The diagram illustrates the process of electricity generation in a hydroelectric power station. Overall, there are 4 main stages of this cyclical process, and the main steps are storing water, managing water flow, and the operation of turbines and generators.
The process starts with channelling water from the river to get it stored in the high-level reservoir behind the dam. During the day, the dam is opened to flow the stored water from the high-level reservoir to reversible turbines. Simultaneously, these turbines operate generators to produce electricity and transmit it to the national grid via power lines.
After passing the electricity the water is pumped into the low-level reservoir through turbines. During the night, the process reverses, and the reversible turbines retrieve the water from the low-level reservoir. This water is transported back to the high-level reservoir, making it available for the next cycle of electricity generation.