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Hydroelectric Power

  • Last Updated : 03 Sep, 2021

A source of energy can consistently provide enough usable energy over a lengthy period of time.

A good energy source should be:

  • Easy transportation: coal, petrol, diesel, and LPG, for example, must be transported from the point of production to the point of consumption.
  • Convenient and safe to use: nuclear energy, for example, can only be utilized by highly qualified engineers with the aid of nuclear power plants, making it both safe and convenient to use.
  • Easy storage: large storage tanks are necessary to store gasoline, fuel, and LPG, for example.

Source of energy are divided into two groups:

  • Conventional sources of energy: These are widely utilized and provide a significant percentage of our energy needs.
  • Non-conventional sources of energy: These are not as widely used as conventional energy sources and only satisfy a portion of our energy needs.


The term “hydroelectricity” refers to the use of water to generate electricity.

It is a non-conventional source of energy. The gravitational force of falling water is the major source of hydropower in this area. There is no water used in the energy generation process. It is the most commonly utilized renewable energy source, accounting for 3% of total global energy consumption. Hydroelectricity has a cheap cost of production, providing it with a competitive advantage as a source of energy. A big hydropower plant’s average electricity cost is relatively low. 

Hydropower plants have the benefit of being flexible since their energy output is based on the amount of water released. Because this can be regulated, hydropower plants have the advantage of being flexible. The output may be adjusted to meet the needs of the situation.

Hydroelectric Energy

Kinetic energy is present in flowing water. Water-wheels are rotated and water-mills are driven by the energy of flowing water to crush wheat into flour. The traditional usage of flowing water’s energy has been changed by technological advancements and is now utilized to create electricity. The energy of falling water is captured in hydro-power facilities using a water turbine and then used to drive generators.

Hydro Power Plant

The term “hydro-power plant” refers to a power plant that generates electricity by rotating a turbine (which powers the generator) using flowing water (or hydroelectric power plant).

Hydro Power Plant

Working of Hydro Power Plant

Hydroelectricity is the electricity generated by utilizing the energy of falling (or flowing) water. The hydroelectric plant, in turn, necessitates the construction of a dam.

This dam is built on a water source, preferably a river. Because the dam is a huge wall that stops the river’s flow, a lot of water gathers behind it. The water is fed into the dam by an inlet at the bottom of the dam. This intake leads to a descent down the dam’s penstock.

A turbine is utilized to extract energy from the falling water here. Turbines are also used in thermal power plants, although there are some significant distinctions between steam turbines and hydro turbines. A shaft connects the turbine to the generator. Electrical energy is created when the water turns the turbine.

Pumped storage is a feature of hydropower facilities that allows water to be stored as a reserve for times when electricity demand is highest. This is the hydroelectric equivalent of a battery charge. The dam utilizes a pump to push the water back up to the reservoir behind it when the power demand is low, such as at midnight. This water is then utilized during periods of high electricity demand.

A hydroelectric dam can adapt swiftly to variations in energy demand as long as there is enough water in the reservoir. The quantity of water flowing through the penstock, which affects the amount of power generated by the dam, is directly controlled by opening and closing the intakes.

The dam’s power building, which also contains a transformer, houses the turbine and generator. The transformer transforms the generator’s electrical energy into a high voltage. High voltages are used by the national grid to effectively transport electricity through power lines to the houses and businesses that require it. Other transformers decrease the voltage to a level that may be used.

Advantages of using Hydroelectric Power Plant

  1. Electricity generated by hydroelectric power plants does not pollute the environment.
  2. It is a fairly reliable source of energy. Unless a different output is needed, there are relatively few variations in the electric power produced by the facilities.
  3. It is a renewable source of electricity since the water in the dams fills up on its own owing to rain.
  4. Hydroelectricity is significantly safer than fossil fuels and nuclear energy, for example. There is no need for gasoline.
  5. Dams are used to control floods and provide irrigation.

Disadvantages of using Hydroelectric Power Plant

  1. Power plants are expensive to construct in general. Hydroelectric generating stations aren’t exempt from this rule.
  2. Dams can only be built in a limited number of locations, such as mountainous terrains.
  3. The plant that is immersed underwater rots under anaerobic circumstances, resulting in massive volumes of methane production. Methane is a greenhouse gas that contributes to global warming.
  4. The amount of water available has a direct impact on electricity generation and energy pricing. A drought might have an impact on this.
  5. People residing in the vicinity of the dams have a challenge of adequate relocation.
  6. Vast areas of agricultural and human land have been flooded.
  7. The fish in the region downstream of the dam does not obtain enough nutrients as a result of the dam’s construction, and their production declines.

Sample Problems

Problem 1: What are the various hydropower plant types?


There are mainly three types of hydropower plant:

1. Cascaded/Succession power plant: It generates electricity through a series of canals.

2. Pumped Storage: This method of pumped storage uses the flow of water from a reservoir in the higher reservoir to a reservoir in the lower reservoir.

3. Tidal Power Plants: Tidal power plants use tides to generate electricity.

Problem 2: What type of energy transformation occurs in a hydroelectric power plant?


There are three different transformations available.

  • To begin, potential energy (due to the height of the water in the reservoir) is converted to kinetic energy (the energy derived from a large height falling of water).
  • In the turbine, the kinetic energy of the water is transformed into mechanical energy.
  • The turbine is connected to the generator. This energy is converted into electrical energy by a generator.

Problem 3: Explain the working of a hydroelectric power plant to produce electricity.


To generate hydroelectricity, high-rise dams are built on rivers to impede the flow of water and collect it in extremely huge reservoirs. The water from the dam’s high level flows through pipes to the turbine at the dam’s bottom. The generator is linked to the turbines.

The generator generates energy by rotating the turbines. When water is held at a high elevation in a dam, it has a lot of potential energy, which is transformed into kinetic energy of flowing water, which is then converted into mechanical energy of the turbine, which is then converted into electric energy by the generator.

Problem 4: Justify hydropower as a renewable energy source in one sentence.


Water is used in hydropower plants, and water may be replenished by nature with little effort. As a result, hydropower is a renewable energy source.

Problem 5: What are the major disadvantages of hydropower plants?


Major disadvantages of hydropower plants are:

  • Highly expensive
  • Large areas of human habitation and agricultural fields are submerged.
  • Dams can be made in limited areas.
  • People residing in the vicinity of the dams have a challenge of adequate relocation.
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