What is Hydroelectric Power Plant? How Does It Work?

What is Hydroelectric Power Plant? How Does It Work?

The function and varieties of hydroelectric power plants: from water to renewable energy.

A water body that is elevated above a river channel has potential energy, which is converted to kinetic energy and then, at the river channel’s lowest point, to electrical energy to generate hydroelectric power.

We will discuss the definition and types of hydroelectric power plants in this article. Please keep reading. Here are the Advantages and Disadvantages of Hydroelectric Power Plants.

What is Hydroelectric Power Plant?

In order to convert the potential energy of water into electrical energy, a hydroelectric power plant consists of a number of structures and electromechanical devices that can run continuously. The flow rate and elevation drop both affect the amount of electrical energy that is readily available.

A hydroelectric power plant has the following parts:

  • A dam or weir holds back river water, creating a reservoir and a drop of water that can be used to generate energy. Dams can be made of concrete or earth, with the latter being the more popular option.
  • Spillways: These allow some of the water that has been accumulated to be released without going through the turbines; the water can then be used for irrigation. They can be at the top or bottom of the dam’s main wall and are there for aesthetic purposes only. To avoid scour damage caused by the falling water, the majority of the water is directed into a plunge pool at the dam’s toe.
What is Hydroelectric Power Plant? How Does It Work?
  • Water intakes: through a penstock, they draw in the ponded water for the turbines. Water intakes have gates to limit the amount of water that gets to the turbines and grids to filter out any debris, such as tree trunks and branches, etc.
  • Powerhouse: It houses the hydraulic and electrical machinery (turbines, generators, and transformers), as well as the service area with control and testing rooms. The equipment area can be kept dry during maintenance or equipment disassembly thanks to the inlet and outlet gates.
  • The rotating shaft of a turbine is powered by the water that passes through it. Pelton, Francis, and Kaplan turbines are the three main varieties of turbines (propeller type).
  • Transformers are electronic devices that can change the voltage in an alternating current circuit while keeping the power on.
  • Cables used to transmit electricity are called electrical power transmission lines.

You can learn more about other types of power plants, such as Nuclear Power Plants, Thermal Power PlantsGeothermal Power PlantsSolar Power PlantsWind Power PlantsTidal Power Plants, and Biomass Power Plants.

Types of Hydropower Plants

Impoundment, diversion, and pumped storage facilities are the three different types of hydropower facilities. Some hydropower plants rely on dams, while others do not. Hydropower plants can be small, suitable for a single house or village, or large, producing electricity for utilities.


An impoundment facility is the most prevalent kind of hydroelectric power plant. An impoundment facility uses a dam to store river water in a reservoir. These facilities are typically large hydropower systems.

When water from the reservoir is released, it passes through a turbine, spinning it and turning on a generator to create electricity.

The water may be released to address shifting energy requirements as well as other needs, including flood control, leisure activities, fish passage, and other environmental and water quality requirements.


What is Hydroelectric Power Plant? How Does It Work?

A diversion, sometimes called a “run-of-river” facility, channels a portion of a river through a canal and/or a penstock to utilize the natural decline of the river bed elevation to produce energy.

Using gates, valves, and turbines to control the water flow, a penstock is a closed conduit that directs water to turbines. The use of a dam may not be necessary for a diversion.

Pumped Storage

Pumped storage hydropower, also known as PSH, is another type of hydropower that functions like a large battery. The electricity produced by other power sources, such as solar, wind, and nuclear, can be stored at a PSH facility for later use.

Pumping water from one reservoir to another from one elevation to another is how these facilities store energy.

A PSH facility stores energy by pumping water from a lower reservoir to an upper reservoir when there is little need for electricity. When there is a high demand for electricity, the water is released back into the lower reservoir where it turns a turbine and produces electricity.

Sizes of Hydroelectric Power Plants

Hydropower facilities come in a variety of sizes, from large power plants that serve a large number of consumers to small, even “micro” plants that are run by private individuals for their own energy needs or to sell power to utilities.

  • Large Hydropower: Although definitions differ, the DOE defines large hydropower plants as those that have a capacity of more than 30 megawatts (MW).
  • The DOE defines small hydropower as projects that produce between 100 kilowatts and 10 MW, though definitions vary.
  • Micro Hydropower: A micro hydropower plant can produce up to 100 kilowatts of power. For a single house, farm, ranch, or village, a small or micro-hydroelectric power system can generate enough electricity.
What is Hydroelectric Power Plant? How Does It Work?

How Does the Hydroelectric Power Plant Work?

In general, the process involves a barrier – a dam or a crossbeam – that interrupts the water flow, creating a body of water that can be a reservoir or a hydroelectric basin.

Through adduction and diversion channels and tunnels, the water is conveyed into charge basins and is directed through penstocks toward hydroelectric turbines. Depending on the amount of energy needed, both flow regulation devices (distributors) and injection valves are used here.

The water enters a spillway where it is recycled back into the waterway after turning on the turbines and producing mechanical energy. A rotating electric generator (alternator) is directly connected to the turbine and turns the mechanical energy from the turbine into electrical energy.

This electricity has to be transformed in order to transmit it long distances: before being conveyed into transmission lines, the electrical energy passes through a transformer, which lowers the intensity of the current produced by the rotating electric generator, while raising its voltage.

The energy travels through a transformer once more before it is used, increasing the current’s strength and lowering the voltage to make it suitable for domestic, commercial, and industrial applications.

Read More: How Do Hydroelectric Power Plants Work?


A mature technology with tried-and-true solutions, hydropower has high reliability. Civil, mechanical, and electrical engineering are all used to build a hydropower plant.

Because hydropower plants can generate power to the grid immediately, they provide essential backup power during major electricity outages or disruptions. Flood control, irrigation support, and clean drinking water are additional advantages of hydropower beyond the production of electricity.

Leave a Reply

Your email address will not be published.