Water has huge power. We can feel this on our bodies when we cross a sea or river. The power we get from water is called hydropower. Hydropower has been one of the first forces used by human beings to simplify their work. For example, tasks such as turning wheat into flour, processing wood to make paper, making textile, and turning hard metals into various interesting shapes, which were difficult to do earlier, have been made easy by using hydropower.
Dams are made by erecting huge walls in water to generate electricity. Even today there are ferries and boats without engines that use the force of flowing water. Even tides in the oceans can be used to produce energy.
How does watermill work?
A watermill uses a large wooden or metal wheel to generate power. It consists of many small blades, over which the flowing water of a stream runs; this wheel is called the ‘water wheel’. The flowing water rotates the wheel. This rotational movement produces electricity when connected to a generator.
Although mills were used to generate hydropower in earlier times in all countries, people in the underdeveloped countries use them even today. Electricity produced in such a manner is pollution free and does not harm our environment.
How is electricity generated by using a dam?
Dam walls are mostly made of a material called concrete. These dams retain a large amount of water. The retained water puts very high pressure on the lowermost layers of water. If the water in these lowermost layers is diverted, it flows at a very high speed, and hence a high energy is produced with the help of a device called turbine. In the turbine, the energy is used to generate electricity.
The type of energy we can reuse since it is unlimited in nature is called renewable energy, such as the energy from the sun, wind, and water. Hydropower is currently the only renewable energy that is used to a large extent. In Austria, approximately half of the electricity is generated by hydropower, while in Norway all the electricity is generated by hydropower.
How is energy obtained from high and low tides?
High and low tides come alternately, that is, one after the other. In high tides, the level of water rises and covers a part of the coast, and in low tides it flows away again. This energy of the tides is used to run turbines. Special water turbines are used in tidal power plants. Water – rising in case of high tides and receding in case of low tides – can flow through these turbines in both the directions.
Electricity is generated in tidal power plants due to the rotary movement of the turbines.These power plants need a tidal hub – the difference in the height of water between high and low tides – of more than 5 m to be able to work economically. Such a power plant is in the French Bretagne, in St. Malo. Here, the tidal hub is at 12-15 m
How does a ferry work without an engine?
Ferries without engines are driven by the flow of water. They are attached to a wire cable, which is spanned across the river by means of two short ropes. When the ferryman shortens one of the two short ropes with the help of a device called ‘winch’, the ferry is tilted at an angle to the current, and the force of the current propels the ferry across the river.
Did you know that…
Water wheels were used as early as 3500 years ago in Mesopotamia (which is now Iraq) to pull water up?
Many valleys were flooded for the largest dam in China called the Three Gorges Dam? Millions of people who lived in these valleys had to leave their homes.
Hydropower plants produce about 20% of the world’s electricity and supply more than 1 billion people with power?
Lake Como in Italy is the deepest lake in Europe, in the foothills of the Alps?
The tidal hub in the Mediterranean sea is much smaller than at the coast of the North Sea?
Featured image credit: pixabay