 years. Operating labor cost

1860-423: A well-defined voltage between nodes in the circuit, since the electric force is not a conservative force in those cases. However, at lower frequencies when the electric and magnetic fields are not rapidly changing, this can be neglected (see electrostatic approximation ). The electric potential can be generalized to electrodynamics, so that differences in electric potential between points are well-defined even in

1953-557: A year's worth of rain fell within 24 hours (see 1975 Banqiao Dam failure ). The resulting flood resulted in the deaths of 26,000 people, and another 145,000 from epidemics. Millions were left homeless. The creation of a dam in a geologically inappropriate location may cause disasters such as 1963 disaster at Vajont Dam in Italy, where almost 2,000 people died. Potential difference Voltage , also known as (electrical) potential difference , electric pressure , or electric tension

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2046-435: Is electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity , almost 4,210 TWh in 2023, which is more than all other renewable sources combined and also more than nuclear power . Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has

2139-452: Is hydroelectric power on a scale serving a small community or industrial plant. The definition of a small hydro project varies but a generating capacity of up to 10 megawatts (MW) is generally accepted as the upper limit. This may be stretched to 25 MW and 30 MW in Canada and the United States. Small hydro stations may be connected to conventional electrical distribution networks as

2232-468: Is a well-defined voltage across the inductor's terminals. This is the reason that measurements with a voltmeter across an inductor are often reasonably independent of the placement of the test leads. The volt (symbol: V ) is the derived unit for electric potential , voltage, and electromotive force . The volt is named in honour of the Italian physicist Alessandro Volta (1745–1827), who invented

2325-548: Is affected by thermodynamics. The quantity measured by a voltmeter is the negative of the difference of the electrochemical potential of electrons ( Fermi level ) divided by the electron charge and commonly referred to as the voltage difference, while the pure unadjusted electrostatic potential (not measurable with a voltmeter) is sometimes called Galvani potential . The terms "voltage" and "electric potential" are ambiguous in that, in practice, they can refer to either of these in different contexts. The term electromotive force

2418-635: Is also usually low, as plants are automated and have few personnel on site during normal operation. Where a dam serves multiple purposes, a hydroelectric station may be added with relatively low construction cost, providing a useful revenue stream to offset the costs of dam operation. It has been calculated that the sale of electricity from the Three Gorges Dam will cover the construction costs after 5 to 8 years of full generation. However, some data shows that in most countries large hydropower dams will be too costly and take too long to build to deliver

2511-427: Is between 12 kV and 50 kV (AC) or between 0.75 kV and 3 kV (DC). Inside a conductive material, the energy of an electron is affected not only by the average electric potential but also by the specific thermal and atomic environment that it is in. When a voltmeter is connected between two different types of metal, it measures not the electrostatic potential difference, but instead something else that

2604-480: Is capable of transmitting 2000 megawatts from the Nelson River stations to loads in the south. Although normally each of the lines run as bipolar systems, if a pole is shut down for maintenance or a fault, the ground return electrode is used to maintain partial capacity operation. Bipoles 1 and 2 share a ground electrode of ring type, 305 metres (1,001 ft) in diameter, 21.9 kilometres (13.6 mi) from

2697-417: Is defined so that negatively charged objects are pulled towards higher voltages, while positively charged objects are pulled towards lower voltages. Therefore, the conventional current in a wire or resistor always flows from higher voltage to lower voltage. Historically, voltage has been referred to using terms like "tension" and "pressure". Even today, the term "tension" is still used, for example within

2790-470: Is highest in the winter when solar energy is at a minimum. Pico hydro is hydroelectric power generation of under 5 kW . It is useful in small, remote communities that require only a small amount of electricity. For example, the 1.1 kW Intermediate Technology Development Group Pico Hydro Project in Kenya supplies 57 homes with very small electric loads (e.g., a couple of lights and a phone charger, or

2883-445: Is initially produced during construction of the project, and some methane is given off annually by reservoirs, hydro has one of the lowest lifecycle greenhouse gas emissions for electricity generation. The low greenhouse gas impact of hydroelectricity is found especially in temperate climates . Greater greenhouse gas emission impacts are found in the tropical regions because the reservoirs of power stations in tropical regions produce

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2976-462: Is not an energy source, and appears as a negative number in listings. Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that only the water coming from upstream is available for generation at that moment, and any oversupply must pass unused. A constant supply of water from a lake or existing reservoir upstream is a significant advantage in choosing sites for run-of-the-river. A tidal power station makes use of

3069-452: Is not generally used to produce base power except for vacating the flood pool or meeting downstream needs. Instead, it can serve as backup for non-hydro generators. The major advantage of conventional hydroelectric dams with reservoirs is their ability to store water at low cost for dispatch later as high value clean electricity. In 2021, the IEA estimated that the "reservoirs of all existing conventional hydropower plants combined can store

3162-551: Is not possible to directly switch the line to the backup crossing. Unlike Bipole 1, Bipole 2 has always been equipped with thyristors. The thyristors, supplied by the German HVDC consortium ( Siemens , AEG and Brown Boveri ) used water cooling for the first time in an HVDC project. Until that time, the relatively few HVDC schemes using thyristors had used either air cooling or, as on the Cahora Bassa project supplied by

3255-410: Is often higher (that is, closer to 1) with larger and more modern turbines. Annual electric energy production depends on the available water supply. In some installations, the water flow rate can vary by a factor of 10:1 over the course of a year. Hydropower is a flexible source of electricity since stations can be ramped up and down very quickly to adapt to changing energy demands. Hydro turbines have

3348-552: Is the joule per coulomb , where 1 volt = 1 joule (of work) per 1 coulomb of charge. The old SI definition for volt used power and current ; starting in 1990, the quantum Hall and Josephson effect were used, and in 2019 physical constants were given defined values for the definition of all SI units. Voltage is denoted symbolically by Δ V {\displaystyle \Delta V} , simplified V , especially in English -speaking countries. Internationally,

3441-484: Is the difference in electric potential between two points. In a static electric field , it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the volt (V) . The voltage between points can be caused by the build-up of electric charge (e.g.,

3534-530: Is the intensity of the electric field. In this case, the voltage increase from point A to point B is equal to the work done per unit charge, against the electric field, to move the charge from A to B without causing any acceleration. Mathematically, this is expressed as the line integral of the electric field along that path. In electrostatics, this line integral is independent of the path taken. Under this definition, any circuit where there are time-varying magnetic fields, such as AC circuits , will not have

3627-450: Is the sum of the voltage between A and B and the voltage between B and C . The various voltages in a circuit can be computed using Kirchhoff's circuit laws . When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage. Instantaneous voltages can be added for direct current (DC) and AC, but average voltages can be meaningfully added only when they apply to signals that all have

3720-679: The Bonneville Dam in 1937 and being recognized by the Flood Control Act of 1936 as the premier federal flood control agency. Hydroelectric power stations continued to become larger throughout the 20th century. Hydropower was referred to as "white coal". Hoover Dam 's initial 1,345 MW power station was the world's largest hydroelectric power station in 1936; it was eclipsed by the 6,809 MW Grand Coulee Dam in 1942. The Itaipu Dam opened in 1984 in South America as

3813-549: The Industrial Revolution would drive development as well. In 1878, the world's first hydroelectric power scheme was developed at Cragside in Northumberland , England, by William Armstrong . It was used to power a single arc lamp in his art gallery. The old Schoelkopf Power Station No. 1 , US, near Niagara Falls , began to produce electricity in 1881. The first Edison hydroelectric power station,

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3906-806: The International Exhibition of Hydropower and Tourism , with over one million visitors 1925. By 1920, when 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land and water. As the power stations became larger, their associated dams developed additional purposes, including flood control , irrigation and navigation . Federal funding became necessary for large-scale development, and federally owned corporations, such as

3999-633: The Tennessee Valley Authority (1933) and the Bonneville Power Administration (1937) were created. Additionally, the Bureau of Reclamation which had begun a series of western US irrigation projects in the early 20th century, was now constructing large hydroelectric projects such as the 1928 Hoover Dam . The United States Army Corps of Engineers was also involved in hydroelectric development, completing

4092-583: The Vulcan Street Plant , began operating September 30, 1882, in Appleton, Wisconsin , with an output of about 12.5 kilowatts. By 1886 there were 45 hydroelectric power stations in the United States and Canada; and by 1889 there were 200 in the United States alone. At the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble , France held

4185-506: The potential energy of dammed water driving a water turbine and generator . The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head . A large pipe (the " penstock ") delivers water from the reservoir to the turbine. This method produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand,

4278-430: The voltaic pile , possibly the first chemical battery . A simple analogy for an electric circuit is water flowing in a closed circuit of pipework , driven by a mechanical pump . This can be called a "water circuit". The potential difference between two points corresponds to the pressure difference between two points. If the pump creates a pressure difference between two points, then water flowing from one point to

4371-400: The water frame , and continuous production played a significant part in the development of the factory system, with modern employment practices. In the 1840s, hydraulic power networks were developed to generate and transmit hydro power to end users. By the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand arising from

4464-409: The 1,272 MW Kettle Rapids generating station required a long transmission line to connect it to load centers in the southern part of Manitoba. The Government of Canada agreed to finance installation of an HVDC line to be repaid by Manitoba Hydro when the load growth permitted the utility to assume the debt due to the line. Delivery of direct current electric power began on June 17, 1972. One unit of

4557-498: The Bipole III system are: The line uses guyed steel towers in northern stretches of the line and self-supporting steel lattice towers in the southern part. On average there will be about two structures per kilometer. Each tower carries a bundled conductor for each pole. Each pole conductor is made of three sub-conductors equivalent to 1,590 MCM ACSR . Conductors are supported by toughened glass or porcelain strain insulators with

4650-475: The Dorsey Converter Plant at 50°10′29″N 97°24′08″W  /  50.17472°N 97.40222°W  / 50.17472; -97.40222  ( Dorsey Converter Station Ground Return Electrode ) . The Dorsey electrode is connected with the converter plant by two overhead lines on wooden poles, one for Bipole 1 and one for Bipole 2. At Radisson, Bipole 1 uses a ground electrode of

4743-463: The IEA released a main-case forecast of 141 GW generated by hydropower over 2022–2027, which is slightly lower than deployment achieved from 2017–2022. Because environmental permitting and construction times are long, they estimate hydropower potential will remain limited, with only an additional 40 GW deemed possible in the accelerated case. In 2021 the IEA said that major modernisation refurbishments are required. Most hydroelectric power comes from

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4836-574: The Kettle generating station was completed before the direct current converters were completed. For the winter of 1970 the bipole lines were energized with alternating current, contributing a useful amount of energy to the Manitoba system; a shunt reactor was installed to prevent excess voltage rise due to the Ferranti effect . At that time, Bipole I used the world's highest operating voltage to deliver

4929-464: The ability to transport particles heavier than itself downstream. This has a negative effect on dams and subsequently their power stations, particularly those on rivers or within catchment areas with high siltation. Siltation can fill a reservoir and reduce its capacity to control floods along with causing additional horizontal pressure on the upstream portion of the dam. Eventually, some reservoirs can become full of sediment and useless or over-top during

5022-595: The balance between stream flow and power production. Micro hydro means hydroelectric power installations that typically produce up to 100 kW of power. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without purchase of fuel. Micro hydro systems complement photovoltaic solar energy systems because in many areas water flow, and thus available hydro power,

5115-413: The circuit are not negligible, then their effects can be modelled by adding mutual inductance elements. In the case of a physical inductor though, the ideal lumped representation is often accurate. This is because the external fields of inductors are generally negligible, especially if the inductor has a closed magnetic path . If external fields are negligible, we find that is path-independent, and there

5208-461: The current rating to 2000 A and the voltage rating of most equipment to 166 kV per bridge (i.e., 500 kV total), although as of January 2013 Manitoba Hydro still report that the line is operated at +463 kV/−450 kV. When it was built between March 1971 and October 1977, mercury-arc valves were used to rectify the alternating current . These valves , supplied by English Electric , each had six anode columns in parallel and were

5301-404: The daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershot water wheels . Tidal power is viable in a relatively small number of locations around

5394-505: The dams, sometimes destroying biologically rich and productive lowland and riverine valley forests, marshland and grasslands. Damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and wildlife. The loss of land is often exacerbated by habitat fragmentation of surrounding areas caused by the reservoir. Hydroelectric projects can be disruptive to surrounding aquatic ecosystems both upstream and downstream of

5487-431: The device with respect to a common reference point (or ground ). The voltage drop is the difference between the two readings. Two points in an electric circuit that are connected by an ideal conductor without resistance and not within a changing magnetic field have a voltage of zero. Any two points with the same potential may be connected by a conductor and no current will flow between them. The voltage between A and C

5580-705: The effect of forest decay. Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned. In 2000, the World Commission on Dams estimated that dams had physically displaced 40–80 million people worldwide. Because large conventional dammed-hydro facilities hold back large volumes of water, a failure due to poor construction, natural disasters or sabotage can be catastrophic to downriver settlements and infrastructure. During Typhoon Nina in 1975 Banqiao Dam in Southern China failed when more than

5673-446: The electric field in the region exterior to each component is conservative, and voltages between nodes in the circuit are well-defined, where as long as the path of integration does not pass through the inside of any component. The above is the same formula used in electrostatics. This integral, with the path of integration being along the test leads, is what a voltmeter will actually measure. If uncontained magnetic fields throughout

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5766-428: The electric field, rather than to differences in electric potential. In this case, the voltage rise along some path P {\displaystyle {\mathcal {P}}} from r A {\displaystyle \mathbf {r} _{A}} to r B {\displaystyle \mathbf {r} _{B}} is given by: However, in this case the "voltage" between two points depends on

5859-525: The end of 2004 the last of the mercury arc valves in Pole 2 had been replaced by thyristors. At both Radisson and Dorsey, the thyristors are situated in the same hall where the mercury arc valves originally stood. At both locations, the hall has a height of 18.29 metres (60.0 feet), a width of 22.86 metres (75.0 feet) and a length of 44.2 metres (145 feet). The Bipole 2 transmission line runs 937 kilometres (582 mi) from Henday to Dorsey. Bipole 2 can transfer

5952-399: The excess generation capacity is used to pump water into the higher reservoir, thus providing demand side response . When the demand becomes greater, water is released back into the lower reservoir through a turbine. In 2021 pumped-storage schemes provided almost 85% of the world's 190 GW of grid energy storage and improve the daily capacity factor of the generation system. Pumped storage

6045-534: The forest is inundated, substantial amounts of greenhouse gases may be emitted. Construction of a hydroelectric complex can have significant environmental impact, principally in loss of arable land and population displacement. They also disrupt the natural ecology of the river involved, affecting habitats and ecosystems, and siltation and erosion patterns. While dams can ameliorate the risks of flooding, dam failure can be catastrophic. In 2021, global installed hydropower electrical capacity reached almost 1,400 GW,

6138-404: The government's claims for why the line must be built down the west side of the province. The line was constructed on the western route and completed in 2018. The transmission system is currently composed of three bipole transmission lines with their converter stations and ground return electrodes to enable monopole operation. Bipole 1 runs 895 kilometres (556 mi) from Radisson to Dorsey. It

6231-506: The highest among all renewable energy technologies. Hydroelectricity plays a leading role in countries like Brazil, Norway and China. but there are geographical limits and environmental issues. Tidal power can be used in coastal regions. China added 24 GW in 2022, accounting for nearly three-quarters of global hydropower capacity additions. Europe added 2 GW, the largest amount for the region since 1990. Meanwhile, globally, hydropower generation increased by 70 TWh (up 2%) in 2022 and remains

6324-469: The largest amount of power from a remote site to a city, and employed the largest mercury arc valves ever developed for such an application. The line required construction of over 3,900 guyed towers and 96 self-supporting towers across varied terrain. Permafrost in some areas led to foundation settling of up to 3 feet (1 m). The loan by the Government of Canada was discharged when Manitoba Hydro bought

6417-519: The largest renewable energy source, surpassing all other technologies combined. Hydropower has been used since ancient times to grind flour and perform other tasks. In the late 18th century hydraulic power provided the energy source needed for the start of the Industrial Revolution . In the mid-1700s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique , which described vertical- and horizontal-axis hydraulic machines, and in 1771 Richard Arkwright 's combination of water power ,

6510-750: The largest, producing 14 GW , but was surpassed in 2008 by the Three Gorges Dam in China at 22.5 GW . Hydroelectricity would eventually supply some countries, including Norway , Democratic Republic of the Congo , Paraguay and Brazil , with over 85% of their electricity. In 2021 the International Energy Agency (IEA) said that more efforts are needed to help limit climate change . Some countries have highly developed their hydropower potential and have very little room for growth: Switzerland produces 88% of its potential and Mexico 80%. In 2022,

6603-664: The line and outstanding debt in 1992. In 1997 a tornado damaged 19 towers of the DC lines. During repairs, some major customers were advised to curtail load, but imports over the 500 kV lines from adjacent utilities in the United States prevented serious interruption of power. A third such line, called Bipole 3 was proposed, to run along the west side of Manitoba. On October 26, 2009, the Canadian Taxpayers Federation , along with engineering and environmental experts, released an analysis which they claimed refuted each of

6696-487: The most powerful mercury arc valves ever built. Each of them had a weight of 10,200 kg (22,500 lb), a length of 4.57 metres (15.0 feet), a width of 2.44 metres (8.0 feet) and a height of 3.96 metres (13.0 feet). Between 1992 and 1993 the mercury arc valves of Pole 1 were replaced with solid state thyristors from GEC Alsthom, increasing the maximum power and voltage of the line to its current levels. The mercury arc valves of Pole 2 were replaced later by Siemens . By

6789-407: The other will be able to do work, such as driving a turbine . Similarly, work can be done by an electric current driven by the potential difference provided by a battery . For example, the voltage provided by a sufficiently-charged automobile battery can "push" a large current through the windings of an automobile's starter motor . If the pump is not working, it produces no pressure difference, and

6882-424: The path taken. In circuit analysis and electrical engineering , lumped element models are used to represent and analyze circuits. These elements are idealized and self-contained circuit elements used to model physical components. When using a lumped element model, it is assumed that the effects of changing magnetic fields produced by the circuit are suitably contained to each element. Under these assumptions,

6975-697: The phrase " high tension " (HT) which is commonly used in thermionic valve ( vacuum tube ) based and automotive electronics. In electrostatics , the voltage increase from point r A {\displaystyle \mathbf {r} _{A}} to some point r B {\displaystyle \mathbf {r} _{B}} is given by the change in electrostatic potential V {\textstyle V} from r A {\displaystyle \mathbf {r} _{A}} to r B {\displaystyle \mathbf {r} _{B}} . By definition, this is: where E {\displaystyle \mathbf {E} }

7068-633: The plant site. Generation of hydroelectric power changes the downstream river environment. Water exiting a turbine usually contains very little suspended sediment, which can lead to scouring of river beds and loss of riverbanks. The turbines also will kill large portions of the fauna passing through, for instance 70% of the eel passing a turbine will perish immediately. Since turbine gates are often opened intermittently, rapid or even daily fluctuations in river flow are observed. Drought and seasonal changes in rainfall can severely limit hydropower. Water may also be lost by evaporation. When water flows it has

7161-430: The points across which the voltage is measured. When using a voltmeter to measure voltage, one electrical lead of the voltmeter must be connected to the first point, one to the second point. A common use of the term "voltage" is in describing the voltage dropped across an electrical device (such as a resistor). The voltage drop across the device can be understood as the difference between measurements at each terminal of

7254-417: The positive and negative feeds. A third line, Bipole 3, was completed in 2018, running from the new Keewatinoow Converter Station along the west side of Lake Manitoba to the new Riel Converter station on the east side of Winnipeg. There are no intermediate switching stations or taps. All three bipolar systems have extensive ground return electrodes to allow use in monopolar mode. Construction in 1966 of

7347-414: The presence of time-varying fields. However, unlike in electrostatics, the electric field can no longer be expressed only in terms of the electric potential. Furthermore, the potential is no longer uniquely determined up to a constant, and can take significantly different forms depending on the choice of gauge . In this general case, some authors use the word "voltage" to refer to the line integral of

7440-450: The rainfall regime, could reduce total energy production by 7% annually by the end of the century. Lower positive impacts are found in the tropical regions. In lowland rainforest areas, where inundation of a part of the forest is necessary, it has been noted that the reservoirs of power plants produce substantial amounts of methane . This is due to plant material in flooded areas decaying in an anaerobic environment and forming methane,

7533-443: The same consortium, oil-cooling. The thyristors were arranged in floor-mounted vertical stacks of four each ( quadrivalves ). Each set contained 96 thyristor levels in series, with two in parallel. These were arranged in 16 thyristor modules connected in series with 8 reactor modules. In 1996 an extreme wind effect damaged both Bipoles 1 and 2 and threatened to black out Winnipeg. Power was maintained by importing from Minnesota while

7626-415: The same frequency and phase. Instruments for measuring voltages include the voltmeter , the potentiometer , and the oscilloscope . Analog voltmeters , such as moving-coil instruments, work by measuring the current through a fixed resistor, which, according to Ohm's law , is proportional to the voltage across the resistor. The potentiometer works by balancing the unknown voltage against a known voltage in

7719-692: The same size and type as Dorsey, but only 11.2 kilometres (7.0 mi) away from the station at 56°21′22″N 94°45′17″W  /  56.35611°N 94.75472°W  / 56.35611; -94.75472  ( Radisson Converter Station Ground Return Electrode ) . Bipole 2 uses a ground electrode 548 metres (1,798 ft) in diameter, and 11.2 kilometres (7.0 mi) from the Henday Converter Station 56°26′2″N 94°13′22″W  /  56.43389°N 94.22278°W  / 56.43389; -94.22278  ( Henday Converter Station Ground Return Electrode ) . Bipole 3 has

7812-465: The symbol U is standardized. It is used, for instance, in the context of Ohm's or Kirchhoff's circuit laws . The electrochemical potential is the voltage that can be directly measured with a voltmeter. The Galvani potential that exists in structures with junctions of dissimilar materials is also work per charge but cannot be measured with a voltmeter in the external circuit (see § Galvani potential vs. electrochemical potential ). Voltage

7905-401: The turbine will not rotate. Likewise, if the automobile's battery is very weak or "dead" (or "flat"), then it will not turn the starter motor. The hydraulic analogy is a useful way of understanding many electrical concepts. In such a system, the work done to move water is equal to the " pressure drop" (compare p.d.) multiplied by the volume of water moved. Similarly, in an electrical circuit,

7998-468: The two existing Bipoles were repaired. To avoid a repetition of this event, and further improve the reliability of the power supply, Manitoba Hydro examined routes further to the west for their Bipole 3 line. The plans also include an additional converter station and feeder lines around the city. Bipole 3 construction started in 2012. The line was completed and entered service in July 2018. The main elements of

8091-400: The voltage between two points in a system. Often a common reference potential such as the ground of the system is used as one of the points. In this case, voltage is often mentioned at a point without completely mentioning the other measurement point. A voltage can be associated with either a source of energy or the loss, dissipation, or storage of energy. The SI unit of work per unit charge

8184-465: The work done to move electrons or other charge carriers is equal to "electrical pressure difference" multiplied by the quantity of electrical charges moved. In relation to "flow", the larger the "pressure difference" between two points (potential difference or water pressure difference), the greater the flow between them (electric current or water flow). (See " electric power ".) Specifying a voltage measurement requires explicit or implicit specification of

8277-524: The world are hydroelectric power stations, with some hydroelectric facilities capable of generating more than double the installed capacities of the current largest nuclear power stations . Although no official definition exists for the capacity range of large hydroelectric power stations, facilities from over a few hundred megawatts are generally considered large hydroelectric facilities. Currently, only seven facilities over 10 GW ( 10,000 MW ) are in operation worldwide, see table below. Small hydro

8370-539: The world. The classification of hydropower plants starts with two top-level categories: The classification of a plant as an SHP or LHP is primarily based on its nameplate capacity , the threshold varies by the country, but in any case a plant with the capacity of 50 MW or more is considered an LHP. As an example, for China, SHP power is below 25 MW, for India - below 15 MW, most of Europe - below 10 MW. The SHP and LHP categories are further subdivided into many subcategories that are not mutually exclusive. For example,

8463-586: Was allowed to provide irrigation and power to citizens (in addition to aluminium power) after the war. In Suriname , the Brokopondo Reservoir was constructed to provide electricity for the Alcoa aluminium industry. New Zealand 's Manapouri Power Station was constructed to supply electricity to the aluminium smelter at Tiwai Point . Since hydroelectric dams do not use fuel, power generation does not produce carbon dioxide . While carbon dioxide

8556-617: Was first used by Volta in a letter to Giovanni Aldini in 1798, and first appeared in a published paper in 1801 in Annales de chimie et de physique . Volta meant by this a force that was not an electrostatic force, specifically, an electrochemical force. The term was taken up by Michael Faraday in connection with electromagnetic induction in the 1820s. However, a clear definition of voltage and method of measuring it had not been developed at this time. Volta distinguished electromotive force (emf) from tension (potential difference):

8649-440: Was originally rated to run at a maximum potential difference of ±450 kilovolts and a maximum power of 1620 megawatts . This results in an electric current of 1800 Amperes . Bipole 1 consists of six, 6-pulse converter groups at each end (three in series per pole), each originally rated at 150 kV DC, 1800 A. Each converter group can be bridged at the DC side with a vacuum switch. Subsequent upgrades have increased

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