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66-572: The Kuratau power station is a hydroelectric power facility in Kuratau on the western side of Lake Taupō in New Zealand which makes use of water from the Kuratau River . The river is impounded behind a dam to form Lake Kuratau before discharging through the power station back into the river. The scheme is operated by Trustpower on behalf of its owner King Country Energy. In 1952 Lloyd Mandeno who

132-737: 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

198-463: 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

264-426: 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

330-421: 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

396-809: 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

462-451: 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

528-586: 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

594-545: 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

660-526: 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

726-467: A result, it took until 1955 before the board was granted a licence to generate electricity at Kuratau. Further delays then occurred with obtaining the generation equipment, which had to be imported. The station's output was to be distributed over 33 kV transmission lines which had to be built. While it was not the first such line in the board's area it was the first that they contracted out for construction and as such delays were incurred in obtaining some of

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792-448: 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

858-455: 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

924-414: 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

990-581: 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

1056-410: A with drainage system under the lining and relined with concrete and shotcrete to solve excessive leakage. At the same time erosion below the spillway was repaired with shotcrete, the fastening of the powerhouse's cladding was improved and the penstock supports were strengthened. Diversion banks were also added to control flooding in the event of the bursting of a penstock or the canal and the closing of

1122-484: 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. Abutment The civil engineering term may also refer to

1188-435: 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

1254-448: 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

1320-627: 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

1386-451: Is basically a long narrow flooded river valley has a relatively small volume. This means that for example at an inflow of about four cumecs the lake will be drained in between 36 and 48 hours if the station was operated at its full output. The lake has a consented operating range of 2.61m which is typically not fully utilised during the station's day-to-day operation. Hydroelectric power Hydroelectricity , or hydroelectric power ,

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1452-541: Is embedded behind Transpower 's Ongarue Substation, but can also be switched within The Lines Company network to either Transpower's National Park or Tokaanu substations. Operation of the power station is covered by the requirements of five resource consents which expire in December 2026. As the power station is located in an area covered in pumice , the intake to the power station requires regular maintenance to remove

1518-466: 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

1584-445: 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

1650-462: 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

1716-452: 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

1782-410: 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

1848-657: 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

1914-533: 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,

1980-778: 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

2046-605: 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

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2112-569: 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

2178-506: 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,

2244-400: 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

2310-463: 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

2376-466: The Waikato River. Digging continued, but it soon became obvious that it would be impossible to find any sound rock into which to anchor the abutments of the dam. Mandeno, Lee & Brown quickly redesigned the power station to make use of another site 400 metres further upstream for which they designed a low rock-fill dam from which an open canal, penstocks and a surge chamber could convey the water to

2442-464: 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

2508-595: 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,

2574-700: The board's area. The SHD was in 1958 renamed the New Zealand Electricity Department (NZED). Mandeno identified that Kakahi on the Whakapapa River would be a suitable location. However the SHD turned down the board's application for a licence to build a power station as they also intended to utilize the river to generate electricity in what later became the Tongariro Power Scheme . Continuing his investigations Mandeno identified what he thought

2640-455: The canal's intake gate during an earthquake was improved. A 36-metre-tall by 118-metre-wide by 70-metre-long rock-fill dam impounds the Kuratau River to create Lake Kuratau, which covers approximately 100 hectares and gives a head of 64 metres. The dam is fitted with a spillway on its western side that can pass up to 110 cumecs down the empty bed of the river. From the south eastern end of

2706-403: The completion of the work, the construction site was cleared during the middle of 1962, with all temporary construction buildings removed, after which the site was landscaped with 8,450 trees and 12 acres of new grass. The construction of the power station cost £500,000. In the 1980s the station was shut down while repairs and improvements were made. The canal was earthquake strengthened, fitted

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2772-417: The contract to supply the control panels and install the electrical equipment. Fletcher Steel & Engineering won the contract to supply the steel for the penstocks, intake trash racks, control gates and the powerhouse structure. An 8-km-long access road was created to a construction camp where several workshops, temporary accommodation, and three permanent staff houses were established on a bluff above where

2838-404: 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

2904-505: 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

2970-690: 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

3036-449: The equipment that required. After its construction loan was secured in 1959 tenders were issued for construction and supply of equipment. Fletchers Construction won the contract to undertake the civil works with a price of £295,000. English firm Boving & Co won the contract to supply the turbines and other hydraulic machinery, Swedish firm ASEA won the contract supply the generators, while local company Turnbull & Jones were awarded

3102-399: 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

3168-534: 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,

3234-506: 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

3300-462: The lake a 495-metre-long canal which terminates in a forebay directs the water into two steel penstocks which lead to a surge chamber from which a further two steel penstocks, each 296 metres long convey the water down to a powerhouse located on Kuratau Hydro Rd, Omori. Inside the powerhouse are two 4,000 hp horizontal Boving & Co turbines. Each turbine is directly coupled to a 3 MW, 3 MVA horizontal ASEA three-phase generator. The power station

3366-471: The land was part of a Māori development block that was jointly owned by several Māori families. Both them and the Department of Māori Affairs who were responsible for administering the block were concerned over how much valuable farming land was going to be lost and what compensation would be offered. Eventually, the amount of the compensation that board had to pay to the land owners had to be settled in court. As

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3432-519: 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 ,

3498-731: 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,

3564-633: 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

3630-469: The power house was to be built. The nearest pub was however 26 km away which created issues for those in the workforce wanting to have a drink after work as this was during the days of the Six o'clock swill which meant the pub closed at 6 pm. Construction began in 1959 under the management of Tony Campbell of Fletchers what was intended to be a 27.4-metre-high (90 ft) concrete arch dam which would convey

3696-474: The powerhouse. Once the dam was completed, the lake took one week to fill. By early 1962 one penstock had been installed which allowed its associated generator to be commissioned and then commence commercial operation at midnight on 16 April 1962 and immediately began bringing in a potential revenue of £150 to 200 per day. A large crowd celebrated the official opening of the station on 25 May 1962. The second generator entered service on 21 June 1962. Following

3762-503: The pumice which has become dislodged and then floats down the river to build up behind the dam. Lake Kuratau is popular with a range of recreational users, including duck shooters and fly fishermen. The New Zealand Fly Fishing Association frequently uses the lake in its national competitions. In 2009 the lake was used for the Oceania Fly Fishing Championships. Despite covering 100 hectare the lake which created in what

3828-450: 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,

3894-449: The structure supporting one side of an arch , or masonry used to resist the lateral forces of a vault . The impost or abacus of a column in classical architecture may also serve as an abutment to an arch. The word derives from the verb " abut ", meaning to "touch by means of a mutual border". An abutment may be used to transfer loads from a superstructure to its foundation , to resist or transfer self weight, lateral loads (such as

3960-408: The water via a short tunnel and canal to penstocks and hence down to the power house. However, as excavation began it was found that sides of the narrow gorge in which the dam was being built were unstable, with a large amount of sand being encountered. This was a common issue on the volcanic soils of the central North Island and had been encountered on some of the power stations that had been built on

4026-524: 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

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4092-539: 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,

4158-573: 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

4224-539: Was another suitable site in a narrow gorge that could utilize the Kuratau River . The board authorized him to spend up to £400 on further investigations. Satisfied with Mandeno's conclusions, the board in August 1953 decided to apply for a generation licence and commenced discussions with the SHD to determine if they had any objections and with the Local Government Authorities Loan Board. The Loan Board

4290-413: Was prepared to offer a 40-year loan, while the SHD indicated that it was prepared to buy any surplus power produced by the station. Detailed design of the power station was then undertaken by consulting engineers Mandeno, Lee & Brown (of which Lloyd Mandeno was a principal). Delays then occurred as it took time for the board to secure access to the proposed site to undertake detailed investigations as

4356-559: Was the consulting engineer to the King Country Electric Power Board suggested to the board that they consider building a power station. With demand and its revenues increasing (it increased by 1375% between 1948 and 1958), having its own generation would reduce the amount of power the board would have to purchase from the State Hydro-Electric Department (SHD), while also boosting industrial development in

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