113-612: The Roxburgh Dam is the earliest of the large hydroelectric projects in the lower half of the South Island of New Zealand . It lies across the Clutha River / Mata-Au , some 160 kilometres (99 mi) from Dunedin , some 9 kilometres (5.6 mi) to the north of the town of Roxburgh . The settlement of Lake Roxburgh Village is close to the western edge of the dam. In 1944 the State Hydro Department estimated that even with
226-737: 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
339-463: 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
452-452: A British consortium consisting of civil engineering contractors Richard Costain, electrical manufacturers and contractor English Electric and Insulated Callender Cables to design and build the Roxburgh and other New Zealand power stations. The Ministry of Works had reservations about the lack of a guaranteed completion date, difficulties with divided responsibility if the consortium undertook both
565-544: A combined return rail and transfer bus ticket from Dunedin to the site of the power station was 16 shillings. Where possible equipment was shipped on the Dunedin-Roxburgh Railway Line to Roxburgh and from there transported by road to the power station. For instance the transformers were railed from Port Chalmers to Roxburgh on the 40-ton well-wagons and then taken to the power station site on a Rogers 40-ton tank transporter. The stator sections and shafts followed
678-426: 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
791-462: A delay of between nine and twelve months. Despite studies that had indicated that the conditions were less than optimum Arnold Downer made the decision to go ahead. Using twelve bulldozers sufficient accumulated earth and rocks was moved at a rate of 570 m (750 cu yd) over twelve hours on 1 July 1954 to successfully divert the river into the diversion channel. With the river diverted, cofferdams were constructed upstream and downstream of
904-421: 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
1017-422: A further 225 cottages. Eventually the village grew to 724 houses complete with a 90-bed hostel, a 600-child primary school, a cinema, a social hall, 17 shops, three churches, a fire brigade and ambulance building, four tennis courts, a swimming pool and a piped sewage scheme. In addition there were four single men's camps (two on the east and two on the west bank) containing a total of 1000 huts. These facilities cost
1130-514: A hydro power station on the Clutha River. Initially only three 40 MW generating units were to be installed with the station having an ultimate planned capacity of 320 MW. The Clutha River between Alexandra and Roxburgh runs through a deep gorge which offered a number of locations for a power station. Investigations identified five alternative schemes at the Pleasant Valley site, and one scheme at
1243-809: 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
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#17328485037311356-451: 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
1469-456: A meeting at the Prime Minister's summer cottage on 24 April 1954. At this meeting which was attended by representatives of the consortium, Arnold Downer and Arch McLean from Downers were requested by the government to enter the project as the managing partner with a 25% interest. After spending £4 million the existing contract was cancelled and a schedule of rates contract was agreed upon with
1582-586: 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
1695-545: 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
1808-526: 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
1921-434: A revised bid was received and on that basis a contract with a target estimate of £8,289,148 and a 4% fee of £331,566 was awarded on 25 July 1952. The contract had provision for a bonus of £350,000 for early completion. There was a penalty for late division of the river and a £1000 penalty for each day past July 1955 that the power station was not ready for service. The target completion date was 1 June 1955. By late August 1952
2034-469: A similar route. Because of the line larger tunnels on the Waikaka Branch railway line the turbine runners and generator bottom bearing brackets were transported on this line. From the line's terminus at Waikaka, they were transported by road to the power station using a specialized transporter. The Ministry of Works had identified that it had a shortage of the engineering and drafting staff to undertake
2147-448: 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
2260-455: 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
2373-408: A stage that a firm date of 1 July had been selected to attempt the diversion the flow had increased to 340 m/s (12,000 cu ft/s). Extra bulldozers were allocated to the attempt as the steady increased to 420 m/s (15,000 cu ft/s) and then 510 m/s (18,000 cu ft/s). If the diversion couldn't be completed before the peak winter flows the project would have incurred
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#17328485037312486-414: 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
2599-581: 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
2712-617: A total of NZ£2,241,925. As the Otago Central Electric Power Board's network could not provide sufficient power to the village and the project, the government built a temporary power station containing two 1 MW and one 0.4 MW diesel generators, to supplement the supply. In May 1946 the PWD and the New Zealand Railways Department held a meeting to determine what would be needed to transport materials to
2825-511: A union crane driver who had refused to lower a load being carried by his crane when the siren went for a tea break which the contractors estimated would delay the commencement of lake filling by two months. To connect the new power station to the major load centres, a 52 mi (83.69 km) long new 110 kV wood pole line was first built to Gore . The linemen then commenced constructing an 89 mi (143.23 km) long double-circuit 110 kV overhead transmission line using lattice steel towers to
2938-400: A workforce of 80 men fabricated the plates using automatic submerged arc welders into sections in a purpose built workshop and then installed them in position. All welds were X-rayed during fabrication and radiographed after installation as well as pressure tested except for the concrete encased section at the intake. Stevenson & Cook lost money on the penstock contract, which contributed to
3051-552: 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. Fritz Langbein Fritz Langbein (15 March 1891 – 28 April 1967)
3164-435: 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
3277-448: 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
3390-627: 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
3503-466: 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
Roxburgh Dam - Misplaced Pages Continue
3616-445: 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
3729-462: 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
3842-452: 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
3955-410: 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
4068-657: 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
4181-572: The Coal Creek scheme but after the Geographical Board had been consulted the name Roxburgh was chosen as name of the power station in 1947. The MOW was the government department responsible for designing and constructing the government power station in New Zealand. Though it was still unresolved who would be designing and building the dam and power station Fritz Langbein the engineer in chief of
4294-521: The Halfway Bush substation at Dunedin which was completed in July 1955 at a cost of approximately £500,000. The principal connection, however, was a new 266-mile-long (428 km) 220 kV single-circuit overhead transmission line built using lattice steel towers from Roxburgh to a new substation at Islington on the outskirts of Christchurch. By 1949 the surveys for this line were well under way with by 1951
4407-533: 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,
4520-778: 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
4633-580: The Main South Line to Milton where they transferred to the Roxburgh Branch which conveyed them to Roxburgh and from there transported by road to the power station. Consideration was given to extending the line to the construction site but this wasn't proceeded with due to the difficulty of getting past the east end of the existing Roxburgh suspension bridge. To improve the line's carrying capacity some curve easements were undertaken near Round Hill. As
Roxburgh Dam - Misplaced Pages Continue
4746-605: 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
4859-569: 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
4972-506: 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,
5085-400: 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
5198-463: 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
5311-462: The MOW assumed that his organization would be undertaking the design and would at the least build the diversion channel. Therefore, he put in place plans to build a construction village and in July 1949 had the MOW commence work on the excavation of the diversion channel. This channel would eventually be 2,000 ft (610 m) long, 100 ft (30 m) wide and 70 ft (21 m) deep which required
5424-470: The Ministry of Works had completed the diversion channel and the consortium also took over these workers. Prior to their involvement with the Roxburgh project Hannen, Holland & Cubitts experience had been limited to commercial and residential buildings. Zschokke who had expertise in the construction of hydraulic structures were limited to only providing engineering services while Cubitts personnel filled all
5537-512: The Ministry of Works had completed the two cableways that were to be used to carry concrete to the workface. To manufacture concrete on site the Ministry of Works purchased a Johnson concrete batching plant that had been used by the United States Navy in the reconstruction of Pearl Harbour after the Japanese attack in 1941. This came into operation in early April 1953. Upon completion of Roxburgh
5650-549: The South Island by June 1956, the Minister of Works requested the contractors to concentrate all resources on work that would bring forward lake filling as far as possible. To encourage the workforce, the government offered a bonus of £2 per week plus £1 per day if the lake was filled before 19 August. At midnight on 21 July 1956, lake filling began and the lake level commenced rising at an average of 3 ft (0.91 m) an hour. As
5763-545: The South Island, commissioning of the generating unit 1 immediately commenced under the direction of electrical resident engineer Eric Gordon “Sandy” Sandelin. The urgency meant that present from head office in Wellington were the State Hydro-Electric Department chief engineer M. G. “Bill” Latta and its chief power plant engineer W. A. S. Surridge. Also present was the future station superintendent A. Rose. Once
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#17328485037315876-598: The State Hydro-electric Department. By 1951 the projected project delays were serious enough to draw criticism from the Electrical Supply Authority. By now aware of the projected energy shortfalls and the shortage of government resources to complete six other hydroelectric projects that were underway as well as complete Roxburgh, Goosman's response was to announce on 25 September 1951 that tenders would be called from interested parties to undertake
5989-506: The Tamblyn's Orchard site. Initially Site No. 4 at Pleasant Valley, about 2.4 kilometres (1.5 mi) upstream from Tamblyn's Orchard was favoured. Subsequent detailed design studies however found that Tamblyn's Orchard at Coal Creek where the river exited the Roxburgh Gorge near the town of Roxburgh offered the fullest possible head and thus the most power output, better tailwater conditions,
6102-537: The Tapanui Branch to the Main South Line which provided a connection via the Roxburgh branch line to Roxburgh. At its peak up to 15,000 to 20,000 ft of timber was being transported by rail on a daily basis. At the Roxburgh railway station the PWD erected silos to store the expected 50,000 tons of cement a year that would be consumed at the project's peak as well as a six-pole 60 ton (61 tonne) lifting gantry It
6215-464: 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
6328-477: The advantage of being less remote, requiring less geological investigation, half the materials for the same power output and a better climate in which to undertake construction work, which were important considerations at a time of serious shortages of labour and cement. Historical records showed that the long term flow of the river was 500 m/s (17,650 cu ft/s) and that a controlled flow of 420 m/s (15,000 cu ft/s) would be possible through
6441-595: 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,
6554-405: The batching plant which was fully occupied supplying concrete for the dam blocks. In July 1954 Downer replaced 20 senior contractor staff that he had inherited with people of this choosing, many from Morrison–Knudsen Co. A significant appointment was that of A. I. Smithies, a very experienced hydro construction engineer from Morrison-Knudsen as construction superintendent. With management in place
6667-540: The best access and would be closest to suitable locations for both construction and permanent villages. In March 1949 the government committed to building at Tamblyn's Orchard and plans were prepared to enable work on the diversion channel to start in June 1949. In October 1949 at the request of the Ministry of Works, Dr. John L. Savage - a former Chief Design Engineer of the United States Bureau of Reclamation - visited
6780-437: The blocks had reached its final stable temperature the slots were filled with concrete. Once the concrete in a block was stable the coils were filled with grout. A 20 ft (6.1 m) deep low pressure consolidation grout curtain was installed on the upstream side of the dame and extending into both abutments to improve the strength of the rock under the dam and prevent leaks. Drainage holes were constructed just downstream of
6893-470: The civil aspects of the project. This required the rapid production of tender documents and specifications by a short staffed government design staff. Bidders had the choice of offering on either a bill of quantities basis or by nominating a 'target estimate' plus a 4% fee. In this type of contract the Government met all costs and the contractor received a fee of 4% of the total cost up to the target estimate. If
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#17328485037317006-622: The company being wound up in 1959. Fletcher Construction undertook the work to clad and roof the power house. The State Hydro-electric Department undertook the design, purchase and installation and commissioning of the electrical equipment. Tenders for supply of the major electrical plant were issued in October 1949 with contracts awarded in May 1950 at a cost of £1,000,000 for the first four generating units. The State Hydro Department established itself on site in June 1953. Access to undertake their activities
7119-478: The construction camps established and the material on order. By 1954 the first section of the line had been completed, which allowed it to carry power from Tekapo A to Christchurch. A second section as far south as the Waitaki Valley helped improve supply conditions during winter. The Roxburgh-Islington line cost approximately £1,000,000 and was completed by the winter of 1956. With power cuts being applied across
7232-514: The construction of earthen dams and its only engineers with the necessary experience were engaged on the Cobb Power Station. Many of the design decisions were based upon results from studies undertaken from 1949 to 1954 on a 1:80 scale model of the dam at the Department of Scientific and Industrial Research 's Hydraulics Laboratory at Gracefield, Lower Hutt. Initially the project was known as
7345-466: The cost varied from the estimate, then 25% of the change was added to or subtracted from the fee. A 'no loss clause' meant that if the cost overruns where high enough the contractor could lose their entire fee but would not suffer any further loss, other than those for not meeting agree completion dates. Eight tenders were received. Three were fixed price with a bill of quantities and the remainder were target estimates. The Ministry of Works had estimated that
7458-408: The crest of the spillway while the contractors began drilling and inserting more grout. Meanwhile at 12:30 pm on 23 July a speedboat driven by Ken Harliwich and accompanied by Willis Wetherall to leave Roxburgh for Alexandria making the first boat trip on the new lake. By 11:20 am on 23 July 1956, the lake had filled to the crest of the spillway water. With a desperate shortage of electricity affecting
7571-404: 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
7684-462: The dam and the water pumped out between them. The upstream cofferdam consumed 180,000 m (240,000 cu yd) of material, while the downstream cofferdam consumed 54,000 m (71,000 cu yd) of material. There were expectations that gold would be found in the exposed river bed, but despite the MOW taking out a mining licence and employing two experienced gold miners, the results were disappointing. Once free of water work commenced on
7797-505: 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
7910-477: The design and construction, the potential for the cost to be higher than if competitive tenders were called and that it could give the consortium a monopoly over future projects of a similar nature. The State Hydro-Electric Department didn't want to be restricted to one electrical equipment manufacturer and also saw the offer as a threat to their transmission line construction staff. Taking these concerns into account and wishing to avoid using up precious overseas funds
8023-690: 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
8136-436: The engineers were satisfied that the machine was fit for service, it was connected at 6 pm to the national grid. Due to the reduced head, the machine's output was limited to 30 MW. By the end of the next day generating unit 2 had completed commissioning and was also connected to the system. This allowed the 220 kV line to Islington to be brought into service as two machines were needed to provide sufficient reactive power to charge
8249-432: The excavation of the foundations for the main block of the dam. A large gravel filled hole was discovered in the centre channel or "gullet" of the river bed. This gullet which was 50 ft (15 m) deep and varied in width from 50 ft to 30 m (100 ft) was dug out and filled with a mix of pozzolana (fly ash) and cement under the dam while under the powerhouse Prepakt concrete was used as this reduced demand on
8362-399: 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
8475-475: The flows from the remaining lakes. After investigation found that the soil conditions were unsuitable at Lake Wanaka only Lake Hāwea received new control structure. This was commissioned in 1958 and consists of four radial gates housed in an earth dam. The dam raised the existing lake level and currently provides approximately 290 GWh of storage. In December 1947 the Labour Government approved plans to build
8588-534: 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,
8701-438: The government's expense the consortium flew out 309 workers from Great Britain. By October 1953 it was clear that the consortium would not meet the contracted July 1955 date for generation of the first power. In an attempt to improve progress the contractor replaced a number of senior project staff. Labour relations were also deteriorating due to uncertainty over the management changes, reduction in working hours to 40 per week and
8814-511: The grout curtain as well as under the power house with 40 pressure gauges installed to record the up pressure on the structure. A total of 700,000 cu yd (540,000 m) of concrete were used in the construction of the dam and spillway consuming 600,000 cu yd (460,000 m). Cement was mostly sourced from the Milburn Lime and Cement Company's factory at Burnside (near Dunedin) or via ship into Port Chalmers. A major expansion
8927-506: 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
9040-456: The impact of cost overruns on the workers pay. In November 200 British workers demanded either a 70-hour working week or their tickets back to Great Britain. With it having been necessary in 1953 to introduce power rationing in the South Island due to a shortage of generation the government decided the slow progress couldn't continue and requested two directors of Downer & Co , a major New Zealand construction company to attend in two days time
9153-461: The junction at McNab and then via the Waikaka branch line to its terminus at Waikaka. From there they were transported by road to the power station using a specialized transporter. This assist in the transfer from rail to road transport a 4-pole 30 ton (30.5 tonne) gantry was erected at the Waikaka railway station. The road between Roxburgh and the construction site was upgraded and a second bridge built on
9266-414: The lake began to fill, increasing levels of water began to flow from the drainage channels behind the grout curtain in the right abutment, which indicated that the grout curtain was faulty. Investigations concluded that further grouting would have to be performed (which took about a fortnight) before the lake could be raised to its final level. The decision was made to allow the lake to fill to no further than
9379-527: The large amount of power station construction that the government had committed to in the North and South islands. Fritz Langbein believed that provided 1,000 workers could be obtained from overseas then the MOW would be able to complete the entire project in-house by 1954. In May 1949 the government reluctantly accepted that overseas contractors may have to be employed to meet the planned construction programme. This admission lead to an unsolicited bid being received from
9492-519: 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 ,
9605-731: 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,
9718-577: The line while it was being undertaken. As an alternative an investigation was undertaken into lengthening the Tapanui Branch line from its terminus at Edievale though a tunnel and some clay cuttings in the Dunrobin Hills to the Clutha River where it could connect with the Roxburgh branch line. Eventually it was decided to wherever possible use the Roxburgh branch line for all construction materials and smaller items of equipment. These were transported on
9831-418: The load carrying capacity of the existing roads was constrained by bridges at Henley (on State Highway 1) and Beaumont on State Highway 8) it was decided that as the Waikaka Branch railway line had no constricting tunnels it would be used to transport out of gauge heavy items such as the turbine runners and bottom bearing brackets. These items were transported on the Main South Line from the port at Bluff to
9944-542: The long length of line. The third generating unit was commissioned on 18 August 1956 and the fourth unit on 11 December 1956. The power station was officially opened on 3 November 1956 by Stanley Goosman in the presence of 600 invited guests, plus members of the public. Delivery of the four remaining generating units began late in 1959, with unit 5 being commissioned on 19 April 1961, unit 6 on 18 August 1961, unit 7 on 13 March 1962 and unit 8 on 1 June 1962. Hydroelectricity Hydroelectricity , or hydroelectric power ,
10057-475: The management roles. By March 1953 the Ministry of Works became concerned at the progress being made by the consortium and that their management team lacked the experience to construct a hydro power station, which was highlighted by the large amount of rework being undertaken. Progress was not helped by the Government directing the employment of a large number of assisted immigrants many of whom had little construction experience and limited English. In early 1953 at
10170-594: The offer was formally rejected in September 1949 by the Minister of Finance in the Labour government. Meanwhile, work continued on site on completing the construction village and creating the diversion channel. However progress was slow, with completion of the diversion not expected until 1953 instead of the planned 1951. In 1949 the newly elected national government, which ideologically favoured private enterprise, appointed Stan Goosman as both Minister of Works and Minister of
10283-449: The other profile had a flatter slope and were only wide enough at the top to house the road across the top of the dam. In conjunction with the block sizes, different concrete mixes and the passing of cold water through cooling coils were used to maintain the block temperature at 10˚C (50˚F) and thus cracking of the concrete. Cracking can allow water into the body of the dam which can lead to allow uplift and instability during earthquakes. Once
10396-546: The over the Teviot River on the eastern side of the Clutha River to supplement the existing bridge. At the construction site a 220 ft (67 m) long single-lane Bailey bridge with a carrying capacity of 24 tons (24.4 tonnes) was installed in 1949 to provide access across the river. Timber used in the construction of the power station and the village was sourced from the Conical Hills Mill at Tapauni and taken via
10509-633: 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
10622-452: The plant was transported first to Benmore power station and then later to Aviemore power station and the Pukaki dam to mix aggregate for the penstocks, spillways and other concrete structures. The consortium bought from overseas 82 engineers, supervisors and administration staff and 322 workmen to the project and took over the civil aspects from the Ministry of Works on 29 Sept 1952. By this stage
10735-471: The power station. The designers estimated that with an overall efficiency of 85% the mean output would be 160 MW and assuming an annual power factor of 50% the station could deliver a maximum output of 320 MW. The Clutha River is fed from Lake Hāwea , Lake Wakatipu , and Lake Wānaka . There were already existing control gates on the Kawarau River at the outlet of Lake Wakatipu and it was decided to control
10848-552: The power stations currently under construction they would only be able to meet projected South Island load up until 1950 or 1951 and that a new large power station was required. Detailed investigations by the Public Works Department identified two alternatives, Black Jack's Point on the Waitaki River (where eventually Benmore Power Station would be built) and Roxburgh Gorge on the Clutha River. A power station at Roxburgh had
10961-403: The project was meeting its target dates with work on the powerhouse six months ahead of schedule. The dam was constructed in 50 ft (15 m) wide concrete blocks with 5 ft (1.5 m) wide slots between them constructed in two profiles, those associated with the penstocks had an additional section containing intakes and screens as well as a downstream slope to support the penstock while
11074-839: The proposed site of the power station. The main loads associated with the first four generating units were as follows: thirteen generator transformers, each 39.5 tons (40.1 tonnes), 15 ft 6 in (4.72 m) long, 10 ft 4 in (3.15 m) high, 8 ft 2 in (2.49 m) wide; twenty-four stator sections; each about 19 tons (19.3 tonnes) gross, 14 ft 9 in (4.5 m) by 9 ft 1 in (2.77 m) by 6 ft (1.83 m); four shafts and thrust plates, each 33½ tons (34 tonnes) gross, 20 ft (6.1 m) long by 6 ft 6in (1.98 m) by 7 ft 10 in (2.39 m); four turbine runners, each 25 tons (25.4 tonnes), 12 ft 10 in (3.91 m) diameter, 6 ft 7 in ( 2 m) high; four generator bottom bearing brackets, each 20 tons (20.3 tonne) gross, 12 ft (3.66 m) by 12 ft by 6 ft 1 in (1.85 m). The most direct rail route
11187-450: 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,
11300-413: The removal of 255,000 cu yd (195,000 m) of material. By the end of 1950 720 workers were being employed on site. To house the workforce the Ministry of Works first built in 1947 a single men's camp and cookhouse on the west bank of the river. In 1950 work began on erecting 100 workers' cottages. The following year began on building a YMCA hall, shops, a hospital and nurses accommodation and
11413-493: The renamed Cubitts Zschokke Downer with a planned completion date of late 1956. As a result of the forming of this new consortium Arnold Downer was put in charge of all site activities. The preliminary works for the diversion of the river got off to a bad start when the explosive charge used in mid-June to remove the upstream dumpling damaged the steel sheet pile cofferdam downstream of it. This cofferdam has been constructed to ensure that water didn't carrying any blast debris from
11526-456: The site and provided advice on the proposed design options. While an earth dam was more suitable at the wider Pleasant Valley location after considering various options it was decided in October 1950 that due to the geology at Tamblyn's Orchard a solid-concrete gravity dam would be more appropriate. Another consideration was that the Ministry of Works and Development (MOW) had limited experience with
11639-434: The upper dumpling into the sluice channel. Eventually the debris and the cofferdam were removed, allowing unrestricted flow down the diversion channel. Now it was necessary to block off the river so all of the water flowed down the diversion channel. The river's average flow was 500 m/s (17,650 cu ft/s) and by June it had fallen to 170 m/s (6,000 cu ft/s), but by the time work had been completed to
11752-405: The work would cost £10,198,000 and the average for seven of the bidders was £10,068,838. The lowest bid was £7,4412,419 from Holland, Hannen & Cubitts of England. The government engaged Sir Alexander Gibb & Partners of London to assess the ability of the bidders to undertake the work. After negotiations with Hannen, Holland & Cubitts of England who were joined by S A Conrad Zschokke
11865-403: The workfare was able to be reduced from the 1,107 when Downers took over, to 850. Under Downer's management the pace of construction increased with the weekly concrete pour rapidly improving. In the first week of October 1954 5,400 cu yd (4,100 m) of concrete was poured, which had increased to 6,700 cu yd (5,100 m) poured over the course of the next week. By May 1955
11978-524: 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
12091-539: 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,
12204-605: Was a New Zealand civil engineer , engineering administrator and company director. Langbein was born on 15 March 1891 in Nelson , the son of Frederick John Langbein, a commercial traveller and farmer, and his wife, Mary Ross. He was educated at Nelson College from 1904 to 1908. During World War I , Langbein served with the New Zealand Tunnelling Company of the New Zealand Expeditionary Force on
12317-573: 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
12430-506: Was expected that Shipments of bulk cement began in mid 1953 and by July of that year 600 to 1,100 tons were being shipped per week. By July 1955 demand had dropped to 800 tons per week with shipping of cement finishing in November 1956. By April 1956 Milburn had supplied 105,000 tons of cement with another 10,000 tons still to be delivered to complete the project. NZR operated occasional sightseeing trains from Dunedin and Christchurch. The cost of
12543-619: Was first provided in August 1954 and erection of the first generating unit began with the first scroll case concreted in by March 1955. In November the joints in the stator windings of the generators were discovered to be faulty. Fortunately sufficient time became available to re-make all the joints when from 24 November 1955 for 23 work days up until the Christmas break the members of the New Zealand Workers Union were on strike in support of
12656-487: Was undertaken by Milburn in order to supply the cement. Aggregate was obtained from the Clutha River at Commissioner's Flat, while water came from the river. Fletcher Holdings subsidiary, Stevenson & Cook manufactured and installed the penstocks, the steel frame of the powerhouse and the spillway gate winches The rolled plates for the penstocks were transported by truck from their factory in Port Chalmers to site where
12769-506: Was via the Roxburgh Branch line to its terminus at Roxburgh. However this line had an uncompensated 1 in 41 grades and five chain (100.6 metre) curves that would limit the loads to 180 tons per engine. As well, four tunnels including those at Manuka and Round Hill on the line restricted the physical size of what could be transported, leading to consideration being given to enlarging them. This would have been expensive and restricted use of
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