Using pumped storage energy to create a new type of power system
- The installed capacity of electrochemical energy storage has been greatly improved, but pumped storage is still the main force
- Pumped storage has been widely used since the middle of the 20th century and has gradually become the most widely used energy storage technology in the world
With the proposal of the 2020 double-carbon target, when the strategic planning blueprint of "building a new type of power system with new energy as the main body" slowly unfolds, pumped storage has become the top priority for the realization of this huge planning system.
In 2023, Liu Hanyuan, deputy to the National People's Congress, vice chairman of the All-China Federation of Industry and Commerce and chairman of the Board of Directors of Tongwei Group, put forward relevant suggestions to promote the rapid development of China's pumped storage industry and help build new power systems.
Liu Hanyuan said that the operation mode of pumped-storage power stations is to convert energy between electric energy and water potential energy, use the surplus power of the power system to pump water to high places for storage, and discharge water for power generation when the power is insufficient. It has many functions, such as peak shaving and valley filling, frequency modulation, phase modulation, energy storage, emergency standby, and black start. It is the most mature energy storage technology with the lowest cost per kilowatt hour, and has long service life and high conversion efficiency With large installed capacity and long continuous discharge time, the energy conversion efficiency is about 75%.
After the completion of the project, the dam body of the power station can be used for about 100 years, and the service life of the motor equipment is about 50 years. At present, the cost of pumped storage per kilowatt hour is 0.21-0.25 yuan/kWh, which is far lower than other energy storage technologies. In terms of investment cost, the average hydropower station is about 9 yuan/W, the large pumped-storage power station is about 6.2 yuan/W, and the small and medium-sized pumped-storage power station (installed capacity is less than 50000 kW) is less than 5 yuan/W due to its low technical difficulty. By optimizing the design and adopting the small reservoir capacity scheme, the investment cost can also be significantly reduced to about 2 yuan/W, and the daily charging and discharging times can be reasonably increased. Under the existing technical conditions, the cost of pumped storage energy can be reduced to less than 0.1 yuan/kWh.
Pumped storage, as the earliest large-capacity energy storage technology, has been widely used since the middle of the 20th century and has gradually become the most widely used energy storage technology in the world. China's pumped-storage energy has been commercialized since the 1960s. After half a century of development, China's pumped-storage technology has reached the world-class level.
By the end of 2021, the cumulative installed capacity of global pumped storage energy reached 181GW, accounting for 86.2% of the total installed capacity of global energy storage; China's total installed capacity of energy storage is 46.1GW, of which 39.8GW is pumped energy storage, accounting for 86.3%, and 9.2% is electrochemical energy storage. In recent years, the installed capacity of electrochemical energy storage has been greatly improved, but pumped storage is still the absolute main force.
It is estimated that by 2025, the cumulative installed capacity of pumped storage may fall to 67%, but it is still more than twice that of electrochemical energy storage. Although the cost of electrochemical energy storage is continuously decreasing, it is expected that it will still be higher than that of pumped storage by 2030. Therefore, judging from the economy, the pumped storage is still the best choice to build a large-capacity long-term energy storage system.
Representative Liu Hanyuan believed that although China is the country with the largest installed capacity of pumped storage power in the world, the overall development speed has been slow in the past decade, and the construction speed has always been lower than expected. The construction scale during the "12th Five-Year Plan" and "13th Five-Year Plan" has not reached the planned goal, and the installed capacity of pumped storage power stations in China also has a large gap compared with developed countries.
According to the Medium and Long-term Development Plan for Pumped Storage Energy (2021-2035), the total scale of China's pumped storage energy production will reach more than 62GW by 2025 and about 120GW by 2030. If we want to accelerate China's realization of the "double carbon" goal and build a renewable energy-based, even 100% renewable power system, the current planning goal is far from enough.
According to the prediction of relevant institutions, in order to achieve the goal of carbon neutrality in China, according to the most conservative estimation, the installed capacity of pumped storage power stations needs to reach 130GW by 2025 and 250GW by 2030. Among them, Lihe pumped storage is the most important direction for the future development of pumped storage.
According to the research of the Australian National University, there are 616000 offshore pumped storage stations in the world, with a storage potential of about 23 million GWh. Only less than 1% of them can support 100% of the world's renewable energy power system. For China, Zhejiang Province, which accounts for only 1% of the land area, has about 3200 potential sites with 11000 GWh energy storage capacity, which is enough to support China to build a 100% renewable energy power system.
Based on this, in order to promote the rapid development of China's pumped storage industry and help build new power systems, the representative of Liu Hanyuan in 2023 has the following suggestions:
First, it is suggested to further carry out the survey of pumped storage stations and reserve advantageous resources. Select a number of reserve stations with good economic indicators and engineering construction conditions, and promote them to be included in the Medium and Long-term Development Plan for Pumped Storage Energy (2021-2035), laying a solid foundation for subsequent large-scale construction.
Second, it is suggested to strengthen the policy drive and focus on the large-scale construction of pumped storage projects during the "14th Five-Year Plan" and "15th Five-Year Plan", especially the small and medium-sized off-river pumped storage projects close to the load center and with short construction period. It will take 5 to 10 years to basically complete the transformation and upgrading of the power grid, which is synchronous and even moderately ahead of the grid. It will take the lead in building China's energy storage system with pumped storage as the main energy, supplemented by electrochemical and other energy storage methods, to help China's energy transformation process.Editor/Ma Xue