ClassX Video Lessons Building the world’s largest (and most controversial) power plant – Alex Gendler
In 2018, a single power plant outperformed the largest coal and gas plants combined in terms of energy production. This remarkable plant, instead of using limited fossil fuels, harnessed the power of running water. Known as the Three Gorges Dam in China, it stretches over 2.3 kilometers and is the largest hydroelectric plant in the world, capable of generating more energy than any other power plant on Earth.
The Three Gorges Dam operates as a massive gate that redirects the natural flow of a river through a pipe called a penstock. As water rushes through the penstock, it turns the blades of a turbine connected to a generator in a nearby power station. This movement spins coils of wire inside a magnetic field, creating a continuous supply of electricity. Additionally, the dam can seal the penstocks to store excess water during storms and release it during dry periods, allowing it to produce power consistently while also preventing downstream flooding.
Located near the Yangtze River basin in China’s Hubei Province, the dam has been particularly beneficial in controlling severe flooding during rainy seasons. Plans for this ambitious project circulated throughout the 20th century, and construction began in 1994. The dam was designed to house 32 turbines, surpassing the previous record holder, South America’s Itaipu Dam. These turbines supply energy to two power stations, connecting to a vast network of cables that reach as far as Shanghai.
However, the project came with significant human costs. To create the dam’s reservoir, over 600 square kilometers of land upstream were flooded, affecting 13 cities, hundreds of villages, and over 1,000 historical and archaeological sites. Approximately 1.4 million people were displaced, and the government’s relocation efforts were criticized as inadequate. While many opposed the construction, others argued that the flood protection benefits outweighed the displacement trauma. Additionally, raising the water level upstream improved river navigation, increased shipping capacity, and transformed the region into thriving port towns.
Completed in 2012, the Three Gorges Dam made China the world’s largest electricity producer. By 2018, it generated 101.6 billion kilowatt-hours, enough to power nearly 2% of China for a year or New York City for almost two years. Despite its impressive scale, the Itaipu Dam, which is less than half the size, produced more electricity two years earlier.
Two main factors determine a dam’s energy output: the number of turbines and the force and frequency of water flow. The Three Gorges Dam has the highest installed turbine capacity globally, theoretically capable of producing over 50% more power than Itaipu. However, seasonal changes in the Yangtze River prevent it from reaching its maximum potential. In contrast, the Itaipu Dam, built over what was once the world’s largest waterfall by volume, benefits from a constant water flow, allowing it to generate more power consistently.
The competition between these dams continues, with projects like the Inga Falls Dam in the Democratic Republic of Congo also vying for the title of the most powerful power plant. As we look to the future, it is crucial for governments to ensure that the environmental and human impacts of power plants are as sustainable as the energy they produce.
Research the process of hydroelectric power generation, focusing on the Three Gorges Dam. Create a presentation that explains how the dam generates electricity, including the role of the penstock, turbines, and generators. Use diagrams and visuals to enhance your explanation, and present your findings to the class.
Participate in a class debate about the benefits and challenges of the Three Gorges Dam. Divide into two groups: one supporting the dam for its energy production and flood control, and the other opposing it due to environmental and human impacts. Prepare arguments and evidence to support your position, and engage in a respectful debate with your classmates.
Analyze a case study comparing the Three Gorges Dam with the Itaipu Dam. Examine factors such as energy output, environmental impact, and social consequences. Write a report summarizing your analysis and suggest improvements for future hydroelectric projects based on your findings.
Design your own sustainable hydroelectric dam. Consider innovative solutions to minimize environmental and social impacts while maximizing energy production. Create a model or detailed drawings of your design, and explain how it addresses the challenges faced by existing dams like the Three Gorges Dam.
Take a virtual tour of the Three Gorges Dam using online resources and videos. Observe the structure, machinery, and surrounding environment. Write a reflection on what you learned from the tour, including any surprising facts or insights about the dam’s operation and impact.
In 2018, a single power plant produced more energy than the world’s largest coal-powered and gas-powered plants combined. Instead of relying on finite fossil fuels, this powerful plant utilized a renewable energy source: running water. Stretching over 2.3 kilometers, China’s Three Gorges Dam is not only the world’s largest hydroelectric plant but is also capable of producing more energy than any other power plant on Earth.
So, what enables the Three Gorges Dam to generate such immense power? A hydroelectric dam functions as a large gate that redirects a river’s natural flow through a pipe called a penstock. The rushing water flows through the penstock and turns the blades of a turbine, which is connected to a generator in an adjacent power station. The movement of the blades spins coils of wire inside a magnetic field, producing a steady supply of electricity. Additionally, because the penstocks can be sealed at any time, a dam can hold back excess water during stormy seasons and save it for drier periods. This capability allows hydroelectric dams to produce power regardless of the weather while also preventing floods downstream.
These advantages have been particularly beneficial for China’s Hubei Province, located near the Yangtze River basin, which is prone to severe flooding during rainy seasons. Plans to construct a dam to stabilize this volatile waterway into a reliable power source circulated throughout the 20th century. When construction finally began in 1994, the plans were ambitious. The dam would house 32 turbines—12 more than the previous record holder, South America’s Itaipu Dam. These turbines would supply energy to two separate power stations, connecting to a network of cables spanning hundreds of kilometers. Electricity from the Three Gorges Dam would reach power grids as far away as Shanghai.
However, the human costs of this project were significant. To create the dam’s reservoir, workers needed to flood over 600 square kilometers of land upstream, which included 13 cities, hundreds of villages, and over 1,000 historical and archaeological sites. The construction displaced approximately 1.4 million people, and the government’s relocation programs were widely viewed as inadequate. While many opposed the construction, others believed that the lives saved by the dam’s flood protection would outweigh the trauma of displacement. Furthermore, raising the water level upstream would enhance the river’s navigability, increase shipping capacity, and transform the region into prosperous port towns.
When the project was completed in 2012, China became the world’s largest producer of electricity. In 2018, the dam generated 101.6 billion kilowatt-hours, enough electricity to power nearly 2% of China for one year or New York City for almost two years. This is an impressive amount of energy. Yet, two years earlier, another dam less than half the size generated more electricity. Despite the Three Gorges Dam’s record-setting scale, the Itaipu Dam still produced more power.
To understand why Itaipu can outperform Three Gorges, we need to consider two factors that determine a dam’s energy output. The first is the number of turbines. Three Gorges has the highest installed turbine capacity in the world, meaning it is theoretically capable of producing over 50% more power than Itaipu. The second factor is the force and frequency of water moving through those turbines. While Three Gorges spans several deep, narrow ravines with powerful water flow, the seasonal changes in the Yangtze River prevent the dam from reaching its theoretical maximum output. In contrast, the Itaipu Dam is situated atop what was previously the planet’s largest waterfall by volume. Although the dam’s construction altered this natural wonder, the constant flow of water allows Itaipu to consistently generate more power each year.
This competition between dams is ongoing, with other projects like the Inga Falls Dam in the Democratic Republic of Congo also aiming for the title of the most powerful power plant. Regardless of what the future holds, it is essential for governments to ensure that a power plant’s environmental and human impacts are as sustainable as the energy it produces.
Power – The rate at which energy is transferred or converted. – The power generated by the wind turbines was sufficient to supply electricity to the entire village.
Plant – An industrial site, usually consisting of buildings and machinery, where goods are manufactured or energy is produced. – The nuclear power plant provides a significant portion of the region’s electricity needs.
Hydroelectric – Relating to the generation of electricity using flowing water to drive a turbine. – The hydroelectric dam harnesses the river’s flow to produce renewable energy.
Energy – The capacity to do work, such as causing motion or generating electricity. – Solar panels convert sunlight into energy that can be used to power homes and businesses.
Water – A transparent, tasteless, odorless, and nearly colorless chemical substance, essential for most forms of life and used in various industrial processes. – The water from the reservoir is used to cool the machinery in the power plant.
Dam – A barrier constructed to hold back water and raise its level, forming a reservoir used to generate electricity or as a water supply. – The construction of the dam has significantly increased the region’s capacity for hydroelectric power generation.
Turbines – Machines for producing continuous power in which a wheel or rotor is made to revolve by a fast-moving flow of water, steam, gas, or air. – The turbines in the wind farm convert kinetic energy from the wind into electrical energy.
Flooding – The overflow of water onto land that is normally dry, often caused by heavy rain or dam failure. – The engineers designed the dam to minimize the risk of flooding in the downstream areas.
Navigation – The process or activity of accurately ascertaining one’s position and planning and following a route, often used in the context of waterways. – The river’s navigation channels were improved to facilitate the transport of goods by barge.
Sustainability – The ability to maintain ecological and resource balance over the long term without depleting natural resources. – The city implemented sustainability practices to reduce its carbon footprint and promote renewable energy sources.
