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IELTS 14 Academic Test 3 Task 1

The diagram illustrates the process of generating electricity using a hydroelectric power plant.

The overall system design is simple with relatively few components and primarily uses renewable energy provided by nature.

Firstly, potential energy is harnessed by damming a large body of water in a high-level reservoir that is fed by a river. A water pipe connects an outlet at the bottom of the dam to the power station’s turbine far below.

During the day, the dam’s outlet (referred to as the ‘intake’) is opened to allow water to cascade down the pipes and power the turbine, which drives the generator. The generator is connected to power lines that feed the national electricity grid. The spent water flows into a low-level reservoir.

At night, the intake is closed, while the turbine is powered by electricity to operate in reverse as a pump. Water is pumped from the low-level reservoir back up to the dam so that excess electrical energy from the grid can be stored as potential energy. This stored energy plus the potential energy of water added from the river will again be converted to electricity the following day.

(190 words)

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