IELTS Task 1: Process diagram: Generating electricity

The diagram shows how electricity is generated by a hydroelectric dam

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The diagrams illustrates the way in which a hydroelectric dam creates electricity.

Overall, it is apparent that water, which is contained in the reservoir, is the key material for the process. Meanwhile, electricity is generated in the powerhouse.

Initially, water flows through an intake to a chamber called penstock. After that, water follows the current and applies pressure to the turbine, forcing it to rotate in a circular movement. At the next stage, the turbine begins to creates energy. Energy is then supplied to the generator attached to the turbine. Following this, the generator converts energy into electricity in the powerhouse, and power lines are in charge of distributing electricity to distant areas through a machine.

It is interesting to note that the dam is constructed on the river, and the bulk of the procedure happens underground. Besides, abundant water follows its current and ends up in the river. Then, it is renewable, and electricity is automatically generated again with the hydroelectric dam.

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There are only a few things I'd like to point out in your essay.
The diagram illustrates
Furthermore, I don't think water is a material, just look it up in Cambridge Dictionary the definition :"a type of physical thing, such as wood, stone, or plastic, having qualities that allow it to be used to make other things" . Therefore, you should replace it by " substance" or "source"

Otherwise, I think everything is very good. Good job !

It is good for you to use word "Initially, After that, At the next stage, and Following" to describe stages. Good Job!

For introduction, you should make it longer
The diagrams illustrates
Water is not the key material -> Water is the key substance.
The turbine begins to creates energy
Good job!

Thank you all of you for helping me!