The diagram illustrates the process of generation of electricity by a hydroelectric dam
Overall, the process is a rather complicated one, beginning with water in a reservoir and ending with the transmission of power via long-distance power lines
At the first step, water trapped in the reservoir behind the dam passes through an intake. It then flows into a long tunnel called a penstock. On the other hand, the intake is blocked by a large gate that prevents the flow of water while power is not being produced
After opening the intake, the water flows down the penstock, and the pressure it generates is used to spin a turbine, which is connected to a generator in the powerhouse above. At the same time, the water that has gone through the turbine flows out into a river below the dam. Eventually, the generator in the powerhouse is connected to power lines which are used to transfer electrical energy over long distances to where it can be used