How does pumped storage work？

Pumped storage power station is an important energy storage mode, which is widely used in modern power system, especially in regulating power grid load and improving energy utilization efficiency. It converts electric energy into water potential energy for storage, and then converts the potential energy into electric energy for release when necessary, thus realizing the "time transfer" of electric energy. This technology not only improves the stability of the power grid, but also provides strong support for the large-scale access of renewable energy.

The basic structure of pumped storage power station usually includes main equipment such as upper reservoir, lower reservoir, pump turbine and generator motor. Its operation principle can be divided into two stages: pumping stage and power generation stage.

When the power consumption is low (for example, at night), the power demand in the power grid is low, and the electricity price is low and the system power is sufficient. The pumped storage power station will use these surplus electric energy to drive the motor and drive the water pump to pump the water from the lower reservoir to the upper reservoir for storage. This process is actually to convert electric energy into water potential energy and store it, which is equivalent to "charging" the power grid.

At the peak of electricity consumption (such as day or evening), when the demand for electricity increases sharply and it is difficult for traditional power stations to meet the load changes quickly, pumped storage power stations will release the previously stored energy. At this time, the water in the upper reservoir is released, flows through the turbine and drives the generator to generate electricity, and then converts the potential energy of water into electric energy and feeds it back to the power grid. This process is similar to conventional hydropower generation.

Pumped storage power station has the advantages of fast response, flexible start and stop, long service life and environmental friendliness. Compared with traditional thermal power generation, it does not rely on fossil fuels and produces almost no pollutant emissions; Compared with battery energy storage, although the energy conversion efficiency is slightly lower (generally between 70% and 85%), it has mature technology, low cost, large capacity and long service life.

In addition, with the rapid development of intermittent renewable energy such as wind energy and solar energy, pumped storage has become an ideal choice to balance power supply and demand and smooth power supply fluctuation. It can effectively alleviate the instability of renewable energy generation and improve the acceptance of clean energy in power grid.

In a word, pumped storage, as a mature energy storage technology, is being widely used around the world. It not only helps to improve the flexibility and reliability of the power system, but also provides an important support for achieving the goals of peak carbon dioxide emissions and carbon neutrality. In the future, with the further optimization of energy structure and the development of smart grid, pumped storage power stations will play a more important role in energy transformation.