New energy storage is an energy storage technology with output power as the main form except pumped storage. It has the characteristics of precise control, quick response, flexible configuration and four-quadrant flexible power adjustment. It can provide power system with multi-time scales, full-process balance ability, support ability and regulation ability, and is an important supporting technology for building a new power system with new energy as the main body. Through deep integration with digital and intelligent technologies, new energy storage will become a hub for coupling and conversion of multiple energy subsystems such as electricity, heat, cold, gas and hydrogen, which can promote open sharing and flexible trading of energy production and consumption, realize multi-energy collaboration, support the construction of energy Internet and promote the development of new energy formats.
The Tenth Five-Year Plan for Scientific and Technological Innovation in the Energy Field (hereinafter referred to as the Plan) focuses on the strategic goal of "double carbon", focuses on improving the regulation ability, comprehensive efficiency and security guarantee ability of energy and power systems, and supports the construction of new power systems and the green, low-carbon and efficient transformation of energy. The Plan closely follows the positioning of new energy storage function in the Tenth Five-Year Plan, and combines the development status of new energy storage technology, and deploys key tasks around energy/capacity energy storage technology and equipment and system integration technology, power/standby energy storage technology and equipment and system integration technology, common key technology of energy storage batteries, collaborative aggregation technology of distributed energy storage and distributed power supply, etc., and determines four centralized research projects, three demonstration tests and one application promotion, and formulates a technical roadmap to accelerate the scale of new energy storage.
First, the development achievements of new energy storage technology
(1) The new energy storage technology has developed rapidly, showing a good trend of "letting a hundred flowers blossom".
In electrochemical energy storage technology, the performance of lithium-ion battery is greatly improved, the energy density of battery is doubled, and the cycle life is increased by 2 ~ 3 times; The cost drops rapidly, and the construction cost of energy storage system drops to 1200 ~ 1800 yuan/kWh；; The cost of leveling electricity is reduced to 0.58 ~ 0.73 yuan/kWh (according to the energy storage cycle once a day), and the industrial chain continues to improve, basically realizing localization, which has initially met the conditions for large-scale commercial development. In terms of flow battery, the technology of all-vanadium flow battery sticking has been overcome, and the localization of key materials, components, unit systems and energy storage systems can be basically realized. The cycle life has exceeded 16,000 times, and the construction cost of energy storage systems has been reduced to 2,500 ~ 3,900 yuan/kWh. The pilot demonstration of a 100 MW project is under construction. Lead-carbon batteries have made great progress, with a cycle life of 5,000 times, and the construction cost of energy storage system has been reduced to 1,200 yuan /kWh, achieving megawatt to tens of megawatt applications. Other electrochemical energy storage technologies, such as lithium ion battery, sodium ion battery, liquid metal battery and metal-air battery, have no practical value. In the mechanical energy storage technology, a new type of compressed air energy storage was studied, and a great breakthrough was made in key technologies, and the experimental demonstration of 10MW compressed air energy storage technology was realized. In the aspect of flywheel energy storage, the key technologies such as flywheel, magnetic suspension and motor system have been mastered independently, and the demonstration application of dynamic peak shaving, dynamic UPS and power quality management of drilling rig has been realized. In the electromagnetic energy storage technology,The hybrid capacitor has made a great breakthrough in super capacitor energy storage. The energy density has reached more than 40Wh/kg, the power density has reached more than 1kW/kg, and the number of charge and discharge cycles has exceeded 50,000. Thermal storage and hydrogen energy storage technologies have also achieved a breakthrough in the principle prototype.
(2) The new energy storage application technology has been continuously broken through, the application scale has been steadily improved, and the application scenarios have been continuously expanded, and a number of pilot demonstration projects have been built.
During the "Thirteenth Five-Year Plan" period, China’s energy storage application technology initially broke through key technologies such as energy storage capacity allocation, energy management of energy storage power stations, and coordinated control of source, grid and storage, and successively carried out diversified demonstration projects such as large-capacity energy storage to enhance the friendliness of new energy grid connection, secondary frequency modulation of energy storage units, peak shaving of large-capacity energy storage power stations, distributed energy storage to improve the operational reliability of microgrid, and sharing of energy storage power stations. The related core technical indicators of several demonstration projects have also reached the international level. By the end of 2020, the installed capacity of new energy storage in China is about 3.3 million kilowatts. Except for a few demonstration projects that use compressed air and flywheel energy storage technology, the rest use electrochemical energy storage technology, in which the scale of lithium-ion battery accounts for about 89%, that of lead battery accounts for about 10%, that of flow battery accounts for about 0.7%, and that of super capacitor accounts for about 0.1%. In addition to the improvement of the overall scale, the installed capacity of a single energy storage project is constantly breaking through. According to incomplete statistics, there are about 7 new energy storage projects with installed capacity of 50MW and above in China, and about 48 new energy storage projects between 10MW and 50MW, most of which adopt lithium-ion battery technology. In the projects put into operation, the energy storage scale of power supply side, power grid side and user side accounts for 47%, 18% and 35% respectively. Diversified application scenarios such as "new energy+energy storage", conventional thermal power configuration energy storage, "internet plus" smart energy, smart microgrid and shared energy storage are constantly emerging, among which in 2020, eight projects in Qinghai, Hebei, Fujian, Jiangsu and Guangdong were selected as the first batch of national scientific and technological innovations (energy storage).It covers main scenarios such as renewable energy power generation, thermal power auxiliary frequency modulation, power grid side and user side.
Second, the new energy storage technology faces the situation
In 2017 ~ 2018, the United States, the European Union and Japan successively released the roadmap for the development of energy storage technology, and identified lithium-ion batteries, flow batteries, supercapacitors, compressed air energy storage and flywheel energy storage as the key technical types, and increased investment in technology research and development. In 2020, the United States released a road map of energy storage challenges, and also discussed metal-based batteries, zinc-based technologies, reversible fuel cells, liquid air energy storage, hydrogen energy storage, etc., paying more attention to technological innovation and industrial chain improvement.
Third, the development trend of new energy storage technology
During the "14th Five-Year Plan" period, the annual installed capacity of new energy in China is expected to reach about 1-120 million kilowatts, which will double the installed capacity of new energy in the "13th Five-Year Plan" year, which will pose an unprecedented challenge to the power system’s capacity to absorb electricity. It is urgent to build a new power system based on new energy storage technology and digital intelligence technology. Even if the layout of new energy development is fully optimized, thermal power flexibility transformation and other measures are put in place, and the assessment of new energy utilization rate is properly liberalized, the installed capacity of new energy storage in China is not less than 30 million kilowatts, which is about 10 times the installed capacity of new energy storage at the end of the 13 th Five-Year Plan. Objectively, it is required that the development of new energy storage must be accelerated to achieve leap-forward development.
However, the current development level of new energy storage technology still faces some bottlenecks that need to be broken through.
First, the maturity of new energy storage technology needs to be further improved. In terms of electrochemical energy storage, lithium-ion batteries need to further improve their cycle life and calendar life, and strengthen research on the development of batteries and modules with low thermal power, high energy efficiency and high safety. The progress of iron-chromium flow battery technology is slow, and the full localization and batch preparation of key materials, as well as the efficient and intelligent assembly technology of high-power stacks need to be developed. The modularity, integration and intelligence of lead-carbon batteries still need to be further improved. In terms of mechanical energy storage, key ontology technologies and application technologies such as system design and off-design regulation for application scenarios, high-efficiency and high-load compression/expansion machine, array heat storage heat exchanger and power system coupling control still need to be tackled. In electromagnetic energy storage, hybrid capacitor energy storage technology has been developed, but the technical maturity still needs empirical test.
Second, the cost of new energy storage is still high, and there is still a big gap from the full commercial application. Taking battery energy storage as an example, the cost of non-battery part still accounts for 50% of the cost of energy storage system, and reducing the cost of non-battery part will be an important task in the future.
Third, the safety problem of energy storage system needs to be solved urgently. In recent years, the safety accidents of electrochemical energy storage power stations at home and abroad have been frequent, which has aroused widespread concern and concern in the society and industry. The technical level of system safety protection and fire fighting can not fully meet the needs of large-scale application of energy storage. It is urgent to carry out research on multi-layer safety protection strategies such as monomer, module and system, do a good job in safety technology upgrading and fire protection scheme development, study efficient thermal design and management strategies, and do a good job in system safety and reliability technology development with power scale of 100 MW or above.
Fourth, the control strategy of energy storage operation needs to be optimized. At present, due to the limitations of data acquisition mode, response speed and control accuracy, the dispatching control strategy of energy storage power station considering different energy storage time scales and response characteristics, multi-point decentralized layout aggregation control and coordinated optimization with various power sources needs to be further improved. In actual operation, the benefits of energy storage facilities to the power system have not been fully exerted, especially with the deep coordinated development of energy storage and new energy power generation in the future, the coordinated control technology of grid wind, light and storage may become a bottleneck restricting the value creation of energy storage system.
Fifth, the energy storage industry chain has not yet formed a closed loop, and the recycling of waste energy storage facilities still needs to be established and improved.
Four, the key tasks and prospects for the development of new energy storage technology
In the Plan, energy/capacity energy storage technology and equipment and system integration research are deployed for energy storage application scenarios such as power grid peak shaving and valley filling and centralized renewable energy grid connection. In terms of centralized research, we will deploy and develop long-life, low-cost and high-safety lithium-ion batteries, break through the technology of special module balance and energy management for lead-carbon batteries, carry out research on key materials, stack design and integrated design of system modules for high-power flow batteries, develop new generation of high-performance energy storage technologies such as sodium ion batteries, liquid metal batteries, sodium-sulfur batteries, solid-state lithium-ion batteries, energy storage lithium-sulfur batteries and water-based batteries, and develop energy storage technologies such as heat storage, cold storage, hydrogen storage and mechanical energy storage. In the demonstration test, the system design and demonstration of GWh-class lithium-ion battery, large-scale compressed air energy storage power station and high-power flow battery energy storage power station were carried out. Strive to complete the demonstration of large-scale air compression energy storage technology and iron-chromium flow battery technology by 2025.
According to the energy storage application scenarios such as enhancing power grid frequency modulation, smoothing intermittent renewable energy power fluctuation and capacity reserve, the Planning has deployed research on power/standby energy storage technology and equipment and system integration. In terms of centralized research, we will carry out research on electromagnetic energy storage technologies such as superconductivity and dielectric capacitors, and develop various power energy storage devices such as electrochemical supercapacitors and high-rate lithium-ion batteries; Research and develop key technologies such as high-power flywheel materials and high-speed bearings, and break through the key technologies of integrating high-power flywheel and high-inertia synchronous camera, as well as the 50MW high-inertia synchronous camera technology based on flywheel. In the demonstration test, promote the design and application demonstration of 10MW super capacitor, high power lithium ion battery and MW flywheel energy storage system. Strive to complete the application demonstration of inertial rotation standby energy storage technology by 2025.
In view of the situation of large-scale configuration of electrochemical energy storage on the new energy side and the power grid side during the 14 th Five-Year Plan period, the Planning has deployed the research on the common key technologies of energy storage batteries. In terms of centralized research, experimental verification and simulation research on predicting long calendar life based on short-term test data of energy storage battery cells and modules are carried out to realize rapid monitoring and evaluation of cycle life and health status of energy storage batteries for more than 25 years; Carry out research on new energy storage battery technology with low cost, repairable and renewable, and develop technologies for residual value evaluation of retired batteries, automatic disassembly of single batteries and material sorting to realize battery repair, cascade utilization, recovery and regeneration; Promote the research on intelligent sensing technology of energy storage units and systems; Promote the research on safety detection, early warning and protection of energy storage batteries throughout their life cycle; Based on the forward design, the design and manufacture of power battery suitable for cascade utilization are carried out, and the key technologies such as cascade utilization scenario analysis, rapid sorting, system integration and operation and maintenance are studied. In the demonstration test, the key technologies such as safety early warning of electrochemical energy storage system, multi-level protection structure and materials of the system are developed, and the key technologies such as overall safety design, intelligent energy management and control, operation and maintenance, cooling and fire fighting of large lithium battery energy storage power stations are demonstrated. Strive to promote the development and application of large-scale energy storage power station system integration technology by 2025.
In view of the trend of vigorously developing distributed new energy and "integration of source, network, load and storage" in the 14 th Five-Year Plan, the Planning has deployed research on collaborative aggregation technology of distributed energy storage and distributed power supply. In the aspect of centralized research, the cooperative aggregation of distributed energy storage systems is studied, the aggregation method of multi-point energy storage systems is put forward, and the series of theories and technologies of peak shaving, frequency modulation and emergency control of multi-point energy storage systems are mastered to realize the cooperative aggregation of distributed energy storage and large-scale clusters of energy storage power stations with wide-area layout; Develop renewable energy resources in islands and tackle key technologies of smart microgrid. In the aspect of application and promotion, it breaks through the cooperative control of distributed energy storage and distributed power supply and regional energy allocation management technology to improve the acceptance of distributed photovoltaic in distribution network; Develop a multi-market trading platform for distributed energy storage based on blockchain technology, and promote the application technology of shared energy storage based on blockchain.
Source: Henan Electrical Industry Association