Evolution and Development of Pumped Storage

The unique functional value of the pumped storage power station makes it an important part of the power system of most countries. my country’s energy structure adjustment and power system development require pumped storage power stations of a certain scale. Therefore, pumped storage power stations are of great significance for energy transformation and the construction of new power systems.

The role of pumped storage power plants

Both peak shaving and valley filling

The pumped storage power station is a special form of hydropower station. During the peak load period of the power system, it can be used as a hydropower station to generate electricity and participate in peak regulation; during the low load period, it can also be used as a pumping station to absorb low-cost low-cost electricity and pump storage to adjust power. The peak-to-valley difference of the system can improve the daily load characteristics of the power system and the operating conditions of large-scale thermal power and nuclear power units. At the same time, it can also reduce power generation costs, improve environmental pollution and reduce thermal power environmental protection expenses. Therefore, the peak-shaving economic benefit of pumped storage power station instead of thermal power unit is significant.

emergency power supply

Pumped-storage power station units start and stop quickly. It usually takes only 2 to 3 minutes from start-up to full-load power generation, and even faster when unloading. It only takes about 3 minutes. Because power system accidents are usually sudden, in order to ensure the safety of the power grid and the needs of users, emergency reserve capacity must be invested in time. The pumped storage power station is the best solution to undertake emergency backup tasks in the power system, and is an ideal emergency backup security power supply.

Take on temporary tasks

The pumped storage unit has a fast starting speed and a high success rate, and is capable of performing temporary tasks such as some coal-fired power units shutting down and failing to start on time, requiring temporary replacement of the unit. At the same time, since the pumped storage unit can be used as both a power source and a load, the pumped storage unit can cooperate closely during the load shedding and full-load vibration tests during the trial operation of high-power nuclear power, water, and thermal power units, which makes the grid dispatch more efficient. Convenient and simple.

Realize frequency modulation and phase modulation

The characteristic of electric power production is that production, supply, and sales are completed at one time. If the supply exceeds demand, the cycle will rise, and vice versa. The national standard cycle is 50Hz, and the allowable variation range is 49.8-50.2Hz, otherwise the power supply quality is unqualified. Due to the flexible use of pumped storage units, strong climbing ability, fast output and rise and fall speeds, and the ability to quickly track grid load changes, it has the ability to undertake grid frequency modulation tasks and is the most ideal frequency modulation power station in the power system. At the same time, not only the active power but also the reactive power need to be balanced in the power system, so as to keep the grid voltage stable, otherwise the quality of power supply is difficult to guarantee, so some units in the power system are required to undertake the task of phase modulation. The phase modulation of the pumped storage unit consumes less power and is easy to control. It is the best solution for the phase modulation task in the power system.

A brief introduction to the development of pumped storage

The pumped storage hydropower station was born in Switzerland in 1882, and its main purpose was to store water in the early days. In the first half of the 20th century, the development of pumped storage power stations was slow. Until the end of World War II in 1945, only more than 50 pumped storage power stations were put into operation in the world, mainly distributed in the United States, Japan and some European countries.

From the 1960s to the 1980s, it was a period of vigorous development of pumped storage power stations, especially from the 1970s to the 1980s, ushered in the golden period for the development of pumped storage power stations. After World War II, European and American countries have experienced 20 years of rapid economic development, the power load has increased accordingly, and the living standards of the public have improved, resulting in a rapid increase in the difference between peak and valley power consumption. Pumped storage power stations with good peak-shaving and valley-filling performance ushered Opportunities for rapid development. In the 1960s, the installed capacity of pumped storage power stations increased by an average of 1,259MW per year, while in the 1970s and 1980s, they increased by 3,051MW and 4,036MW respectively.

After the 1990s, the growth rate of the world economy dropped sharply. The economic slowdown led to a slowdown in the growth of electric power load. The average annual growth rate of pumped storage power station construction dropped from 6.45% in the 1980s to 1.55%.

According to the latest data from the “White Paper on Energy Storage Industry Research 2023”, the cumulative scale of global power storage in operation in 2022 will be 237.2GW, with an annual growth rate of 15%; the proportion of cumulative installed capacity of pumped storage will be lower than 80% for the first time, a year-on-year decrease of 6.8% %.

my country’s pumped storage power station started relatively late. In the 1960s, a reversible diagonal flow unit with a single unit capacity of 11,000 kW imported from Japan was installed in the Gangnan Hydropower Station in Hebei Province, and two domestically produced units were installed in the Miyun Hydropower Station in Beijing. The single-unit capacity is 11,000 kW reversible oblique flow units, making the Gangnan and Miyun hydropower stations a hybrid power station, which can not only generate electricity conventionally, but also pump water for energy storage.

In recent years, with the transformation of energy to green and low-carbon, the scale of my country’s pumped storage power station industry is constantly expanding, and the industrial chain system has basically formed. According to the data of the National Energy Administration, in 2022, China’s newly installed pumped storage capacity will reach 8.8GW. By the end of 2022, the cumulative installed capacity of pumped storage will reach 45.19GW, an increase of 24.18% compared with 2021, accounting for 25% of the total global market. The rate is 38%.

In 2021, the National Energy Administration issued the “Pumped Storage Medium and Long-Term Development Plan (2021-2035)” to guide the construction of pumped storage power stations to further accelerate the policy. It is estimated that the installed capacity will reach 62GW by 2025 and about 120GW by 2030 . As a kind of energy conversion technology, pumped storage power station can improve the grid structure and improve the safety performance of the grid, and has been highly valued by the state.

Positioning problem of pumped storage

The evaluation of pumped storage power plants is usually based on the grid price. This relatively one-sided view leads to a lack of understanding of the functional positioning of pumped storage power plants in the power system. The pumped storage power station is formed by not distinguishing the functional differences between the pumped storage power station and the conventional power plant in the system, only seeing its short-term shortcomings, ignoring the system economy, and its important role in the safe and stable operation of the power system and the quality assurance of power supply. The inertial awareness of high on-grid electricity prices and poor economic efficiency has seriously affected the correct evaluation of pumped storage power plants.

The pumped storage power station is mainly based on dynamic benefits in the power grid, and the on-grid electricity price only reflects the amount of power generated by the pumped storage power station, which is relatively low compared with conventional hydropower stations, about a quarter of the power generated by conventional hydropower stations; and The power generation of pumped storage power plants is often closely related to the grid load level, power source structure and regional economic development, so it is difficult to determine. The low power generation of pumped storage power stations is the inevitable result of system optimization. If only the on-grid electricity price is used as the only indicator to locate pumped storage projects, it will have a great negative effect on the project approval of the power station, which is extremely unfavorable to the current power structure adjustment; and For the power grid, more attention is paid to providing power with more power and so on. The emergence of a series of problems makes the benefits of the pumped storage power station not fully presented, which indirectly affects the enthusiasm for the construction of the pumped storage power station.

The development idea of pumped storage

Coordination and integration with power planning

The planning of pumped storage should be under the guidance of the development planning of the electric power industry, and should be planned in a unified manner with other power sources and power grids, so as to effectively play the active role of power stations in ensuring the safety and stability of the power grid, improving the operating efficiency of the system, and realizing the optimal allocation of resources in the largest range.

Highly adaptable to energy strategy

The pumped storage planning must adapt to the overall national energy development strategy, adapt to the current energy structure adjustment, green, low-carbon and clean development situation, and meet the new requirements for the safe operation of the power system and the development of new energy for the construction of pumped storage power stations.

Strengthen the unified planning of power stations

The construction of a pumped storage power station must combine the power structure, power layout, power grid development, load characteristics, and national networking and other related factors, as well as the reasonable positioning of the functions of the pumped storage power station at the sending and receiving end, to determine the reasonable proportion, layout and construction of the pumped storage power station Timing, so that the construction and development of pumped storage power plants proceed in a scientific and orderly manner.

Taking into account the comprehensive benefits of diversification

In the process of promoting the construction of pumped storage power stations, the survey and site selection of power station resources should be done well to ensure that the scale of pumped storage power stations is suitable, the conditions are good, the indicators are good, and the impact on the natural and ecological environment is small. On this basis, pumped storage Comprehensive benefits of energy, drafting detailed construction plans, etc.

Accelerate the preliminary work of the power station

According to the principles of proximity to the load center, superior terrain and geological conditions and technical indicators, comprehensively and systematically carry out site selection for pumped storage power stations, improve the progress of preliminary work, prepare project reserves in advance, and ensure the implementation of pumped storage construction plans.

Strive for a reasonable return on investment

At present, the construction and operation costs of pumped storage power stations in my country are basically borne by power grid companies, which substantially increases the operating pressure of power grid companies. In the future, reasonable calculation of the investment and operating costs of pumped storage power stations will be considered, and efforts will be made to fully include them in the grid operating costs, and a scientific and complete related electricity price mechanism will be established.

To sum up, with the continuous development of my country’s pumped storage industry and the active orientation of national policies, pumped storage power stations will be given more responsibilities and missions. In the foreseeable future, my country will usher in a golden age for the pumped storage industry .