In 2018, 1 single power plant produced more energy than the world’s largest coal and gas-powered plants combined. Rather than using finite fossil fuels, this colossal plant relied on a time-tested renewable energy source: Running water. Stretching over 2.3 km, The Three Gorges Dam of China is the biggest hydroelectric plant and the largest dam globally. It’s capable of manufacturing more energy than any other power plant on Earth. So what makes the Three Gorges Dam capable of manufacturing this much energy? And how do hydroelectric plants operate?
How do hydroelectric dams work
The hydroelectric dam is simply a big gateway. It redirects the river’s watercourse through an oversized tube called a penstock. Running water passes through the penstock and turns turbine blades, Connected to a generator next to a neighboring power station. The blades’ movement spins a coil of wire inside a magnetic field, which produces a steady supply of electricity. Because the penstocks can be closed at any time, the dam can store excess water during stormy seasons till the dry season comes.
This stored water allows the hydroelectric dams to create electricity no matter how the weather will be. The barriers also prevent floods from happening further downstream. These benefits have long appealed to the Chinese province of Hubei, located near the Yangtze river basin. This area was prone to deadly floods during the rainy season when the Yangtze river’s flow is most potent. The plans revolved around building a dam to divert this volatile waterway into a stable power source during the 20th century.
The advantages and disadvantages of The Three Gorges Dam
When construction began in 1994, the plans were excellent. The dam would contain 32 turbines, 12 more turbines than the previous record-holder, Itaipu Dam in South America. The turbines would create and supply energy to two independent power plants, Each connected by a series of wires spanning hundreds of kilometers. The electricity supplied from the Three Gorges reaches power grids as far away as Shanghai, which is more than 1100 kilometers. The human costs of this ambitious Megaproject, however, were steep. To create the dam’s reservoir, the workers needed to flood over 600 square kilometers of land upstream.
There has also been a rise in mudslides within the area. In the first four months of 2010 alone, there have been no fewer than ninety-seven serious incidents caused by erosion in the reservoir. Now the Three Gorges Dam was always visiting be a balance between the positive and also the negative. Aside from human displacement, the other significant impact has been on the environment.
Environmentalists warned that the dam would seriously affect nutrients downstream and sediment flows from the very beginning. This is likely to have enormous ramifications on the ecosystem in the Yangtze neighboring rivers, as well as seacoast areas.
A report in 2006 fans that ratios of silicon to nitrogen in brackish coastal waters fell from 1.5 in 1998 to 0.4 in 2004. A change caused significant damage to marine life in coastal areas, resulting in the further depletion of fish numbers. Further, sediment loading, which measures solid matter carried by river, was found in places to be half of the pre-dam levels, which likely led to increased erosion in tidal wetlands, risking further landslides.
This area included 13 cities and hundreds of villages. And over 1000 historical and archaeological places. The construction has displaced about 1.4 million people, and the government’s relocation programs were never enough. Many objected to the controversial creation, But others have estimated that the lives this dam is saving by stopping the floods outweigh the displacement shock.
Moreover, raising the water level upstream would improve the river’s navigability, increases the shipping capacity, and transform the region into a hub of port towns.
When the project was completed in 2012, China became the biggest electricity provider in the world. In 2018, the dam produced 101.6 billion kilowatt-hours. That’s enough electricity to power 2% of China for an entire year or power New York City for about two years. However, two years ago, another dam less than half the size produced more electricity.
The Three Gorges Dam v/s The Itaipu Dam
Despite the Three Gorges being the largest dam in the world record, The Itaipu Dam located on Brazil and Paraguay’s border still produced more energy. To understand why Itaipu outperformed the Three Gorges Dam, we need to estimate the two factors determining a dam’s energy output. The primary is that the number of turbines. The Three Gorges has the world’s highest installed turbine capacity, 32 compared to 20 of Itaipu, which shows that it can create 50% more energy than Itaipu.
But the second factor is the strength and frequency of the water, which flows through the turbines. The Three Gorges Dam includes rugged in-depth and narrow valleys. However, seasonal Yangtze river changes prevent the dam from reaching its maximum possible production. In comparison, Itaipu Dam is located atop what was previously the Earth’s largest waterfall by volume. Although the dam’s creation destroyed this natural wonder, water’s constant flow allows Itaipu to generate energy regularly each year.
This rivalry between the two dams is far from over. Other projects like The Inga Falls Dam in the Democratic Republic of the Congo[DRC] are also competing for the most powerful power plants’ title. But regardless of what the future holds, governments must ensure that the human and environmental impact is as sustainable as its energy.
Learn more here : The Three Gorges Dam