Writing Task 1
The diagram shows how electricity is generated by a hydroelectric dam.
Sample Answer 1
The diagram illustrates the production of power through the use of a hydroelectric dam.
The process begins with water in a reservoir and ends with the transmission of power via long-distance power lines.
In order to generate hydroelectricity, the first step is to collect water in a reservoir. When power generations begins the water passes through an intake in the bottom of the dam and then enters a long tunnel called a penstock. On the other hand, when power is not being produced the intake is blocked by a large gate that prevents the flow of water. However, when the intake is opened, the water flows down the penstock and the pressure it creates is used to spin a turbine, which is connected to a generator in a place referred to as the powerhouse. At the same time, the water that has gone through the turbine flows out into the river below the dam. Finally, the generator in the powerhouse is connected to power lines which are used to transport the electricity over long distances.
(175 words)
Sample Answer 2
The diagram illustrates the production of power through the use of a hydroelectric dam.
Overall, the process is a rather complicated one, beginning with water being accumulated in a reservoir and ending with the transmission of power into the power grid via long-distance power lines.
Accumulating water in a reservoir is the first stage in generating hydroelectricity. When power generation occurs, water enters a lengthy tunnel known as a penstock after passing through an intake at the base of the dam. The intake is blocked by a massive gate that stops the flow of water whilst power is not being produced. The water runs down the penstock when the intake is opened, and the pressure it generates is utilised to spin a turbine that is connected to a generator in a location known as the powerhouse. The water that has passed through the turbine simultaneously empties into the river below the dam. Ultimately, the generators in the powerhouse are linked to transmission lines, which are used to transfer electrical energy over long distances.
(173 words)
