Lay out a new track for the energy storage industry and accelerate the demonstration and application of energy storage technology in power systems (1)

Energy storage is an important technology and basic equipment to support the new power system. It is of great significance to promote the green transformation of energy, respond to extreme events, ensure energy security, promote high-quality energy development, and achieve carbon neutrality at peak carbon. In July 2021, the National Development and Reform Commission and the National Energy Administration issued the "Guiding Opinions on Accelerating the Development of New Energy Storage", vigorously promoting the construction of power-side energy storage projects, actively promoting the rationalization of grid-side energy storage, and actively supporting user-side energy storage Diversified development. By 2025, the installed capacity will reach more than 30 million kilowatts, realizing the transformation of new energy storage from the initial stage of commercialization to large-scale development. The "White Paper on Energy Storage Industry Research in 2021" shows that among the new projects put into operation in 2020, the installed capacity of energy storage on the new energy power generation side is the largest, with a year-on-year increase of 438%. In the future, new energy storage will show explosive growth. Shanghai urgently needs to seize the new track of the energy storage industry, vigorously activate the value of energy storage resources, and promote the large-scale development of advanced energy storage technologies.

Energy storage technology is an important part of the six links of "mining-generation-transmission-distribution-use-storage" in the process of power grid operation. After the energy storage link is introduced into the power system, it can effectively realize the demand side management, eliminate the peak-valley difference between day and night, and smooth the load. It can not only make more effective use of power equipment, reduce power supply costs, but also promote the application of renewable energy It can be used as a means to improve system operation stability, adjust frequency, and compensate for load fluctuations.

1. Typical application of energy storage technology in power system

The research and development of energy storage technology has always been valued by the energy, transportation, electric power, telecommunications and other departments of various countries. Electric energy can be converted into chemical energy, potential energy, kinetic energy, electromagnetic energy and other forms of storage. According to its specific methods, it can be divided into four types: physical, electromagnetic, electrochemical and phase change energy storage.

When the pumped storage power station is put into operation, it must be equipped with two reservoirs (upper and lower pools) upstream and downstream. During low load periods, the pumped storage equipment works in the motor state, pumping water from the downstream reservoir to the upstream reservoir for storage, and pumping and storing water during peak loads. The equipment works as a generator, using the water stored in the upstream reservoir to generate electricity. Pumped energy storage is the most widely used energy storage technology in power systems. Its main application areas include peak-shaving and valley-filling, frequency modulation, phase modulation, emergency backup, black start, and provision of system backup capacity. It can also improve system Operational efficiency of medium thermal power plants and nuclear power plants.

Compressed air energy storage power station (CAES) is a gas turbine power plant for peak regulation. It mainly uses the remaining power to compress air when the grid load is low, and stores it in a high-pressure sealed facility with a typical pressure of 7.5MPa, and releases it during peak power consumption. Come out to drive the gas turbine to generate electricity. CAES construction investment and power generation costs are lower than those of pumped storage power plants, but its energy density is low and limited by terrain conditions such as rock formations. The possibility of gas leakage and cracking of CAES gas storage is extremely small, with high safety factor and long service life. Power generation system backup.

The flywheel energy storage system is composed of high-speed flywheel, bearing support system, motor/generator, power converter, electronic control system and additional equipment such as vacuum pump and emergency backup bearing. At valley load, the flywheel energy storage system is powered by the power frequency grid to drive the flywheel to rotate at high speed, store energy in the form of kinetic energy, and complete the conversion process of electrical energy to mechanical energy; when peak load occurs, the high-speed rotating flywheel acts as the prime mover to drag The motor generates electricity, and the power converter outputs current and voltage to complete the energy release process of mechanical energy-electrical energy conversion.

The superconducting magnetic energy storage system uses coils made of superconductors to store magnetic field energy, and does not require conversion of energy forms during power transmission. It has fast response speed (ms level), high conversion efficiency (≥96%), and large specific capacity/specific power, etc. Advantages, real-time large-capacity energy exchange and power compensation with the power system can be realized. The superconducting magnetic energy storage system is relatively simple in technology, without rotating mechanical parts and dynamic sealing problems, and can fully meet the requirements of transmission and distribution network voltage support, power compensation, frequency regulation, and improvement of system stability and power transmission capacity.

Supercapacitor energy storage is developed according to the theory of electrochemical double layer, which can provide powerful pulse power. When the electrode surface is in an ideally polarized state during charging, the charge will attract the opposite-sex ions in the surrounding electrolyte solution, making it attach to the electrode surface, forming The electric double layer constitutes the electric double layer capacitance. Due to the very small distance between the charge layers (generally less than 0.5mm), and the special electrode structure, the surface area of the electrode increases by tens of thousands of times, resulting in a huge capacitance. However, due to the low withstand voltage of the dielectric and the existence of leakage current, the storage energy and holding time are limited, so they must be used in series to increase the charge and discharge control circuit and system volume.

The battery energy storage system is mainly a system that uses lithium batteries/lead batteries as energy storage carriers to store electric energy and supply electric energy within a certain period of time, and the provided electric energy has the functions of smooth transition, peak shaving and valley filling, frequency modulation and voltage regulation, etc. . It has the ability to control the active power flow, and can simultaneously adjust the active power and reactive power of the access point, providing a fast response capacity for the high-voltage transmission system. Because the battery energy storage has relatively mature technology, large capacity, safety and reliability, and low noise Low cost, strong environmental adaptability, easy installation and so on.

2. Typical cases of power energy storage demonstration projects in brother provinces and cities

(1) Zhejiang explores energy storage application scenarios and business models

In November 2021, the Zhejiang Provincial Development and Reform Commission and the Provincial Energy Bureau issued the "Implementation Opinions on Accelerating the Demonstration Application of New Energy Storage in Zhejiang Province". In the next three years, a new energy storage demonstration project of 1 million kilowatts will be built on the grid. Five" and strive to achieve the development goal of new energy storage demonstration projects of about 2 million kilowatts. Zhejiang is actively building a provincial-level demonstration area for the new power system of the State Grid, exploring a new energy storage development model, adapting to the development of the new power system, and focusing on supporting the construction of new energy storage projects that are centralized and large-scale and distributed on a platform to aggregate new energy storage projects for the power system. Provide capacity support and peak shaving capabilities. At present, Zhejiang has spawned new business forms and new models such as "new energy + energy storage" joint operation, shared energy storage, and "one-stop" service for energy storage and grid connection, and has achieved a lot of success.

In December 2021, the 110kV Yueci Substation and the 10kV Qianwan Energy Storage Power Station in Ningbo Hangzhou Bay New District were successfully put into operation. As the first grid-side prefabricated energy storage power station in Zhejiang Province, the Qianwan energy storage power station covers an area of only two basketball courts, but it uses lithium iron phosphate batteries with high energy density and long cycle life, which can achieve high Efficient energy storage. Realize charging and energy storage during low-peak periods of electricity consumption, and discharge to the grid through substations during peak hours, so as to make up for the gap in time and enhance the flexibility and security of power supply.

(2) Guangdong Province actively promotes the innovative development and application of new energy storage technologies

In April 2021, the AGC (Automatic Generation Control Device) energy storage-assisted frequency modulation project of Guangdong Huadian Shaoguan Thermal Power Company was completed and put into operation. This is the first power-side energy storage system in China that adopts a high-voltage cascade + 1C battery solution. China Southern Power Grid actively promotes the innovative development and application of new energy storage technologies. The joint frequency regulation of thermal power units with energy storage systems is of great significance to effectively solve the shortage of frequency regulation resources in regional power grids and improve the reliability and safety of power grid operation. The project is equipped with a lithium iron phosphate battery system with a long cycle life. The total capacity of the energy storage system is 10 MW/10 MWh. up to 88%), fast response and flexible adjustment (0.604 seconds to achieve full power output), superior battery balancing effect, small footprint, etc., the continuous charging and discharging time is up to 51 minutes, and the battery cycle life is about 5000 times. The core indicators Both reached the domestic leading level.

(3) Shandong's first energy storage demonstration project officially put into operation in Huadian

In December 2021, the 9 MW/MWh energy storage and frequency modulation power station of Huadian International Laicheng Power Plant successfully completed the 168 trial operation, marking the official commissioning of the first energy storage demonstration project in Shandong Province. Laicheng Power Generation is transporting four 300,000-kilowatt coal-fired power units, which are important power sources for the high-load areas of the Luzhong Power Grid, and are also the main units for peak and frequency regulation in the Shandong Power Grid. In order to further improve the regulation performance of the unit and adapt to the competitive needs of the power grid frequency regulation market, Laicheng Power Generation invested in the construction of a 9 MW/MWh energy storage frequency regulation power station. Taking advantage of the advantages of fast and high-precision regulation of electric energy storage, through the "fire-storage combined frequency regulation "Real-time adjustment of power generation output to meet the real-time balance between power generation output and user-side load. After the project is put into operation, it will greatly improve the frequency regulation performance of Laicheng generator sets, increase the income of enterprise ancillary services, improve the operation reliability of Shandong power grid, increase the capacity of renewable energy consumption, and play a role in accelerating the construction of a new power system with new energy as the main body. Good demonstration effect.

(4) Lianyungang Port completed and put into operation the first integrated system of shore power and energy storage in China

In April 2021, the first domestic shore power energy storage integrated system was completed and put into operation in Lianyungang Port. The popularization and application of shore power technology is of great significance. The project has an energy storage power station with a power of 5 megawatts, which can meet the demand for shore power access of more than 10 megawatts in total or more than 3 megawatts in a single berth, and there is enough margin when the shore power is operating at full capacity , to meet the access requirements of various random and impact loads such as port cranes and gantry cranes. The promotion of shore power technology is the best solution to reduce the pollution of ships in port. Through the "oil-to-electricity" transformation, the energy consumption of ships can be replaced during port calls, which can greatly reduce the pollutant discharge of ships.