2021 Global Hydroelectric Power Report

Summary
Hydropower is a power generation method that uses the potential energy of water to convert it into electrical energy. Its principle is to use the drop in water level (potential energy) to flow under the action of gravity (kinetic energy), such as leading water from high water sources such as rivers or reservoirs to lower levels. The flowing water drives the turbine to rotate and drive the generator to generate electricity. The high-level water comes from the heat of the sun and evaporates the low-level water, so it can be considered as indirectly using solar energy. Due to its mature technology, it is currently the most widely used renewable energy in human society.
According to the International Commission on Large Dams (ICOLD) definition of a large dam, a dam is defined as any dam with a height exceeding 15 meters (from the lowest point of the foundation to the top of the dam) or a dam with a height between 10 and 15 meters, which meets at least one of the following conditions:
The length of the dam crest shall not be less than 500 meters;

The reservoir capacity formed by the dam shall not be less than 1 million cubic meters;
⑶ The maximum flood flow handled by the dam shall not be less than 2000 cubic meters per second;
The problem of dam foundation is particularly difficult;
The design of this dam is extraordinary.

According to the BP2021 report, global hydropower accounted for 4296.8/26823.2=16.0% of global power generation in 2020, lower than coal-fired power generation (35.1%) and gas power generation (23.4%), ranking third in the world.
In 2020, hydroelectric power generation was the largest in East Asia and the Pacific, accounting for 1643/4370=37.6% of the global total.
The country with the highest hydroelectric power generation in the world is China, followed by Brazil, the United States, and Russia. In 2020, China’s hydropower generation accounted for 1322.0/7779.1=17.0% of China’s total electricity generation.
Although China ranks first in the world in terms of hydroelectric power generation, it is not high in the country’s power generation structure. The countries with the highest proportion of hydropower generation in their total electricity generation in 2020 were Brazil (396.8/620.1=64.0%) and Canada (384.7/643.9=60.0%).
In 2020, China’s power generation was mainly coal-fired (accounting for 63.2%), followed by hydropower (accounting for 17.0%), accounting for 1322.0/4296.8=30.8% of the global total hydropower generation. Although China ranks first in the world in hydropower generation, it has not reached its peak. According to the World Energy Resources 2016 report released by the World Energy Council, 47% of China’s hydropower resources are still undeveloped.

Comparison of Power Structure among the Top 4 Hydroelectric Power Generation Countries in 2020
From the table, it can be seen that China’s hydropower accounts for 1322.0/4296.8=30.8% of the global total hydropower generation, ranking first in the world. However, its proportion to China’s total electricity generation (17%) is only slightly higher than the global average (16%).
There are four forms of hydroelectric power generation: dam type hydroelectric power generation, pumped storage hydroelectric power generation, stream type hydroelectric power generation, and tidal power generation.

Dam type hydroelectric power generation
Dam type hydropower, also known as reservoir type hydropower. A reservoir is formed by storing water in embankments, and its maximum output power is determined by the difference between the reservoir volume, outlet position, and water surface height. This height difference is called head, also known as head or head, and the potential energy of water is directly proportional to the head.
In the mid-1970s, French engineer Bernard Forest de B é lidor published “Building Hydraulics”, which described vertical and horizontal axis hydraulic presses. In 1771, Richard Arkwright combined hydraulics, water framing, and continuous production to play an important role in architecture. Develop a factory system and adopt modern employment practices. In the 1840s, a hydroelectric power network was developed to generate electricity and transmit it to end users. By the end of the 19th century, generators had been developed and can now be coupled with hydraulic systems.

The world’s first hydroelectric project was the Cragside Country Hotel in Northumberland, England in 1878, used for lighting purposes. Four years later, the first private power station was opened in Wisconsin, USA, and hundreds of hydroelectric power stations were subsequently put into operation to provide local lighting.
Shilongba Hydropower Station is the first hydropower station in China, located on the Tanglang River in the outskirts of Kunming City, Yunnan Province. The construction began in July 1910 (Gengxu year) and power was generated on May 28, 1912. The initial installed capacity was 480 kW. On May 25, 2006, Shilongba Hydropower Station was approved by the State Council to be included in the sixth batch of national key cultural relics protection units.
According to REN21′s 2021 report, the global installed capacity of hydropower in 2020 was 1170GW, with China increasing by 12.6GW, accounting for 28% of the global total, higher than Brazil (9%), the United States (7%), and Canada (9.0%).
According to BP’s 2021 statistics, the global hydroelectric power generation in 2020 was 4296.8 TWh, of which China’s hydroelectric power generation was 1322.0 TWh, accounting for 30.1% of the global total.
Hydroelectric power generation is one of the main sources of global electricity production and the leading energy source for renewable energy generation. According to BP’s 2021 statistics, the global electricity production in 2020 was 26823.2 TWh, of which hydroelectric power generation was 4222.2 TWh, accounting for 4222.2/26823.2=15.7% of the global total electricity generation.
This data is from the International Commission on Dams (ICOLD). According to the registration in April 2020, there are currently 58713 dams worldwide, with China accounting for 23841/58713=40.6% of the global total.
According to BP’s 2021 statistics, in 2020, China’s hydropower accounted for 1322.0/2236.7=59% of China’s renewable energy electricity, occupying the dominant position in renewable energy power generation.
According to the International Hydropower Association (iha) [2021 Hydropower Status Report], in 2020, the total hydropower generation in the world will reach 4370TWh, of which China (31% of the global total), Brazil (9.4%), Canada (8.8%), the United States (6.7%), Russia (4.5%), India (3.5%), Norway (3.2%), Türkiye (1.8%), Japan (2.0%), France (1.5%) and so on will have the largest hydropower generation.

In 2020, the region with the most hydroelectric power generation in the world was East Asia and the Pacific, accounting for 1643/4370=37.6% of the global total; Among them, China is particularly prominent, accounting for 31% of the global total, accounting for 1355.20/1643=82.5% in this region.
The amount of hydroelectric power generation is proportional to the total installed capacity and the installed capacity of pumped storage. China has the world’s largest hydroelectric power generation capacity, and of course, its installed capacity and pumped storage capacity also rank first in the world. According to the International Hydroelectric Association (iha) 2021 Hydroelectric Power Status Report, China’s installed capacity of hydropower (including pumped storage) reached 370160MW in 2020, accounting for 370160/1330106=27.8% of the global total, ranking first in the world.
The Three Gorges Hydropower Station, the world’s largest hydropower station, has the largest hydropower generation capacity in China. The Three Gorges Hydropower Station uses 32 Francis turbine, each 700MW, and two 50MW turbines, with an installed capacity of 22500MW and a dam height of 181m. The power generation capacity in 2020 will be 111.8 TWh, and the construction cost will be ¥ 203 billion. It will be completed in 2008.
Four world-class hydropower stations have been built in the Yangtze River Jinsha River section of Sichuan: Xiangjiaba, Xiluodu, Baihetan, and Wudongde. The total installed capacity of these four hydropower stations is 46508MW, which is 46508/22500=2.07 times the installed capacity of the Three Gorges Hydropower Station of 22500MW. Its annual power generation is 185.05/101.6=1.82 times. Baihetan is the second largest hydropower station in China after the Three Gorges hydropower station.
At present, the Three Gorges Hydropower Station in China is the world’s largest power plant. Among the top 12 largest hydropower stations in the world, China holds six seats. The Itaipu Dam, which has long been ranked second in the world, has been pushed to third place by Baihetan Dam in China.

The world’s largest conventional hydroelectric power station in 2021
There are 198 hydropower stations with an installed capacity of over 1000MW in the world, of which China accounts for 60, accounting for 60/198=30% of the world total. Next are Brazil, Canada, and Russia.
There are 198 hydropower stations with an installed capacity of over 1000MW in the world, of which China accounts for 60, accounting for 60/198=30% of the world total. Next are Brazil, Canada, and Russia.
There are 60 hydropower stations with an installed capacity of over 1000MW in China, mainly 30 in the Yangtze River Basin, accounting for half of China’s hydropower stations with an installed capacity of over 1000MW.

Hydroelectric power plants with an installed capacity of over 1000MW put into operation in China
Going upstream from the Gezhouba Dam and crossing the tributaries of the Yangtze River via the Three Gorges Dam, this is the main force of China’s power transmission from west to east, and also the world’s largest cascade power station: there are about 90 hydropower stations in the mainstream of the Yangtze River, including Gezhouba Dam and the Three Gorges, 10 in the Wujiang River, 16 in the Jialing River, 17 in the Minjiang River, 25 in the Dadu River, 21 in the Yalong River, 27 in the Jinsha River, and 5 in the Muli River.
Tajikistan has the world’s highest natural dam, the Usoi Dam, with a height of 567m, which is 262m higher than the existing highest artificial dam, the Jinping Level 1 Dam. The Usoi Dam was formed on February 18, 1911, when a 7.4 magnitude earthquake occurred in Sarez, and a natural landslide dam along the Murgab River blocked the flow of the river. It triggered large-scale landslides, blocked the Murgab River, and formed the world’s tallest dam, the Usoi Dam, forming Lake Sares. Unfortunately, there are no reports of hydroelectric power generation.
In 2020, there were 251 dams with the highest height exceeding 135m in the world. The highest dam currently is the Jinping-I Dam, an arched dam with a height of 305 meters. Next is the Nurek Dam on the Vakhsh River in Tajikistan, with a length of 300m.

The world’s highest dam in 2021
At present, the world’s tallest dam, the Jinping-I Dam in China, has a height of 305 meters, but three dams under construction are preparing to surpass it. The ongoing Rogun Dam will become the world’s tallest dam, located on the Vakhsh River in southern Tajikistan. The dam is 335m high and construction began in 1976. It is estimated to be put into operation from 2019 to 2029, with a construction cost of 2-5 billion US dollars, an installed capacity of 600-3600MW, and an annual power generation of 17TWh.
The second is the Bakhtiari Dam under construction on the Bakhtiari River in Iran, with a height of 325m and 1500MW. The project cost is 2 billion US dollars and an annual power generation of 3TWh. The third largest dam on the Dadu River in China is the Shuangjiangkou Dam, with a height of 312m.

A dam exceeding 305 meters is being constructed
The highest gravity dam in the world in 2020 was the Grande Dixence Dam in Switzerland, with a height of 285m.
The largest dam in the world with the highest water storage capacity is the Kariba Dam on the Zambezi River in Zimbabwe and Zambezi. It was built in 1959 and has a water storage capacity of 180.6 km3, followed by the Bratsk Dam on the Angara River in Russia and the Akosombo Dam on Lake Kanawalt, with a storage capacity of 169 km3.

The world’s largest reservoir
The Three Gorges Dam, located on the mainstream of the Yangtze River, has the largest water storage capacity in China. It was completed in 2008 and has a water storage capacity of 39.3km3, ranking 27th in the world.
The largest reservoir in China
The largest dam in the world is the Tarbela Dam in Pakistan. It was built in 1976 and has a structure of 143 meters high. The dam has a volume of 153 million cubic meters and an installed capacity of 3478MW.
The largest dam body in China is the Three Gorges Dam, which was completed in 2008. The structure is 181 meters high, the dam volume is 27.4 million cubic meters, and the installed capacity is 22500 MW. Ranked 21st in the world.

The world’s largest dam body
The Congo River Basin is mainly composed of the Democratic Republic of Congo. The Democratic Republic of Congo can develop a national installed capacity of 120 million kilowatts (120000 MW) and an annual power generation of 774 billion kilowatt hours (774 TWh). Starting from Kinshasa at an altitude of 270 meters and reaching the section of Matadi, the riverbed is narrow, with steep banks and turbulent water flow. The maximum depth is 150 meters, with a drop of about 280 meters. The water flow changes regularly, which is extremely beneficial for the development of hydropower. Three levels of large-scale hydropower stations have been planned, with the first level being the Pioka dam, located on the border between the Democratic Republic of Congo and the Republic of Congo; The second level Grand Inga Dam and the third level Matadi dam are both located in the Democratic Republic of Congo. The Pioka Hydropower Station utilizes a water head of 80 meters and plans to install 30 units, with a total capacity of 22 million kilowatts and an annual power generation of 177 billion kilowatt hours, with the Democratic Republic of Congo and the Republic of Congo receiving half each. Matadi Hydropower Station utilizes a water head of 50 meters and plans to install 36 units, with a total capacity of 12 million kilowatts and an annual power generation of 87 billion kilowatt hours. The Yingjia rapids section, with a drop of 100 meters within 25 kilometers, is the river section with the most concentrated hydropower resources in the world.
There are more hydroelectric power stations in the world than the Three Gorges Dam that have not yet been completed
The the Yarlung Zangbo River is the longest plateau river in China, located in the Tibet Autonomous Region, and one of the highest rivers in the world. Theoretically, after the completion of the Yarlung Zangbo River Hydropower Station, the installed capacity will reach 50000 MW, and the power generation will be three times of that of the Three Gorges Dam (98.8 TWh), reaching 300 TWh, which will be the largest power station in the world.
The the Yarlung Zangbo River is the longest plateau river in China, located in the Tibet Autonomous Region, and one of the highest rivers in the world. Theoretically, after the completion of the Yarlung Zangbo River Hydropower Station, the installed capacity will reach 50000 MW, and the power generation will be three times of that of the Three Gorges Dam (98.8 TWh), reaching 300 TWh, which will be the largest power station in the world.
The the Yarlung Zangbo River was renamed “Brahmaputra River” after flowing out of the territory of Luoyu and into India. After flowing through Bangladesh, it was renamed “Jamuna River”. After converging with the Ganges River in its territory, it flowed into the Bay of Bengal in the Indian Ocean. The total length is 2104 kilometers, with a river length of 2057 kilometers in Tibet, a total drop of 5435 meters, and an average slope ranking first among major rivers in China. The basin is elongated in an east-west direction, with a maximum length of over 1450 kilometers from east to west and a maximum width of 290 kilometers from north to south. The average elevation is about 4500 meters. The terrain is high in the west and low in the east, with the lowest in the southeast. The total area of the river basin is 240480 square kilometers, accounting for 20% of the total area of all river basins in Tibet, and about 40.8% of the total area of the outflow river system in Tibet, ranking fifth among all river basins in China.
According to 2019 data, the countries with the highest per capita electricity consumption in the world are Iceland (51699 kWh/person) and Norway (23210 kWh/person). Iceland relies on geothermal and hydroelectric power generation; Norway relies on hydropower, which accounts for 97% of Norway’s electricity production structure.
The energy structure of the landlocked countries Nepal and Bhutan, which are close to Tibet in China, does not rely on fossil fuels, but rather on their rich hydraulic resources. Hydroelectric power is not only utilized domestically, but also exported.

Pumped storage hydroelectric power generation
Pumped storage hydropower is an energy storage method, not a production method of electricity. When the demand for electricity is low, the excess electricity production capacity continues to generate electricity, driving the electric pump to pump water to a high level for storage. When the demand for electricity is high, the high level water is used for power generation. This method can improve the utilization rate of generator sets and is very important in business.
Pumped storage is an important component of modern and future clean energy systems. The significant increase in renewable energy sources such as wind and solar energy, coupled with their replacement of traditional generators, has brought increasing pressure to the power grid and emphasized the necessity of pumped storage “water batteries”.
The amount of hydroelectric power generation is directly proportional to the installed capacity of pumped storage and is related to the amount of pumped storage. In 2020, there were 68 operating and 42 under construction worldwide.
China’s hydroelectric power generation ranks first in the world, therefore the number of pumped storage power stations in operation and under construction ranks first in the world. Next are Japan and the United States.

The world’s largest pumped storage power station is the Bath County Pumped Storage Station in the United States, with an installed capacity of 3003MW.
The largest pumped storage power station in China is the Huishou Pumped Storage Power Station, with an installed capacity of 2448MW.
The second largest pumped storage power station in China is the Guangdong Pumped Storage Power Station, with an installed capacity of 2400MW.
China’s pumped storage power plants under construction rank first in the world. There are three stations with an installed capacity of over 1000MW: Fengning Pumped Storage Power Station (3600MW, completed from 2019 to 2021), Jixi Pumped Storage Power Station (1800MW, completed in 2018), and Huanggou Pumped Storage Power Station (1200MW, completed in 2019).
The world’s highest elevation pumped storage power plant is the Yamdrok Hydropower Station, located in Tibet, China, at an altitude of 4441 meters.

Stream hydroelectric power generation
Run of the river hydropower (ROR), also known as runoff hydropower, is a form of hydroelectric power that relies on hydropower but only requires a small amount of water or does not require the storage of large amounts of water for power generation. River flow hydroelectric power generation almost completely does not require water storage or only requires the construction of very small water storage facilities. When constructing small water storage facilities, these water storage facilities are called adjustment pools or forepools. Due to the lack of large-scale water storage facilities, stream power generation is highly sensitive to seasonal water volume changes in the source of water. Therefore, stream power plants are usually defined as intermittent energy sources. If a regulating pool is built in a stream power plant that can regulate water flow at any time, it can be used as a peak shaving power plant or a base load power plant.
The largest Sichuan flow hydropower station in the world is the Jirau Dam on the Madeira River in Brazil. The dam is 63m high, 1500m long, and 3075MW installed capacity. It was completed in 2016.
The third largest stream hydroelectric power plant in the world is the Chief Joseph Dam on the Columbia River in the United States, with a height of 72 meters, a length of 1817 meters, an installed capacity of 2620 MW, and an annual power generation of 9780 GWh. It was completed in 1979.
The largest Sichuan style hydropower station in China is the Tianshengqiao II Dam, located on the Nanpan River. The dam has a height of 58.7m, a length of 471m, a volume of 4800000m3, and an installed capacity of 1320MW. It was completed in 1997.

Tidal power generation
Tide power is generated by the rise and fall of ocean water levels caused by tides. Generally, reservoirs are built to generate electricity, but there are also direct uses of tidal water flow to generate electricity. There are not many places globally suitable for tidal power generation, and there are eight places in the UK that are estimated to have the potential to meet 20% of the country’s electricity demand.
The world’s first tidal power plant was the Lance tidal power plant, located in Lance, France. It was built from 1960 to 1966 for 6 years. The installed capacity is 240MW.
The world’s largest tidal power station is the Sihwa Lake Tidal Power Station in South Korea, with an installed capacity of 254MW and was completed in 2011.
The first tidal power station in North America is Annapolis Royal Generating Station, which is located in Royal, Annapolis, Nova Scotia, Canada, at the entrance of Bay of Fundy. The installed capacity is 20MW and was completed in 1984.
The largest tidal power station in China is Jiangxia Tidal Power Station, which is located in the south of Hangzhou, with an installed capacity of only 4.1MW and 6 sets. It started operation in 1985.
The first in stream tidal current generator of the North American Rock Tidal Power Demonstration Project was installed in Vancouver Island, Canada, in September 2006.
At present, the world’s largest tidal power project, MeyGen (MeyGen tidal energy project), is being built in Pentland Firth, northern Scotland, with an installed capacity of 398MW and is expected to be completed in 2021.
Gujarat, India plans to build the first commercial tidal power station in South Asia. A power plant with an installed capacity of 50MW was installed in the Gulf of Kutch on the west coast of India, and construction began in early 2012.
The planned Penzhin Tidal Power Plant Project on the Kamchatka Peninsula in Russia has an installed capacity of 87100MW and an annual power generation capacity of 200TWh, making it the world’s largest tidal power plant. Once completed, the Pinrenna Bay Tidal Power Station will have four times the installed capacity of the current Three Gorges Power Station.