73-725: The Aniwhenua power station is a hydroelectric power facility in Bay of Plenty in New Zealand located on the Rangitaiki River upstream of the Matahina Power Station . Water is drawn from behind a dam above the Aniwhenua Falls and diverted through a canal and a headpond to the power station before being discharged back into the river. The power station is named after the falls which are adjacent to
146-745: 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
219-463: 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
292-521: A Prudent Discount Agreement exists for Aniwhenua that makes it part of the Edgecumbe GXP. Aniwhenua is operated to maximise injection into the Horizon network. If there is any generation in excess of local load, this is exported to the national grid. As a result, the power station is effectively embedded. Operation of the power station is covered by the requirements of five resource consents, with
365-468: A campground on the northeastern lakeside, near the dam. A series of feasibility studies and investigations into establishing a hydroelectric scheme upstream from the Matahina Dam were performed throughout the 1970s. Construction on the scheme occurred between 1977 and 1981, and included the creation of a 10 m dam, which would hold back the newly formed Lake Āniwaniwa. The original name of the lake
438-426: 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
511-421: 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
584-809: 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
657-451: 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
730-687: A local hydro scheme in mid-1973. Preparation of a feasibility report was authorised in December 1973, with the report being completed in September 1974. The study determined that a power station on the Rangitaiki River at its confluence with the Pokairoa Stream, midway between Murupara and Whakatane. The scheme was technically feasible and financially viable. The main identified environmental impacts were significantly reduced flows over
803-592: 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
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#1732787360285876-548: 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
949-540: 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
1022-861: A serious leak developed in the dam during Nova's ownership. Following investigations and development of a solution by consultants Tonkin + Taylor, the contracting firm of Waiotahi Contractors commenced in February 2006 the 58 day repair of the leak which took 58 day at a cost NZ$ 2.78 million. Looking to raise capital to invest in other energy projects in the North Island Nova agreed to sell Aniwhenua in November 2015 to Southern Generation Partnership (a partnership between Pioneer Generation Investments and Roaring Forties) for approximately NZ$ 100 million with ownership transferring in April 2016. The Roaring Forties
1095-448: 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
1168-455: 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
1241-414: 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
1314-581: 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
1387-505: 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. Lake Aniwhenua Lake Āniwaniwa (unofficially known as Lake Aniwhenua )
1460-435: 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
1533-452: 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
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#17327873602851606-555: Is a partnership between The Power Company and Electricity Invercargill. At the beginning of December 2018 Pioneer Energy took over the services agreement with the Southern Generation Partnership to operate and maintain the power station. A 200-metre-long, 10-metre-high dam located upstream of the eight-metre-high Aniwhenua Falls impounds the Rangitaiki River and Pokairoa Stream at their confluence at Black Road, Galatea, approximately 65 km upstream from
1679-569: Is a small man-made lake on the Rangitaiki River , in the Bay of Plenty region of New Zealand . The lake is situated 13 km north of the town of Murupara , and about 16 km upstream of the Matahina Dam. The lake was created as a result of the construction of a 10 m high dam, part of the Aniwhenua hydroelectric scheme . Lake Āniwaniwa is a long, shallow lake that measures 4.5 km long and 0.5 km across, with total area of about 2.1 km . The Whakatane District Council manages
1752-635: 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
1825-476: Is driven by the compensation flow and supplies power to the local distribution network via Horizon Energy's Galatea feeder. Compensation water is also released from the headpond through a draw off pipe into the original course of the Pahekeheke Stream. Via two 11/33/110 kV tertiary wound step-up transformers Aniwhenua is the primary supplier of electricity to Horizon Network's distribution network in
1898-470: 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
1971-435: Is home to various species of native waterbirds, including the New Zealand shoveler , New Zealand scaup and Australian coot . Surveys conducted at the lake in the 1980s (around four years after the completion of the dam) also indicated the presence of other species such as the marsh crake , spotless crake , New Zealand dabchick and the threatened Australasian bittern . Both trout fishing and game bird hunting (during
2044-445: 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
2117-462: 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
2190-452: 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
2263-410: 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
Aniwhenua Power Station - Misplaced Pages Continue
2336-679: 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
2409-575: The Department of Conservation and the Electricity Corporation of New Zealand . In 1995, the number of elvers being translocated annually to Lake Āniwaniwa reached 149,000. Some locals have taken it upon themselves to manually transfer elvers and mature eels to and from Lake Āniwaniwa. Lake Āniwaniwa additionally contains both rainbow and brown trout , as well as mosquitofish , common bully and goldfish . Lake Āniwaniwa
2482-549: 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,
2555-806: 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
2628-633: 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
2701-583: 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
2774-506: 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,
2847-400: 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
2920-475: The Aniwhenua Falls, inundation of productive farm land and the displacement of one family, as well as the long term accumulation of sediment in the lake that the project would create. The issue of the reduced flow was managed by the imposing of a minimum residual flow over the falls. The estimated cost was NZ$ 12.5 million. Following the obtaining of water rights, government consent and other necessary approval, construction and equipment supply contracts were let in
2993-744: The Bay of Plenty Electricity Limited. Bay of Plenty Electricity subsequently became the first electricity company to be listed on the New Zealand stock exchange. In July 1998 the New Zealand Government passed the Electricity Industry Reform Act which was intended to change the structure of the electricity industry to encourage competition. This Act required the operational separation of distribution and generation business activities by 1 July 1999 and separation of
Aniwhenua Power Station - Misplaced Pages Continue
3066-599: The Galatea and Kaingaroa regions via a single 33 kV feeder that runs to Snake Hill and then splits into two feeders to supply Galatea with a further single feeder from Galatea to Kaingaroa. Any surplus above this local demand is exported via a 110 kV circuit to the Matahina Power Station where the two power stations combine to export electricity to the national grid via two 110 kV circuits to Transpower 's Edgecumbe Substation. For transmission pricing purposes
3139-463: 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
3212-602: The Matahina dam downstream, have impeded this migratory pathway. Since the creation of the dam, numerous studies exploring strategies to mitigate the impact of the Lake Āniwaniwa dam on the migration of Rangitaiki have been conducted, often supported by the operators of the Aniwhenua hydroelectric scheme. The Department of Internal Affairs initiated a programme in 1983 to manually translocate elvers upstream, work later continued by
3285-464: 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
3358-595: 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,
3431-404: 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
3504-485: The dam a 2.2 km long concrete-lined canal conveys water to the Pahekeheke Headpond, which was created by damming the Pahekeheke Stream. From the headpond two penstocks transport the water down to a powerhouse containing two Escher Wyss vertical Francis turbines which are each directly coupled to an ASEA 11 kV 12.5 MW synchronous generator. The station produces on average 127 GWh per annum. The output from
3577-505: 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
3650-505: The daytime peaks. and The power station typically generates at least 8 MW, as below this value it will be necessary to spill water which will impact on the river downstream. There is an ongoing programme to transfer migrating elvers and eels both upstream and downstream from the lake, to maintain eel stocks. The headwaters of the Rangitaki River collect lightweight pumice sands and partly greywacke gravels which are deposited in
3723-705: 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
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#17327873602853796-399: 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
3869-534: 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,
3942-399: The generating units is discharged back to the river just below the falls. The generator size was based on the desire to meet the power board's load factor of 65%. The power station has a head of 38 metres. Compensation water of a 2.5 cumecs is also released from the dam to preserve the original river channel and maintain flow over the falls. A small turbine coupled to a 100 kW generator
4015-506: 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
4088-573: The investigation and design work, cheap loans to finance construction as well as loans from the NZED to cover operating losses in the early years of approved schemes. The government established the Committee on Local Authority Hydro Development (CLAHD) to evaluate applications for grants or loans from supply authorities. Taking up this opportunity the Bay of Plenty Electric Power Board which had begun operations in 1928 and engaged consultants to investigate
4161-515: The lake. During its first 15 years of operation the lake accumulated approximately 1.5 million m3 of sediment. Loss of storage has been managed by constructing training banks to encourage the sediment to settle in the deeper areas of the lake as well as lowering of the lake and flushing during floods. In addition, it has been necessary to undertake limited dredging operations to remove sedimentation with 30,000 m3 removed in 2002. Hydroelectric power Hydroelectricity , or hydroelectric power ,
4234-519: 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 ,
4307-750: 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,
4380-466: The ownership by 1 January 2004. As a result, in 1998 Bay of Plenty Electricity sold its retail and generation business, together with its name to Nova Energy, which was owned by the Todd Corporation . On 1 April 1999, the remaining distribution assets were transferred to a new company, Horizon Energy Distribution Limited (which operates these assets under the name of Horizon Networks). After
4453-633: 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
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#17327873602854526-516: The power board in the black. The Energy Companies Act was enacted in 1992, and amended later that year. This act required the corporatisation of the electricity and gas undertakings of electric power boards and municipalities with the aim of ensuring a commercial and efficient approach to electricity distribution and supply. As a result, the power board was forced in August 1994 to vest all of its assets including Aniwhenua and associated water rights to
4599-458: The power station. In the late 19th century and early 20th century, numerous small local power generation stations were built by both private and local authorities. From the 1920s onward as the state electricity system expanded and the national grid was developed, development of small local power stations declined as the centralisation of electricity supply under state control increased. The 1973–74 oil shock, nation-wide electricity shortages during
4672-482: The principal consent expiring in September 2026. The lake level operates between a normal operating range of 146.1 to 146.8 metre RL (relative to the Moturiki datum) with the emergency spillway having a level of 148.6 metre RL. The power station operates as a run of river scheme as the lake is small in terms of river flow. Low overnight demand allows refilling of the lake and drawdown to provide increased generation over
4745-450: 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,
4818-608: The river mouth to create Lake Aniwhenua . Smaller dams also divert water from the Pokairoa into Lake Aniwhenua. The lake is 4.5 km long by approximately 500 m wide and is 255 ha in area. The maximum depth of the lake is 10 metres at the dam but it is typically less than three metres deep in other locations. The dam contains two wheeled penstock intake closure gates, two radial spillway gates which can discharge 1,270 cumecs of water. As well there are three additional flap type flood gates designed to handle higher flood conditions. From
4891-406: The second half of 1977. The civil works which commenced by the end of 1977 constructed by Downer and Company which involved the excavation of one million tons of material and the placing of 270,000 cubic metres of fill, 20,000 cubic metres of concrete and 884 tonnes of reinforcing steel. Aniwhenua began generating on 3 October 1980. The 1982 annual report for the board showed that the total cost of
4964-430: The station to 31 March 1982 was $ 27,767,203 of which $ 24,628,809 was financed by government loan. The book value of the scheme as at 31 March 1992 was $ 21,109,000. By the 1985/86 financial year, the scheme was breaking even financially and was able to trade its way into long-run profit without any write-offs of debt. Over the period from 1989 to 1992 as its trading activities were making a loss the profits from Aniwhenua kept
5037-420: The winters of 1973 and 1974, a renewed policy emphasis on regional development by central government, and increased uncertainty as to future wholesale electricity price trends lead to the New Zealand government to re-evaluate its policy regarding local hydro development. As a result, in 1977 the government announced that they would subsidize local power station schemes of less than 50 MW by providing grants to cover
5110-524: 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
5183-539: 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,
5256-486: Was Lake Aniwhenua, which was erroneously taken from the name of the nearby Āniwaniwa falls. Under the Ngāti Manawa Claims Settlement Act 2012 , Lake Āniwaniwa became the official name of the lake. Mature longfin and shortfin eels both migrate down the Rangitaiki River each autumn, following their upstream migration as elvers (juveniles). The construction of the dam at Lake Āniwaniwa, along with
5329-586: 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
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