Three Gorges Dam: Largest power station in the world and its facts

Three Gorges Dam: Largest power station in the world and its facts

Hello guys this time we bring something from engineering marvels in the world, this is the largest hydroelectric power generation dam known as Three Gorges Dam.

Three gorges dam
Three gorges dam

The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in Yiling District, Yichang, Hubei province, China. The Three Gorges Dam is the world’s largest power station in terms of installed capacity (22,500 MW).

Except for a ship lift, the dam project was completed and fully functional as of July 4, 2012, when the last of the main water turbines in the underground plant began production. The ship lift was complete in December 2015. Each main water turbine has a capacity of 700 MW. The dam body was completed in 2006. Coupling the dam’s 32 main turbines with two smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam is 22,500 MW.




As well as producing electricity, the dam is intended to increase the Yangtze River’s shipping capacity and reduce the potential for floods downstream by providing flood storage space. The Chinese government regards the project as a historic engineering, social and economic success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions.
However, the dam flooded archaeological and cultural sites and displaced some 1.3 million people, and is causing significant ecological changes, including an increased risk of landslides.

In The Past

A large dam across the Yangtze River was originally envisioned by Sun Yat-sen in The International Development of China, in 1919. He stated that a dam capable of generating 30 million horsepower (22 GW) was possible downstream of the Three Gorges.

In 1932, the Nationalist government, led by Chiang Kai-shek, began preliminary work on plans in the Three Gorges. In 1939, Japanese military forces occupied Yichang and surveyed the area. A design, the Otani plan, was completed for the dam in anticipation of a Japanese victory over China.

Specifications

When the water level is at its maximum of 175 metres (574 ft) above sea level, which is 110 metres (361 ft) higher than the river level downstream, the dam reservoir is on average about 660 kilometres (410 mi) in length and 1.12 kilometres (3,700 ft) in width. It contains 39.3 km3 (31,900,000 acre·ft) of water and has a total surface area of 1,045 square kilometres (403 sq mi).

gorges dam
gorges dam

On completion, the reservoir flooded a total area of 632 square kilometres (244 sq mi) of land, compared to the 1,350 square kilometres (520 sq mi) of reservoir created by the Itaipu Dam.

Economics

The government estimated that the Three Gorges Dam project would cost 180 billion yuan (US$22.5 billion). By the end of 2008, spending had reached 148.365 billion yuan, among which 64.613 billion yuan was spent on construction, 68.557 billion yuan on relocating affected residents, and 15.195 billion yuan on financing.




It is estimated that the construction cost will be recovered when the dam has generated 1,000 terawatt-hours (3,600 PJ) of electricity, yielding 250 billion yuan. Full cost recovery is expected to occur ten years after the dam starts full operation.

As of December 20, 2013, the full cost of the Three Gorges Dam project has been recovered.

Power Generation Capacity

Power generation is managed by China Yangtze Power, a listed subsidiary of China Three Gorges Corporation (CTGC) — a Central Enterprise SOE administered by SASAC. The Three Gorges Dam is the world’s largest capacity hydroelectric power station with 34 generators: 32 main generators, each with a capacity of 700 MW, and two plant power generators, each with capacity of 50 MW, making a total capacity of 22,500 MW.

Among those 32 main generators, 14 are installed in the north side of the dam, 12 in the south side, and the remaining six in the underground power plant in the mountain south of the dam. The expected annual electricity generation will be over 100 TWh.

Power Generators

The main generators weigh about 6,000 tonnes each and are designed to produce more than 700 MW of power. The designed head of the generator is 80.6 meters (264 ft). The flow rate varies between 600–950 cubic metres per second (21,000–34,000 cu ft/s) depending on the head available. The greater the head, the less water needed to reach full power.

Three Gorges uses Francis turbines. Turbine diameter is 9.7/10.4 m (VGS design/Alstom’s design) and rotation speed is 75 revolutions per minute. Rated power is 778 MVA, with a maximum of 840 MVA and a power factor of 0.9. The generator produces electrical power at 20 kV.

The outer diameter of the generator stator is 21.4/20.9 m. The inner diameter is 18.5/18.8 m. The stator, the biggest of its kind, is 3.1/3 m in height. Bearing load is 5050/5500 tonnes. Average efficiency is over 94%, and reaches 96.5%.

Facts About Three Gorges Dam

1. 1.3 Million People Were Relocated in Order for the Three Gorges Dam to Be Built

a total of 1.3 million people had to be relocated from their homes. This is one of the Three Gorges Dam facts which surprises many people. That roughly equates to 1,600 villages, spread across 140 towns and 13 cities.

2. The Dam Will Actually Slow the Rotation of Planet Earth by 0.66 microseconds

The sheer amount of water that was moved to create the dam, and the place in which it has been relocated to, means that it will literally slow the rotation of our planet. This is another example of Three Gorges Dam facts which are eye opening. The reservoir will hold just over 9.4 cubic miles of water, spread over 650 miles. The total weight of the water in the dam will be 85 trillion pounds. A mass that size will create something known as a moment of inertia , because the water in the reservoir will be raised to 575 feet above sea level – this means that on average our days will lengthen by 0.66 of a microsecond!

3. Since Its Inception, Strange Geological Phenomena Have Occurred

The reservoir and dam were partially completed in 2006, and since that time there have been steady reports of more landslides occurring, a general deterioration of the surrounding environment and more instances of a degradation in the quality of the water, with increases in incidences of algae forming.

4. It Was Built to Control Flooding

Many people ask why was the Three Gorges Dam built? Well, it was constructed to control flooding. But since it was completed, the Yangtze has actually flooded more often, with the year 2010 (some two years after the dam’s completion), being the worst on record for flooding events. In one of the worst floods, some 500 people were killed in North China, resulting in an entire village being wiped out.

5. The Three Gorges Dam Is a Huge Reservoir that Has actually Created Drought

You’d imagine building a reservoir would help to eliminate drought, but in actual fact, some people believe the Three Gorges Dam has caused problems with water. This is another of the Three Gorges Dam facts that is quite alarming. At the current moment in time, China has the largest population of any country in the world at 1.3 billion people. Hundreds of millions of Chinese people have no, or limited, access to clean drinking water – a worrying statistic.

6. The Inception of the Dam goes Back 90 Years – Much Further than Many Think

Although the building and construction has taken place within recent years, the inception and ideas for the project actually came into being some 90 years ago. It was the first proper President of the Republic of China, Sun Yan-set, who had the idea, but it wasn’t until the mid-part of the 20th century that firm plans were put into place when Mao Zedong spoke of his vision for the project to take place. However, it was 1994 before construction began properly.

7. It Is the World’s Largest Hydroelectric power Plant

The Three Gorges Dam facts and figures surrounding its output are truly astonishing. It has 26 turbine generator sets, which will each be able to produce 700,000 kilowatts. In total, it will have a capacity of 18.2 million kilowatts. In addition to this, it will be connected to the hydroelectric grids in Central and Eastern China and its aim is to increase the stability of the power supply to these regions.

8. The Dam Is Made With 510,000 Tons of Steel

It is built entirely of steel and concrete, and during its construction it used 510,000 tons of steel. To put this into context, that’s enough to build the Eiffel Tower 60 times over! Many will have heard the fable that the Great Wall of China is visible from the moon; well, it is also alleged that the Three Gorges Dam is visible from there, too.

9. In the Event of a Natural Disaster, 360 Million Lives Might Be in Danger

The Three Gorges Dam pros and cons have caused consternation among many. Experts are at pains to point out that the dam could easily withstand a large earthquake. However, if the worst was to happen and it did collapse, there is the potential for 360 million lives to be put in danger – that’s basically anyone living within the catchment of the Yangtze River. That’s a truly frightening thought and something that many are worried about, though the same experts say it is unlikely this would ever occur.

10. Despite all Its Problems, It Has Improved China’s Emissions Record

The Three Gorges Dam will be able to reduce coal consumption by almost 31 million tonnes per year, which would end up resulting in 100 million tonnes less of Greenhouse Gas Emissions, one million tonnes less of sulphur dioxide, 370,000 tonnes less of nitric oxide, and one million tonnes less of dust. Hydropower is believed to save an incredible amount of time and money in order to mine, wash and move coal in and around Northern China. It has increased the Yangtze River’s barge capacity six times over, and reduced carbon emissions by well over six million tonnes. It is believed to be a much more environmentally friendly way of transporting goods than trucking.

 

 

 

 

 

 

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