Pumped storage

Pumped storage power station is a special form of hydroelectric power generation system.The system integrates pumping and power generation facilities. Reservoirs are set up in the upstream and downstream. In the period of low power load or high water, the remaining energy provided by other power stations is used to pump water from the lower reservoir to the upper reservoir with high terrain to convert electric energy into potential energy; in the daytime load peak period or dry season, the water in the upper reservoir is released to drive the hydro-generator unit to generate electricity, and the potential energy is converted into electrical energy.

Pumped storage technology is currently the most mature and widely used large-scale energy storage technology. It has the advantages of large capacity, long life (economic life of about 50 years), and low operating costs. It can provide services such as peak shaving, valley filling, frequency modulation, and accident backup for the power grid. Its good regulation performance and rapid load change response capability are of great significance for effectively reducing the instability caused by new energy generation input into the power grid.

However, the construction of pumped-storage power stations is also subject to certain conditions. For example, the site selection requires topographical conditions with small horizontal distances, large height differences between upper and lower reservoirs, geological conditions with high rock strength, good seepage resistance, and sufficient water sources to ensure water demand for power generation. In addition, it is necessary to consider a series of environmental protection issues such as the inundation of the upper and lower reservoirs, changes in water quality, and soil salinization in the reservoir area.

From the 1950s to the 1980s, developed countries represented by the United States, Japan, and Western European countries drove the large-scale development of pumped storage power stations. However, from the 1990s to the present, with the exception of Japan, the United States and Western European countries have slowed down the development of pumped storage. For our country, the development of pumped storage has the following characteristics:

(1) China’s pumped storage power plants have developed rapidly in the past 20 years. As of the end of 2010, the installed capacity put into production reached 16,345MW, ranking third in the world; the installed capacity under construction reached 12,040MW, ranking first in the world. Even so, the installed capacity of pumped storage power plants accounts for a relatively low proportion of my country’s total installed capacity.

(2) The construction technology has reached the world’s advanced level. Large-scale electromechanical equipment originally relied on imports, but after the introduction, digestion and absorption of technology in recent years, it has basically possessed production capacity.

(3) In accordance with the current national policy, the hydro-storage power station shall, in principle, be constructed and managed by power grid companies.

During the “Twelfth Five-Year Plan” period, the government attaches great importance to the development of hydropower. According to relevant data from the China Electricity Council (CEC), the planned goal of pumped storage is to reach 41,000MW by 2015 and 60,000MW by 2020. This means that in the next ten years, the new installed capacity of pumped storage will exceed 40,000 MW, and China’s pumped storage is experiencing a new round of development climax.