中文版
ENGLISH
| The development of new energy storage has entered the fast lane! |
| Release time:2023-02-16 08:41:13| Viewed： |
With the proposal of the "double carbon" goal, renewable energy, mainly wind power and photovoltaic, has gradually become an important part of the new energy system. According to the statistics of the National Energy Administration, the new installed capacity of wind power and photovoltaic power in China will be more than 120 million kilowatts in 2022, and the cumulative installed capacity will be more than 700 million kilowatts. In 2022, the new installed capacity of wind power and photovoltaic power will account for 78% of the new installed capacity in the country, and the new installed capacity of wind power and photovoltaic power will account for more than 55% of the new installed capacity in the country.
However, wind power and photovoltaic power have the characteristics of volatility, intermittence and randomness. Its large-scale installation makes the net load of the power system fluctuate differently in short time (seconds to minutes), long time (hours to days) and ultra-long time (weeks, months and years), requiring the power grid to conduct frequency modulation, intra-day peak shaving and seasonal peak shaving.
The development and application of energy storage technology can help realize the load balance of the new power system with new energy as the main body, effectively suppress the fluctuation of new energy grid connection, and promote the consumption of renewable energy.
New energy consumption accelerates the demand for energy storage
At present, "new energy+energy storage" has become an important development model of the new energy industry. Many provinces and cities in China have also issued new energy allocation and storage documents, which put forward clear requirements for the allocation and storage of wind power and PV. The allocation and storage ratio is mostly 10-15%, and the duration is more than 2 hours.
With the further increase of the proportion of new energy generation, new energy distribution and storage will become the mainstream mode to solve the problem of new energy consumption and maintain the stability of the power grid. Specifically, on the power generation side, energy storage can participate in renewable energy grid connection, power peak regulation, system frequency regulation and auxiliary dynamic operation. On the grid side, energy storage can play a role in supporting the power supply guarantee, improving the system regulation capacity and supporting the high proportion of new energy export. On the user side, energy storage can be used to improve the level of spontaneous self-use of electricity, carry out arbitrage of peak-valley price differences, manage capacity electricity charges, and improve power quality.
Diversified development of new energy storage technology
Among all kinds of energy storage technologies, pumped storage technology is mature and reliable, with low cost of energy storage in the whole life cycle, and is the main force of current energy storage installation. According to the Medium and Long-term Development Plan for Pumped Storage (2021-2035) issued by the National Energy Administration in September 2021, the total scale of pumped storage production will double from the 13th Five-Year Plan to more than 62 million kW in 2025; By 2030, the total scale of pumped storage put into operation will double again compared with the "Fourteenth Five-Year Plan", reaching about 120 million kW.
By the end of 2022, the cumulative installed capacity of energy storage projects that have been put into operation in China reached 59.4GW, up 37% year on year. Among them, pumped storage still accounts for the largest proportion, with a cumulative installed capacity of 46.1GW. However, pumped-storage power stations have shortcomings such as inflexible site selection, large construction investment scale and long construction period, which cannot meet the demand of rapid increase of new energy installed capacity and the requirements of new power system for flexible configuration and diversification of energy storage. Therefore, the new energy storage technology is expected to play the role of power system regulation and security protection in various source and network load scenarios together with pumped storage during the "14th Five-Year Plan" and "15th Five-Year Plan".
According to statistical data, the scale of new planned new energy storage projects under construction in China will reach 101.8GW/259.2GWh in 2022, and most of the projects will be completed and connected to the grid within 1-2 years. It is estimated that during the "14th Five-Year Plan" period, the compound annual growth rate of new energy storage will remain between 55-70%.
The new energy storage technology can be divided into chemical energy storage and physical energy storage. The former includes lithium ion battery, liquid flow battery, sodium ion battery and hydrogen energy storage; The latter mainly includes compressed air energy storage, flywheel energy storage and gravity energy storage.
Among the new energy storage technologies, lithium-ion battery still occupies an absolute position at present. Lead-carbon battery technology is relatively mature and low cost, and occupies a certain market share in the standby power supply. Other new energy storage technologies, such as sodium ion battery, liquid flow battery, compressed air, gravity energy storage, hydrogen energy storage, are still in the early stage of development. In the future, with the improvement of safety, kilowatt-hour cost, initial investment cost and cycle life, new energy storage technology is expected to achieve breakthrough development during the "Fourteenth Five-Year Plan" period.
With the rapid development of the domestic power battery industry, lithium-ion batteries have formed a complete industrial chain, which is suitable for short-term and long-term energy storage in the field of energy storage. In the future, it is still necessary to improve the performance and safety of lithium energy storage batteries through the improvement of battery materials, cell structure, PACK process and other aspects, including but not limited to the material and structure innovation of lithium manganese iron phosphate material, anode lithium supplement technology, blade battery, 4680 large cylindrical battery, etc. With the development and success of solid-state battery technology in the future, it will further realize the energy density of 400-500Wh/kg and high safety.
Lead-carbon battery is a kind of capacitive lead-acid battery by adding activated carbon into the negative electrode of lead-acid battery, which greatly improves the charging and discharging performance on the basis of the original power density of lead-acid battery. At the same time, lead-carbon battery is safe and reliable, low cost per kilowatt hour, and easy to recycle lead. It is one of the current relatively economic and feasible technical routes for electric energy storage, which is applicable to large-scale and long-term energy storage scenarios.
Liquid-flow battery is a kind of battery technology that contains active substances in liquid electrolyte. Compared with lithium-ion battery, it has the advantages of high safety, long cycle life and recyclable electrolyte, and is one of the large-scale long-term energy storage technologies. However, there are some problems in the performance of liquid flow battery, such as low energy density, low energy storage efficiency, high initial investment cost, etc. It is necessary to develop key materials such as ion exchange membrane, bipolar plate, graphite felt, as well as the demonstration and promotion of ferrochrome and zinc-bromine liquid flow battery system in order to reduce costs and increase efficiency.
The energy storage mechanism of sodium ion battery is similar to that of lithium ion battery in the industrial chain, and its energy density is close to that of lithium iron phosphate battery, which can replace some of the energy storage scenarios of lithium iron battery. However, its industrial layout is still in the initial stage, which requires the commissioning and improvement of the positive and negative electrode material system, electrolyte and fluid collector, and the improvement of the industrial chain. With its rich raw material sources and mature technology, it is expected to emerge in the field of energy storage in the future.
Hydrogen energy storage uses intermittent fluctuations and surplus electricity to produce hydrogen for storage. When the power output is insufficient, the gas turbine or fuel cell is used to generate electricity to supply electricity. It is an ideal form of energy storage for cross-cycle and large-scale. Compared with battery energy storage, it has advantages such as strong adaptability to capacity increase and decrease, and low energy storage cost. However, because the whole process includes hydrogen production and power generation, the overall energy utilization efficiency is low, and the overall economy is poor at present. In the future, it is necessary to improve the conversion efficiency through technological breakthroughs in the process of electrolytic hydrogen production and hydrogen power generation. At the same time, it is necessary to develop and utilize the form of hydrogen storage with high energy density to solve the difficulties of large area of large-scale hydrogen storage and high requirements for containers.
In terms of physical energy storage technology, compressed air energy storage refers to the energy storage method that uses electric energy for compressed air during the low load period of the power grid, and releases compressed air to promote steam turbine power generation during the peak period, which is suitable for high-power and long-term energy storage scenarios. In the future, it is necessary to further study the compressor and turbine with large displacement, high pressure and high efficiency, continuously improve the energy storage efficiency, and realize the landing of the 100-megawatt demonstration project.
Solid gravity energy storage is similar to pumped energy storage. The weight is lifted to a high place by electricity to store gravity potential energy, and the gravity potential energy is converted into kinetic energy by the weight falling, and then into electric energy. It has high safety, strong environmental adaptability, long cycle life, low cost and other characteristics, and is expected to complement lithium battery energy storage and pumped storage. At present, solid gravity energy storage still needs to be continuously verified and solved the problems of automatic and stable operation of the system, and continuously reduce the comprehensive cost, improve the energy conversion efficiency and system scalability.
Flywheel energy storage refers to the energy storage technology that uses the motor to drive the flywheel to rotate at high speed, and then uses the flywheel to drive the generator to generate electricity. It has the advantages of fast response, high power, and long life, and is suitable for short-term and high-energy energy storage scenarios, including high-speed rail kinetic energy recovery, aircraft carrier catapults, aerospace launchers, etc. Compared with the sunset in Europe and the United States, China's flywheel energy storage technology relies on imports of equipment. In the future, all parties need to work together to achieve technical overtaking in corners.
Energy storage technology is an important supporting infrastructure for the large-scale development of new energy. During the "13th Five-Year Plan" period, with the guidance of the national policy and the continuous investment of the industry, China's energy storage technology has developed rapidly, and lithium-ion batteries, liquid-flow batteries, sodium-ion batteries, lead-acid batteries, compressed air and other energy storage technologies have approached the international advanced level. During the "Fourteenth Five-Year Plan" period, China will continue to adhere to the innovation-led, diversified development and actively promote the development and implementation of new energy storage technologies.
At present, the development of new energy storage technology still faces problems such as the high cost of lithium-ion batteries, the new energy storage price mechanism has not been established, the business model needs to be explored, the lack of new energy distribution and storage standards, the difficulty of supervision and the insufficient support of the national legal level.
At the level of different energy storage scenarios, the energy storage technology at the sub-second scale can basically meet the requirements, while there are still some gap technologies and security problems in the medium and long-term energy storage technology. Therefore, the development and promotion of medium and long-term energy storage technology and high proportion of renewable energy active support technology will be an important development trend of the energy storage industry. It is expected that the construction of large-scale energy storage demonstration projects of 100 megawatts will also become the norm in the next few years.
At the same time, the application of new energy storage technology needs to combine the actual needs of the new power system, improve the stability of the power system, the reliability of power consumption by end users and the technical economy as the guide, improve the construction of laws and regulations, the price mechanism of energy storage and the exploration of business models, and promote the high-quality development of new energy storage according to local conditions and step by step. |
