How is electricity generated in a hydroelectric power station?

Electricity in a hydroelectric power station is generated by converting the energy of falling or flowing water into electrical energy.

In a hydroelectric power station, the process of electricity generation begins with the collection of water in a high-altitude reservoir. This water is then allowed to flow downhill and gain kinetic energy due to gravity. The flowing water is channelled through pipes, known as penstocks, towards a turbine. The kinetic energy of the water turns the turbine, which is connected to a generator.

The generator is the heart of the power station. It consists of a rotor (the moving part) and a stator (the stationary part). The rotor is fitted with powerful magnets and the stator is wound with thousands of turns of conducting wire. As the turbine turns the rotor, the magnets move past the conducting wire. This movement of magnets relative to the wire induces an electric current in the wire due to Faraday's law of electromagnetic induction. This is the same principle used in other types of power stations, such as nuclear or coal-fired stations, but the energy source turning the turbine is different.

The amount of electricity generated depends on two factors: the volume of water flowing per second (the flow rate) and the height from which the water falls (the head). The greater the flow rate and the head, the more kinetic energy the water will have and the more electricity can be generated.

Once the electricity is generated, it is sent through transformers to increase its voltage. This is because electricity can be transmitted more efficiently at high voltages. The electricity is then sent along power lines to homes, businesses, and industries.

Hydroelectric power is a renewable source of energy as it uses the Earth's water cycle to generate electricity. It is also a clean source of energy as it does not produce harmful emissions or waste products. However, the construction of large hydroelectric power stations can have significant environmental impacts, including changes to ecosystems and displacement of local communities.