Pumped storage power stations are equipped with dual purpose units for pumping and generating electricity, which can both pump water and generate electricity. During the day and in the first half of the night, the reservoir releases water, and the high water level passes through the dual purpose unit. At this time, the dual purpose unit serves as a generator, converting the mechanical energy of the high water level into electrical energy and transmitting it to the power grid. Addressing power shortages during peak electricity usage; In the latter half of the night, the power grid is in a low valley of electricity consumption, and electrical energy cannot be stored in the grid. At this time, the dual purpose unit is used as a water pump (the dual purpose unit can rotate in reverse), and the excess electrical energy in the grid is used to pump water from low water levels to high water levels and inject it into high water reservoirs. In this way, during the low valley of electricity consumption, the excess electrical energy in the grid is converted into mechanical energy for water storage in the reservoirs. At the peak of electricity consumption, the reservoir releases water and converts the mechanical energy of the water into electrical energy through a generator, which is then transmitted to the power grid. The water in the reservoir is used multiple times, together with two units, to complete multiple energy conversions. High water level reservoirs store a large amount of low water level water, which is equivalent to storing excess electrical energy in the power grid, solving the problem of electrical energy being unable to be stored. Due to the different electricity prices during peak and low periods, the peak electricity prices are high while the low electricity prices are low, which greatly improves the economic benefits of pumped storage stations.