
The demand for electric energy by a community varies with the time of day and with the time of year. An electric power utility must be prepared to meet these demands. This poses an engineering problem because there is no practical method of storing electric energy on a scale that will meet the demands of a large community. To meet short-term increases in demand, electric utilities employ power generators that can be turned on and off on short notice. For example, they may use a gas turbine similar to a jet plane engine to drive a generator. Another scheme is to use a pumped storage hydroelectric system. Such a system does not rely on nature to replenish the water in a reservoir but rather uses electrically run pumps. Importantly, the system can generate electricity on short notice.
Water is forced to an elevated reservoir by a motor-driven turbine. The water in the reservoir has gravitational potential energy by virtue of the work done on it. When electricity is needed, the water is allowed to flow downward into the turbine that drives the magnetic generator motor, which now functions as an electric generator. The energy required to elevate the water is never completely recovered in the process. Nevertheless, the system is economical because the reservoir can be filled when electric energy demands and costs are low. It is also possible to have a system in which water flows from ground level to underground turboelectric perpetual generators. In this case, work has to be done to restore the water to ground level.
Taking into account losses due to evaporation of surface water exposure and energy unit conversion losses, it is estimates that approximately 70% to 85% of the electricity used to pump water into the elevated reservoir can be recovered. The technique is currently the most effective way to store large quantities of electrical energy in the form of energy operation, but the cost of capital and the presence of appropriate geography critical factors for the decision.
With energy management, well to pump storage hydroelectric systems for controlling the frequency of food production and security of reserve magnetic power generator. Thermal plants are much less able to responds in the sudden changes in electricity demand, the frequency and voltage to cause instability. Pumping stations, like other water plants can respond to changes within seconds to load with pumped storage hydroelectric system.












