Hydroelectricity is electricity produced from hydropower. In 2015, hydropower generated 16.6% of the world's total electricity and 70% of all renewable electricity, and was expected to increase about 3.1% each year for the next 25 years.
Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013. China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9 percent of domestic electricity use.
The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants. The average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt hour. With a dam and reservoir it is also a flexible source of electricity since the amount produced by the station can be varied up or down very rapidly (as little as a few seconds) to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, and in many cases, has a considerably lower output level of greenhouse gases than fossil fuel powered energy plants.
Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical- and horizontal-axis hydraulic machines. By the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for 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 near Niagara Falls in the U.S. side began to produce electricity in 1881. The first Edison hydroelectric power station, 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 U.S. and Canada. By 1889 there were 200 in the U.S. 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 the International Exhibition of Hydropower and Tourism with over one million visitors. By 1920 as 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 to include flood control, irrigation and navigation. Federal funding became necessary for large-scale development and federally owned corporations, such as 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 U.S. irrigation projects in the early 20th century was now constructing large hydroelectric projects such as the 1928 Hoover Dam. The U.S. Army Corps of Engineers was also involved in hydroelectric development, completing 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 for its power and plenty. Hoover Dam's initial 1,345 MW power station was the world's largest hydroelectric power station in 1936; it was eclipsed by the 6809 MW Grand Coulee Dam in 1942. The Itaipu Dam opened in 1984 in South America as the largest, producing 14,000 MW but was surpassed in 2008 by the Three Gorges Dam in China at 22,500 MW. Hydroelectricity would eventually supply some countries, including Norway, Democratic Republic of the Congo, Paraguay and Brazil, with over 85% of their electricity. The United States currently has over 2,000 hydroelectric power stations that supply 6.4% of its total electrical production output, which is 49% of its renewable electricity.
The technical potential for hydropower development around the world is much greater than the actual production: the percent of potential hydropower capacity that has not been developed is 71% in Europe, 75% in North America, 79% in South America, 95% in Africa, 95% in the Middle East, and 82% in Asia-Pacific. The political realities of new reservoirs in western countries, economic limitations in the third world and the lack of a transmission system in undeveloped areas result in the possibility of developing 25% of the remaining technically exploitable potential before 2050, with the bulk of that being in the Asia-Pacific area. Some countries have highly developed their hydropower potential and have very little room for growth: Switzerland produces 88% of its potential and Mexico 80%.
Most hydroelectric power comes from 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, the excess generation capacity is used to pump water into the higher reservoir. When the demand becomes greater, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially important means of large-scale grid energy storage and improve the daily capacity factor of the generation system. Pumped storage 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. In the United States, run of the river hydropower could potentially provide 60,000 megawatts (80,000,000 hp) (about 13.7% of total use in 2011 if continuously available).
A tidal power station makes use of 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 the world. In Great Britain, there are eight sites that could be developed, which have the potential to generate 20% of the electricity used in 2012.
Large-scale hydroelectric power stations are more commonly seen as the largest power producing facilities in the world, 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.
|1.||Three Gorges Dam||China||22,500|
|2.||Itaipu Dam|| Brazil
Small hydro is the development of 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 of what can be termed small hydro. This may be stretched to 25 MW and 30 MW in Canada and the United States. Small-scale hydroelectricity production grew by 29% from 2005 to 2008, raising the total world small-hydro capacity to 85 GW. Over 70% of this was in China (65 GW), followed by Japan (3.5 GW), the United States (3 GW), and India (2 GW). 
Small hydro stations may be connected to conventional electrical distribution networks as 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 network, 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 the balance between stream flow and power production.
Micro hydro is a term used for 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, is highest in the winter when solar energy is at a minimum.
Pico hydro is a term used for hydroelectric power generation of under 5 kW. It is useful in small, remote communities that require only a small amount of electricity. For example, to power one or two fluorescent light bulbs and a TV or radio for a few homes. Even smaller turbines of 200-300W may power a single home 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 a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground 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:
Efficiency 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 a start-up time of the order of a few minutes. It takes around 60 to 90 seconds to bring a unit from cold start-up to full load; this is much shorter than for gas turbines or steam plants. Power generation can also be decreased quickly when there is a surplus power generation. Hence the limited capacity of hydropower units 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. The average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour. When used as peak power to meet demand, hydroelectricity has a higher value than base power and a much higher value compared to intermittent energy sources.
Hydroelectric stations have long economic lives, with some plants still in service after 50–100 years. Operating labor cost 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 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 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 is initially produced during construction of the project, and some methane is given off annually by reservoirs, hydro generally has the lowest lifecycle greenhouse gas emissions for power generation. Compared to fossil fuels generating an equivalent amount of electricity, hydro displaced three billion tonnes of CO2 emissions in 2011. According to a comparative study by the Paul Scherrer Institute and the University of Stuttgart, hydroelectricity in Europe produces the least amount of greenhouse gases and externality of any energy source. Coming in second place was wind, third was nuclear energy, and fourth was solar photovoltaic. 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 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 a relatively constant water supply. Large hydro dams can control floods, which would otherwise affect people living downstream of the project.
Large reservoirs associated with traditional hydroelectric power stations result in submersion of extensive areas upstream of 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 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. Since turbine gates are often opened intermittently, rapid or even daily fluctuations in river flow are observed.
A 2011 study by the National Renewable Energy Laboratory concluded that hydroelectric plants in the U.S. consumed between 1,425 and 18,000 gallons of water per megawatt-hour (gal/MWh) of electricity generated, through evaporation losses in the reservoir. The median loss was 4,491 gal/MWh, which is higher than the loss for generation technologies that use cooling towers, including concentrating solar power (865 gal/MWh for CSP trough, 786 gal/MWh for CSP tower), coal (687 gal/MWh), nuclear (672 gal/MWh), and natural gas (198 gal/MWh). Where there are multiple uses of reservoirs such as water supply, recreation, and flood control, all reservoir evaporation is attributed to power production.
When water flows it has 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 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 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 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, as it has been noted that the reservoirs of power plants in tropical regions produce substantial amounts of methane. This is due to plant material in flooded areas decaying in an anaerobic environment and forming methane, 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 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 failed in Southern China when more than a year's worth of rain fell within 24 hours. The resulting flood resulted in the deaths of 26,000 people, and another 145,000 from epidemics. Millions were left homeless.
Smaller dams and micro hydro facilities create less risk, but can form continuing hazards even after being decommissioned. For example, the small earthen embankment Kelly Barnes Dam failed in 1977, twenty years after its power station was decommissioned, causing 39 deaths.
Hydroelectricity eliminates the flue gas emissions from fossil fuel combustion, including pollutants such as sulfur dioxide, nitric oxide, carbon monoxide, dust, and mercury in the coal. Hydroelectricity also avoids the hazards of coal mining and the indirect health effects of coal emissions.
Compared to nuclear power, hydroelectricity construction requires altering large areas of the environment while a nuclear power station has a small footprint, and hydro-powerstation failures have caused tens of thousands of more deaths than any nuclear station failure. The creation of Garrison Dam, for example, required Native American land to create Lake Sakakawea, which has a shoreline of 1,320 miles, and caused the inhabitants to sell 94% of their arable land for $7.5 million in 1949.
However, nuclear power is relatively inflexible; although nuclear power can reduce its output reasonably quickly. Since the cost of nuclear power is dominated by its high infrastructure costs, the cost per unit energy goes up significantly with low production. Because of this, nuclear power is mostly used for baseload. By way of contrast, hydroelectricity can supply peak power at much lower cost. Hydroelectricity is thus often used to complement nuclear or other sources for load following. Country examples were they are paired in a close to 50/50 share include the electric grid in Switzerland, the Electricity sector in Sweden and to a lesser extent, Ukraine and the Electricity sector in Finland.
Wind power goes through predictable variation by season, but is intermittent on a daily basis. Maximum wind generation has little relationship to peak daily electricity consumption, the wind may peak at night when power isn't needed or be still during the day when electrical demand is highest. Occasionally weather patterns can result in low wind for days or weeks at a time, a hydroelectric reservoir capable of storing weeks of output is useful to balance generation on the grid. Peak wind power can be offset by minimum hydropower and minimum wind can be offset with maximum hydropower. In this way the easily regulated character of hydroelectricity is used to compensate for the intermittent nature of wind power. Conversely, in some cases wind power can be used to spare water for later use in dry seasons.
In areas that do not have hydropower, pumped storage serves a similar role, but at a much higher cost and 20% lower efficiency. An example of this is Norway's trading with Sweden, Denmark, the Netherlands and possibly Germany or the UK in the future. Norway is 98% hydropower, while it's flatland neighbors are installing wind power.
The ranking of hydro-electric capacity is either by actual annual energy production or by installed capacity power rating. In 2015 hydropower generated 16.6% of the worlds total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generated 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. Brazil, Canada, New Zealand, Norway, Paraguay, Austria, Switzerland, Venezuela, and several other countries have a majority of the internal electric energy production from hydroelectric power. Paraguay produces 100% of its electricity from hydroelectric dams and exports 90% of its production to Brazil and to Argentina. Norway produces 96% of its electricity from hydroelectric sources.
A hydro-electric station rarely operates at its full power rating over a full year; the ratio between annual average power and installed capacity rating is the capacity factor. The installed capacity is the sum of all generator nameplate power ratings.
|% of total |
|Name||Maximum Capacity (MW)||Country||Construction started||Scheduled completion||Comments|
|Belo Monte Dam||11,181||Brazil||March, 2011||2015||Preliminary construction underway.
Construction suspended 14 days by court order Aug 2012
|Siang Upper HE Project||11,000||India||April, 2009||2024||Multi-phase construction over a period of 15 years. Construction was delayed due to dispute with China.|
|Tasang Dam||7,110||Burma||March, 2007||2022||Controversial 228 meter tall dam with capacity to produce 35,446 GWh annually.|
|Xiangjiaba Dam||6,400||China||November 26, 2006||2015||The last generator was commissioned on July 9, 2014|
|Grand Ethiopian Renaissance Dam||6,000||Ethiopia||2011||2017||Located in the upper Nile Basin, drawing complaint from Egypt|
|Jinping 2 Hydropower Station||4,800||China||January 30, 2007||2014||To build this dam, 23 families and 129 local residents need to be moved. It works with Jinping 1 Hydropower Station as a group.|
|Diamer-Bhasha Dam||4,500||Pakistan||October 18, 2011||2023|
|Jinping 1 Hydropower Station||3,600||China||November 11, 2005||2014||The sixth and final generator was commissioned on 15 July 2014|
|Jirau Power Station||3,300||Brazil||2008||2013||Construction halted in March 2011 due to worker riots.|
|Guanyinyan Dam||3,000||China||2008||2015||Construction of the roads and spillway started.|
|Dagangshan Dam||2,600||China||August 15, 2008||2016|
|Tocoma Dam Bolívar State||2,160||Venezuela||2004||2014||This power station would be the last development in the Low Caroni Basin, bringing the total to six power stations on the same river, including the 10,000MW Guri Dam.|
|Ludila Dam||2,100||China||2007||2015||Brief construction halt in 2009 for environmental assessment.|
|Shuangjiangkou Dam||2,000||China||December, 2007||2018||The dam will be 312 m high.|
|Ahai Dam||2,000||China||July 27, 2006||2015|
|Teles Pires Dam||1,820||Brazil||2011||2015|
|Site C Dam||1,100||Canada||2015||2024||First large dam in western Canada since 1984|
|Lower Subansiri Dam||2,000||India||2007||2016|
98-99% of Norway’s electricity comes from hydroelectric plants.
The electricity sector in Sri Lanka has a national grid which is primarily powered by hydro power and thermal heat, with sources such as photovoltaics and wind power in early stages of deployment. Although potential sites are being identified, other power sources such as geothermal, nuclear, peat, solar thermal and wave power are not used in the power generation process for the national grid.The country is expected to achieve 100% electricity generation by renewable energy by 2050.Hydroelectric power in the United States
Hydroelectric power stations in the United States are currently the largest renewable source of energy, but the second for nominal capacity (behind Wind power in the United States). Hydroelectric power produced 35% of the total renewable electricity in the U.S. in 2015, and 6.1% of the total U.S. electricity.According to IEA the United States was the 4th largest producer of hydroelectric power in the world in 2008 after China, Canada and Brazil. Produced hydroelectricity was 282 TWh (2008). It was 8.6% of the world's total hydropower. The installed capacity was 80 GW in 2015. The amount of hydroelectric power generated is strongly affected by changes in precipitation and surface runoff.Hydroelectric stations exist in at least 34 US states. The largest concentration of hydroelectric generation in the US is in the Columbia River basin, which in 2012 was the source of 44% of the nation’s hydroelectricity. Hydroelectricity projects such as Hoover Dam, Grand Coulee Dam, and the Tennessee Valley Authority have become iconic large construction projects.
Of note, however, is that California does not consider power generated from large hydroelectric facilities (facilities greater than 30 megawatts) to meet its strictest definition of "renewable", due to concerns over the environmental impact of large hydroelectric projects. As such, electricity generated from large hydroelectric facilities does not count toward California's strict Renewable Portfolio Standards. Roughly about 10 to 15 percent of California’s energy generation is from large hydroelectric generation that is not RPS-eligible.Hydroelectricity in the United Kingdom
As of 2012, hydroelectric power stations in the United Kingdom accounted for 1.65 GW of installed electrical generating capacity, being 1.8% of the UK's total generating capacity and 18% of UK's renewable energy generating capacity. This includes four conventional hydroelectric power stations and run-of-river schemes for which annual electricity production is approximately 5,000 GWh, being about 1.3% of the UK's total electricity production. There are also pumped-storage hydroelectric power stations providing a further 2.8 GW of installed electrical generating capacity, and contributing up to 4,075 GWh of peak demand electricity annually.The potential for further practical and viable hydroelectricity power stations in the UK is estimated to be in the region of 146 to 248 MW for England and Wales, and up to 2,593 MW for Scotland.
However, by the nature of the remote and rugged geographic locations of some of these potential sites, in national parks or other areas of outstanding natural beauty, it is likely that environmental concerns would mean that many of them would be deemed unsuitable, or could not be developed to their full theoretical potential.
Interest in hydropower in the UK has been renewed in recent years due to new UK and EU targets for reductions in carbon emissions and the promotion of renewable energy power generation through commercial incentives such as the Renewable Obligation Certificate scheme (ROCs) and feed-in tariffs (FITs). Before such schemes, studies to assess the available hydro resources in the UK had discounted a large number of sites for reasons of poor economic or technological viability, but more recent studies in 2008 and 2010 by the British Hydro Association (BHA) identified a larger number of viable sites, due to improvements in the available technology and the economics of ROCs and FITSsSchemes up to 50 kW are eligible for FITs, and schemes over 5 MW are eligible for ROCs. Schemes between 50 kW and 5 MW can choose between either. The UK Government's National Renewable Energy Action Plan of July 2010 envisaged between 40 and 50 MW of new hydropower schemes being installed annually up to 2020. The most recent feedback for new hydro schemes is for 2009, and only about 15 MW of new hydropower was installed during that year.Hydropower
Hydropower or water power (from Greek: ὕδωρ, "water") is power derived from the energy of falling water or fast running water, which may be harnessed for useful purposes. Since ancient times, hydropower from many kinds of watermills has been used as a renewable energy source for irrigation and the operation of various mechanical devices, such as gristmills, sawmills, textile mills, trip hammers, dock cranes, domestic lifts, and ore mills. A trompe, which produces compressed air from falling water, is sometimes used to power other machinery at a distance.In the late 19th century, hydropower became a source for generating electricity. Cragside in Northumberland was the first house powered by hydroelectricity in 1878 and the first commercial hydroelectric power plant was built at Niagara Falls in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower.
Since the early 20th century, the term has been used almost exclusively in conjunction with the modern development of hydroelectric power. International institutions such as the World Bank view hydropower as a means for economic development without adding substantial amounts of carbon to the atmosphere,
but dams can have significant negative social and environmental impacts.List of dams and reservoirs in Dominican Republic
There are numerous dams and reservoirs in the Dominican Republic, which is composed of rivers, lakes, streams, and numerous waterfalls.
The main rivers in the Dominican Republic are the Yaque del Norte, which is the longest in the country at 201 km in length. The second largest and the strongest river is the Yuna River which is 138 km in length and the third largest is the Yaque del Sur which is 136 km in length.
*Actual capacity might vary
**Some rivers have the same name as dams or hydro-electric plants.List of dams and reservoirs in India
This page shows the state-wise list of dams and reservoirs in India. It also includes . Nearly 3200 major / medium dams and barrages had been constructed in India by the year 2012.List of dams and reservoirs in Maharashtra
There are around 1821 notable large dams in state of Maharashtra in India.List of dams and reservoirs in Sri Lanka
The following page lists most dams in Sri Lanka. Most of these dams are governed by the Mahaweli Authority, while the Ceylon Electricity Board operates dams used for hydroelectric power generation. Hydroelectric dams, including small hydros accounts for nearly half of the installed power capacity of Sri Lanka.
Sri Lanka is pockmarked with a large number of irrigation dams with its water resource distributed across nearly the entirety of the island for agricultural purposes via artificial canals and streams. Utilization of hydro resources for agricultural production dates back pre-Colonial era, with current crop productions now largely dependent on these water resources.Lists of hydroelectric power stations
The following are lists of hydroelectric power stations based on the four methods of hydroelectric generation:
List of conventional hydroelectric power stations, hydroelectric generation through conventional dams
List of pumped-storage hydroelectric power stations, hydroelectric generation through pumped-storage
List of run-of-the-river hydroelectric power stations, hydroelectric generation through run-of-the-river hydropower
List of tidal power stations, hydroelectric generation through tidal powerPumped-storage hydroelectricity
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power. Although the losses of the pumping process makes the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest.
Pumped-storage hydroelectricity allows energy from intermittent sources (such as solar, wind) and other renewables, or excess electricity from continuous base-load sources (such as coal or nuclear) to be saved for periods of higher demand. The reservoirs used with pumped storage are quite small when compared to conventional hydroelectric dams of similar power capacity, and generating periods are often less than half a day.
Pumped storage is the largest-capacity form of grid energy storage available, and, as of 2017, the United States Department of Energy Global Energy Storage Database reports that PSH accounts for over 95% of all active tracked storage installations worldwide, with a total installed nameplate capacity of over 184 GW, of which about 25 GW are in the United States. The round-trip energy efficiency of PSH varies between 70%–80%, with some sources claiming up to 87%. The main disadvantage of PSH is the specialist nature of the site required, needing both geographical height and water availability. Suitable sites are therefore likely to be in hilly or mountainous regions, and potentially in areas of outstanding natural beauty, and therefore there are also social and ecological issues to overcome. Many recently proposed projects, at least in the U.S., avoid highly sensitive or scenic areas, and some propose to take advantage of "brownfield" locations such as disused mines.Renewable energy in Afghanistan
Renewable energy in Afghanistan includes biomass, hydropower, solar, and wind power. Afghanistan is a landlocked country surrounded by five other countries. With a population of less than 35 million people, it is one of the lowest energy consuming countries in relation to a global standing. It holds a spot as one of the countries with a smaller ecological footprint. Hydropower is currently the main source of renewable energy due to Afghanistan's geographical location. Its large mountainous environment facilitates the siting of hydroelectric dams (see also list of dams and reservoirs in Afghanistan) and other facets of hydro energy.The renewable energy resource potential of Afghanistan is estimated at over 300,000 MW according to the state's Ministry of Energy and Water.
The country has progressed in the last decade in becoming self sustainable with its use of energy. But it still imports significant amount of electricity from neighboring Uzbekistan, Tajikistan, Iran and Turkmenistan.Another form of renewable energy in Afghanistan is biogas. With the start of biogas, communities have begun to feel the benefits beyond that of the environment through capacity building as well.Renewable energy in Belarus
Renewable energy is a target, and Belarus has a goal to reach 6% generation from renewable energy sources by 2035 (compared to 0.41% in 2013). To support development, private sector developers are eligible for feed-in tariffs to support a wide range of renewable energy sources.Renewable energy in Brazil
As of 2018, renewable energy accounted for 79% of the domestically produced electricity used in Brazil. Brazil relies on hydroelectricity for 65% of its electricity , and the Brazilian government plans to expand the share of biomass and wind energy (currently 6%) as alternatives. Wind energy has the greatest potential in Brazil during the dry season, so it is considered a hedge against low rainfall and the geographical spread of existing hydroelectric resources.
In January 2015, a drought in Brazil that cut water to the country's hydroelectric dams prompted severe energy shortages. This crisis ravaged the country's economy and led to electricity rationing.Brazil held its first wind-only energy auction in 2009, in a move to diversify its energy portfolio. Foreign companies scrambled to take part.
The bidding lead to the construction of 2 gigawatts (GW) of wind production with an investment of about $6 billion over the following two years.
Brazil's technical potential for wind energy is 143 GW due to the country's blustery 7,400 kilometres (4,600 mi) kilometres coastline where most projects are based.
The Brazilian Wind Energy Association and the government have set a goal of achieving 20 GW of wind energy capacity by 2020 from the current 5 GW (2014). The industry hopes the auction will help kick-start the wind-energy sector, which already accounts for 70% of the total in all of Latin America.According to Brazil's Energy Master-plan 2016-2026 (PDE2016-2026), Brazil is expected to install 18,5GW of additional wind power generation, 84% in the North-East and 14% in the South. Brazil started focusing on developing alternative sources of energy, mainly sugarcane ethanol, after the oil shocks in the 1970s.
Brazil's large sugarcane farms helped the development.
In 1985, 91% of cars produced that year ran on sugarcane ethanol.
The success of flexible-fuel vehicles, introduced in 2003, together with the mandatory E25 blend throughout the country, have allowed ethanol fuel consumption in the country to achieve a 50% market share of the gasoline-powered fleet by February 2008.Renewable energy in Chile
Renewable energy in Chile is classified as Conventional and Non Conventional Renewable Energy (NCRE), and includes biomass, hydro-power, geothermal, wind and solar among other energy sources. Most of the time, when referring to Renewable Energy in Chile, it will be the Non Conventional kind.
Chile has considerable geothermal, solar and wind energy resources while fossil fuel resources are limited. In 2016 Non Conventional Renewable Energy provided 7,794 GWh, or 11.4% of the country's total electricity generation. NCRE accounted for 17.2% of the installed electricity generation capacity by the end of 2016.Renewable energy in Ethiopia
Ethiopia generates most of its electricity from renewable energy, mainly hydropower.Renewable energy in Nepal
Renewable energy in Nepal is a sector that is rapidly developing in Nepal.
While Nepal mainly relies on hydro electricity for its energy needs, solar and wind power is being seen as an important supplement to solve its energy crisis.
Nepal is one of three countries with the greatest increases in electricity access from 2006 to 2016, owing to grid-connected and off-grid renewables.Reservoir
A reservoir (from French réservoir – a "tank") is, most commonly, an enlarged natural or artificial lake, pond or impoundment created using a dam or lock to store water.
Reservoirs can be created in a number of ways, including controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, through excavation, or building any number of retaining walls or levees.
Defined as a storage space for fluids, reservoirs may hold water or gasses, including hydrocarbons. Tank reservoirs store these in ground-level, elevated, or buried tanks. Tank reservoirs for water are also called cisterns. Most underground reservoirs are used to store liquids, principally either water or petroleum, below ground.Run-of-the-river hydroelectricity
Run-of-river hydroelectricity (ROR) or run-of-the-river hydroelectricity is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amount of storage, in which case the storage reservoir is referred to as pondage. A plant without pondage is subject to seasonal river flows, thus the plant will operate as an intermittent energy source. Conventional hydro uses reservoirs, which regulate water for flood control and dispatchable electrical power.Variable renewable energy
Variable renewable energy (VRE) is a renewable energy source that is non-dispatchable due to its fluctuating nature, like wind power and solar power, as opposed to a controllable renewable energy source such as hydroelectricity, or biomass, or a relatively constant source such as geothermal power or run-of-the-river hydroelectricity.
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