What is a hydroelectricity project?

Suppose you set up a small wheel in a flowing river. The river’s flow will turn the wheel on its own. Now, suppose we connect this wheel to a motor that uses the energy produced by the wheel and generates electricity from it?

That, in the simplest form, is a hydro-electric project.

A hydro electric project generates power from running water. It can be created on waterfalls or flowing rivers. The spinning wheel rotates because of the flow of the water. This spinning wheel is attached to a turbine(a system to produce electricity) that generates electricity. This electricity is then supplied to the national grid, from where it reaches homes, fields, and other users.

But, sometimes, especially in summer, the flow of the river tends to be low. The demand for electricity is high. How does the power plant manage that?

There are two types of hydroelectric projects. Smaller hydroelectric projects are based on simple flow. They are typically less than 30 MW (MegaWatt) power generation.

Larger projects, on the other hand, start by building a dam and a reservoir. A reservoir is a large storage tank for water. The dam takes water from the river and stores it in the reservoirs. Then, when the flow of water is less, the water is released from the reservoir. This helps both the hydel power projects, and the fields that depend on river water for irrigation, etc.

Are hydel power projects bad for the environment?

Once a hydel power project has been made, there is no wastage at all, because only the flow of the water is used to generate electricity. This makes them among the cleanest power generation methods.

However, a dam and generation system leads to the creation of large reservoirs. Since these projects are typically made in the mountains to benefit from the natural downward flow of water, this leads to the creation of areas in the mountains where a large quantity of water is stored. Usually, mountains do not store that much weight. This can lead to situations like landslides.

When we divert the water of the river to the dam and reservoir or run it through a turbine, it does affect the fish and other creatures that live in the water. It also affects the migratory species like birds, that depend on seasonal variations in the river flow.

Another environmental impact of hydel power projects is that their construction takes a long time. A hydel project can take up to 2-3 years to be made. During this time, the pollution associated with construction – diesel from the trucks ferrying material, diesel generators to keep machines going, electricity for the construction site, and fine dust from grinding the mountain rocks – all this is present in the area.

The quality of water that flows into a reservoir is different from the quality of water that flows out of the reservoir. Stored water is different from naturally free flowing water that is fresh from the glaciers.

These are some of the environmental effects of hydel power projects.

Can I make a hydel power project to run on the running tap water in my house?

Yes, you can! Do try making a simple hydel power project at home and then try to answer these questions:

A. Can we make a running flow project more efficient by using a narrow channel to increase the flow of water?

B. Slower spinning of the wheel leads to less electricity. Is there a point at which the wheel turns so slowly that it produces no electricity at all?

Do write your answers with your name in the comments below.