"Powerful" doesn’t really do this amazing (and VERY controversial) structure justice.
The last 32 generators went into action at the end of July of last year. The gushing water generated by the dam has enough power to generate about 22.5 million kilowatts (22,500 megawatts) of energy, which is equivalent to about FIFTEEN nuclear reactors and, of course, it doesn’t cause concerns regarding radioactive materials being unleashed (which is a very good thing, especially after events like the Chernobyl and Fukushima nuclear disasters). It is also a solution to frequent flooding around Yangtze’s banks.
However! There are concerns about it trapping pollution, spawning Earth-quakes, landslides, uprooting citizens (more than 1.3 million people have already been forced to relocate), and destroying historical locations along with the habitats of endangered animals.
Wondering how this could possibly have an impact on the Earth’s rotation?
Here’s a wonderful source that breaks it down:
"Three Gorges Dam crosses the Yangtze River in Hubei province, China. It is the world’s largest hydroelectric power station by total capacity, which will be 22,500 MW when completed. When the water level is at maximum….it will flood a total area of 632 km2 of land. The reservoir will contain about 39.3 cubic km (9.43 cubic miles) of water. That water will weigh more than 39 trillion kilograms (42 billion tons).
A shift in a mass of that size will impact the rotation of the Earth due to a phenomena known as “the moment of inertia”, which is the inertia of a rigid rotating body with respect to its rotation. The moment of inertia of an object about a given axis describes how difficult it is to change its angular motion about that axis. The longer the distance of a mass to its axis of rotation, the slower it will spin. You may not know it, but you see examples of this in everyday life. For example, a figure skater attempting to spin faster will draw her arms tight to her body, and thereby reduce her moment of inertia. Similarly, a diver attempting to somersault faster will bring his body into a tucked position.
Raising 39 trillion kilograms of water 175 meters above sea level will increase the Earth’s moment of inertia, and thus slow its rotation. However, the impact will be extremely small. NASA scientists calculated the shift of such a mass will increase the length of day by only 0.06 microseconds, and make the Earth only very slightly more round in the middle and more flat on the top. It will also shift the pole position by about two centimeters (0.8 inch). Note that a shift in any object’s mass on the Earth relative to its axis of rotation will change its moment of inertia, although most shifts are too small to be measured (but they can be calculated).”
Not to worry, though. Earth’s rotation changes frequently as a result of the moon gradually receding from the Earth, Earthquakes (like the mega quake in Japan back in 2011), and changes in atmospheric winds and oceanic currents. Furthermore, each year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake.
For Further Reading:
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