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65-807: The Douglas Dam was built by the Tennessee Valley Authority at a record pace from February 2, 1942, through February 19, 1943, to provide hydroelectric power and to control flooding downstream in the Tennessee River Valley . Douglas Dam is located just over 32 miles (51 km) upstream from the French Broad River's confluence with the Holston River in Knoxville , to form the Tennessee River . The Douglas Lake reservoir inundates about

130-592: A 40-mile (64 km) stretch of the French Broad River between the Douglas Dam and the Irish Bottoms area near Newport . Small portions of the Nolichucky and Pigeon rivers are also impounded by the lake. During the winter months, the Tennessee Valley Authority lowers the water level to help control flooding, meet power demands, and many other objectives. This is important to know in advance to make plans to stay near

195-737: 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

260-463: 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

325-561: A world record for a project of its size. Its first electric generator went on-line on March 21, 1943, and its second one went on-line on January 1, 1944. Its powerhouse operated at maximum capacity for most of its first year of operation. After its completion, the Douglas Dam powerhouse furnished electric power for two critical war industries, aluminum production and the Manhattan Project 's uranium enrichment operations at nearby Oak Ridge, Tennessee . The Douglas Dam powerhouse

390-576: A dam on the French Broad River in East Tennessee . After the Japanese attack on Pearl Harbor resulted in the United States entering World War II, construction of this dam became a high priority in order to generate hydroelectric power for national defense purposes. Large amounts of electricity were needed to produce aluminum and magnesium – vital metals for wartime warplane -manufacturing. When

455-421: 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

520-494: 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 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

585-809: 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

650-451: 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

715-586: 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

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780-545: 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

845-470: 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

910-448: 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

975-455: 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

1040-414: 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

1105-602: A total capacity of roughly 1,461,000 acre⋅ft (1,802,000 dam ) of water, of which 1,081,880 acre-feet (1,334,480 dam ) is reserved for flood control. The water stored in Douglas Lake serves an important purpose during extended dry periods and droughts in East Tennessee and western North Carolina. Then, water is released from this and other dams on the upper tributaries of the Tennessee River in order to maintain an eight-foot-deep navigation channel for barges on

1170-581: 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

1235-448: 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

1300-522: Is a stub . You can help Misplaced Pages by expanding it . Douglas Dam Douglas Dam is a hydroelectric dam on the French Broad River in Sevier County, Tennessee , in the southeastern United States. The dam is operated by the Tennessee Valley Authority (TVA), which built the dam in record time in the early 1940s to meet emergency energy demands at the height of World War II . Douglas Dam

1365-418: Is a common time for these releases, exposing the lake bottom up to several hundred feet from the shoreline and resulting in suspension of power generation when the lake reaches dead pool levels. This also helps to mitigate potential flood and overtopping conditions that could result from spring rains and meltwater from surrounding mountain streams. Another secondary purpose of the Douglas Dam and Douglas Lake

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1430-480: Is a hydroelectric power producer with four large water turbines that drive four large electric generators . Their combined peak electric power -production capacity is 146,000 kilowatts . In addition to hydroelectric generation, there are several secondary purposes of the Douglas dam and reservoir. One of these is flood control for the French Broad River and also for the Tennessee River downstream. Douglas Lake has

1495-710: Is a recreational destination for up to two million visitors per year. Primary uses of the lake and its shores are fishing, boating, water skiing, swimming, camping, hiking, and wildlife observing. In addition to a number of private campgrounds in this area, TVA provides the Douglas Dam Headwater Campground and the Douglas Dam Tailwater Campground for public use. The Tennessee Wildlife Resources Agency stocks Douglas Lake with tens of thousands of sauger and crappie fish each year to thrive and then provide recreational and food fishing. One of

1560-589: Is a straight reinforced concrete gravity-type dam 1705 feet (520 m) long and 202 feet (62 m) high, impounding the 28,420-acre (11,500 ha) Douglas Lake . The dam was named for Douglas Bluff, a cliff overlooking the dam site prior to construction. The French Broad River winds its way westward from the Appalachian Mountains , gaining considerable strength after absorbing the Pigeon River and Nolichucky River near Newport before eventually joining with

1625-627: 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

1690-400: Is available by Tennessee State Route 338 which crosses the river just downstream of the dam. Interstate 40 (Exit 407) passes a few miles to the north. The dam is also accessed from I-40 exit 412 via Deep Springs Road and Tennessee State Route 139 . The dam does not have any navigational locks . During 1941, President Franklin D. Roosevelt requested Congress to allocate funding for

1755-435: Is for recreational boating , swimming, and fishing . Significant amounts of freshwater fish are caught in Douglas Lake as part of the food supply for human beings. Douglas Lake has an average of 500 miles (800 km) of shoreline, and it has an average surface area of nearly 30,000 acres (120 square kilometers), with both measurements varying according to the seasonally changing water level of Douglas Lake. Douglas Lake

1820-466: 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

1885-445: 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

1950-471: 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 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

2015-462: 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

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2080-452: 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

2145-410: 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

2210-657: 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

2275-647: The Holston River at Knoxville to form the Tennessee River . Douglas Dam is located 32 miles (51 km) above the mouth of the French Broad. The area is a geological border between the Foothills of the Great Smoky Mountains (which rise to the south) and the Appalachian Ridge-and-Valley range . The reservoir includes parts of Sevier, Jefferson , Hamblen , and Cocke counties. Road access

2340-778: 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

2405-537: 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

2470-569: 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

2535-484: The inland waterway of the river from Knoxville down to its mouth at the Ohio River . If it were not for these releases of water, parts of the Tennessee River would become unnavigable. Furthermore, the water that is released is then available for all the drinking-water supplies of cities and towns downstream, and in addition, it is available for watering farms during the droughts. Intentional drawdown during winter months

2600-506: 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,

2665-463: The IEA released a main-case forecast of 141 GW generated by hydropower over 2022–2027, which is slightly lower than deployment achieved from 2017–2022. Because environmental permitting and construction times are long, they estimate hydropower potential will remain limited, with only an additional 40 GW deemed possible in the accelerated case. In 2021 the IEA said that major modernisation refurbishments are required. Most hydroelectric power comes from

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2730-565: The TVA first asked Congress for the funds to construct Douglas Dam in late 1941, U.S. Senator Kenneth McKellar (D-Tennessee) opposed the project because it would flood some 40 square miles (100 km ) of fertile farmland important to the local food canning industry. McKellar succeeded in blocking this project for two months, but his opposition was overridden because of national defense needs. The Office of Production Management predicted that wartime industrial production would peak in 1943, and that

2795-464: 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

2860-595: 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,

2925-548: The construction of the dam were hauled to the site by the Smoky Mountain Railroad , which had constructed a spur line to the site from nearby Sevierville . Profits from supporting the dam construction saved this railroad from bankruptcy. The Douglas Project required the construction of ten smaller, earthen saddle dams to fill in gaps along the adjacent ridgeline and permit a higher water elevation than would otherwise be possible. Most of these saddle dams are located in

2990-404: 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

3055-505: 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

3120-690: 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

3185-399: 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

3250-456: The generating capacity of existing and planned TVA projects would be short by 230,000 kilowatts of electric power . Congress approved the project in January 1942 and President Roosevelt signed the bill into law on January 30, 1942. Construction began immediately on February 2 as a rush project, and it used blueprints , civil engineers , construction workers , and construction machinery from

3315-458: The hills southeast of the main dam. One protects downtown Dandridge, Tennessee , which along with the communities of Shady Grove, Oak Grove, and Rankin, was originally scheduled to be flooded by the reservoir behind the dam. However, the citizens of Dandridge appealed to the First Lady , Eleanor Roosevelt , noting that this town was the only place in the United States named for Martha Washington ,

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3380-527: The lake. The resort town of Baneberry is located on the northern shores of the lake in Jefferson County . Dandridge , the county seat of Jefferson County, is located mostly on the northern shores with a small portion on the southern. Parts of downtown Dandridge are located below the lake's operating levels, and are protected by an earthen dam. This article related to a protected area in Tennessee

3445-492: The largest amount for the region since 1990. Meanwhile, globally, hydropower generation increased by 70 TWh (up 2%) in 2022 and remains 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

3510-731: 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,

3575-609: The late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand arising from 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,

3640-488: 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 , 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

3705-651: 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, 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,

3770-431: The nearby Cherokee Dam , which had been completed a few weeks earlier in late 1941. The construction of the Douglas Dam and its accompanying reservoir required the purchase of 33,160 acres (13,420 ha) of land, 5,182 acres (2,097 ha) of which were forested and had to be cleared. This project also required the relocation of 525 families and 32 cemeteries, and the rerouting of several miles of roads. Supplies for

3835-633: 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

3900-413: The problems of hydroelectric dams is the periodic reduction of dissolved oxygen in the tailwaters downstream of the dam. Three systems are used at Douglas Dam to improve oxygenation. Hydroelectric power Hydroelectricity , or hydroelectric power , is electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity , almost 4,210 TWh in 2023, which

3965-450: 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,

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4030-427: The wife of the first president George Washington . Mrs. Roosevelt ensured that a saddle dam was built to protect Dandridge from flooding. The saddle dam was built of earthen fill, and reinforced on its lakeside by gravel and riprap . In spite of a four-week work delay caused by flooding, the Douglas Dam was completed and its floodgates were closed on February 19, 1943, 382 days after the construction began; this set

4095-524: 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

4160-539: 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,

4225-573: 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

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