Model Answer

The given diagram illustrates the process of electricity production at a hydroelectric power station.

Overall, water is the main source of power production that moves the turbines to operate the generator that produces electricity in the power station. Water is reused to produce electricity. The power station works day and night.

In the day, the river water accumulates in the high-level reservoir created by the dam. The intake opens during the day and allows water to flow to generate electricity. The flowing water reaches the turbines and rotates them. The generator produces electricity while operated by the turbines. Generated electricity transfers to the national grid through power lines.

After rotating the turbines, water moves to the low-level reservoir. But during the night, the turbines work in reversible order and pump water back to the high-level reservoir. Water goes in the opposite direction during the night. The intake, which is open during the day, is closed at night. It does not allow water to move towards the turbine. Water pumped back by the turbines is again stored at the high-level reservoir and reused to produce electricity during the day.