4/28/13
The engineers who designed the Three Gorges Dam added a few special features, and for good reason. The first major issue that engineers faced was deciding what size the reservoir should be. Dams that are used for flood preventative purposes have low reservoirs, but hydroelectric dams have large reservoirs. The answer was to keep the reservoir low during the dry seasons. The reason behind the decision was because the dam would release more water during the dry season down stream, which would help farmers during dry seasons. When the rainy seasons come the reservoir begins to fill, which limits the floods and allows the dam to provide more energy.
The engineers who designed the Three Gorges Dam added a few special features, and for good reason. The first major issue that engineers faced was deciding what size the reservoir should be. Dams that are used for flood preventative purposes have low reservoirs, but hydroelectric dams have large reservoirs. The answer was to keep the reservoir low during the dry seasons. The reason behind the decision was because the dam would release more water during the dry season down stream, which would help farmers during dry seasons. When the rainy seasons come the reservoir begins to fill, which limits the floods and allows the dam to provide more energy.
The next feature of the dam is the lock. There are two locks and each
contains five cells. It takes a ship 3 to 4 hours to pass through the lock. The
locks do have a weight limit of 10,000 tons. There is also a ship lift that is
currently under construction. Once completed, the ship lift will be able to
lift boats that are 3000 tons or less. The lift will reduce the time of
crossing the dam to only 40 minutes.
The third and most important feature is the ability of the dam to
withstand an earthquake that registers a 7.0 on the Richter scale. The reason
why this is so important is because the Three Gorges Dam lies on a fault line.
The 1.39 trillion cubic foot reservoir which weighs 42 billion tons puts added
weight onto the fault line causing many tremors. Using Concrete in the
construction of the dam helped the dam withstand seismic activity. The
buttresses along the dam not only push back against the water but also stabilize
the dam against earthquakes, which is the reason why the Dam withstands such
strong quakes.
A purpose of the dam is to generate energy. The feature that enables
this to happen is the 34 generators inside the dam. The 32 main generators each
generate 700 MW of power. Each weighs 6000 metric tons and has a flow rate
ranging between 600 and 950 cubic-meters per second. The turbine connected to
the generator spins 75 times per minute. All of this results in 20 kV of electrical
power from a single generator.
Three Gorges Dam Lock
Is the Three Gorges Dam efficient compared to other electrical power options? Well the Dam has a total of 34 generators that produce 22,500 MW of power. Compared to Nuclear Power Plants this is very large. The largest Nuclear power Plant in the United States is Palo Verde Plant in Arizona. It has three reactors that total only 3,937 MW. The Three Gorges Dam generates approximately 5.7 times the amount of the Palo Verde Plant. But if the Three Gorges Dam is truly efficient, the cost to power ratio will be greater. The Three Gorges Dam cost 22.5 billion dollars to build although most of that money was used to relocate Chinese citizens which gives the dam a ratio of 1000 MW for every billion of dollars spent. The Palo Verde Plant cost 5.9 billion dollars which gives it a ratio of roughly 667 MW for every billion of dollars spent. In conclusion the Three Gorges Dam is more beneficial than a Nuclear Power Plant.
By: Liam Brennan
By: Liam Brennan
