The grid energy storage effectively increases the regulatory means and capabilities of the power grid, which is conducive to the safe and stable operation of the power grid. With the rapid development of new energy power grids, safety issues are becoming more and more serious.
This article introduces grid energy storage technology, analyzes demand, and energy storage optimization planning technology. Finally, the development and application of grid energy storage technology is prospected, and the benefit value of energy storage applications for the future is explored.
1. The concept of power grid-side energy storage
Grid energy storage is a new format that has emerged in recent years and has attracted a lot of attention from the top 10 energy storage lithium battery companies. From the technical level to the policy level, to the business model and many other aspects, it has become the focus of the energy storage industry.
It is clear that grid-connected power generation companies, energy storage power stations and comprehensive energy service providers with automatic generation control (AGC) regulation capabilities can carry out power frequency regulation auxiliary service transactions in an orderly manner, providing policy guarantees for energy storage to participate in the power auxiliary service market.
With the continuous progress of energy storage technology and the orderly advancement of various policies, grid energy storage has evolved from operation mode and functional positioning and gradually matured. China's energy storage technology demonstration project on the grid has also emerged.
The grid energy storage station adopts the shared business model of full market operation to verify the technical feasibility of the energy storage station to solve the problem, and makes a beneficial attempt for the market-oriented operation of the grid energy storage station.
In the application process of energy storage technology, grid energy storage plays an important role in ensuring the stable operation of the power grid, improving the acceptance capacity of new energy, and regulating power quality.
2. Current status of power and user energy storage applications
● Power and user energy storage application status
With the rapid development of the global new energy industry, China has become a leading country in the development of energy storage technology and has played an important role in promoting the development of the energy storage industry, especially in electrochemical energy storage.
According to the different application scenarios of energy storage, it can be divided into grid energy storage, power measurement energy storage and user energy storage. The user side is also home energy storage and mainly used in user time-use price management, capacity management and power quality adjustment, and is the main means to help power users realize time-use power price management.
Users charge the energy storage system when the electricity price is low and discharge it when the electricity price is high. So as to reduce their maximum load, achieve the purpose of reducing capacity costs, and improve the quality and reliability of power supply.
Battery energy storage systems have been applied on a large scale on the power supply side and the user side. As an important part of renewable energy systems and smart grids, energy storage technology plays a broad and important role in the electricity market. The results show that the energy storage industry has made significant progress in technological innovation, market development and application demonstration.
3. Current status of grid energy storage applications
Grid energy storage is different from the power supply side and the user side, and is a type of energy storage used in the field of transmission and distribution. As a high-quality active and reactive power regulating power supply in the power grid, its main function is to effectively improve the safe operation level of the power grid and is of great significance in the backup of the power grid system, alleviating the peak load power supply pressure and peak frequency regulation.
The application of grid energy storage needs to combine the characteristics of regional power grids with the multi-functional application requirements of energy storage. In large-scale energy storage planning, it is necessary to consider whether the location of energy storage in the grid is appropriate.
As a two-way power element, the access location in the power system will directly affect the network loss, and then affect the system voltage level. Therefore, it is particularly important to choose a reasonable layout to improve the safety and stability of system operation.
Since the application of energy storage technology on the grid does not yet have economies of scale, the selection of reasonable configurations to improve the economic level of energy storage applications has also become an important research content.
4. Grid energy storage technology
The location and configuration of energy storage have an impact on the operating stability and economy of the system, so it is of great significance to study the site selection and configuration methods of energy storage on the grid side.
The application of China's grid energy storage technology has just entered the development period, and the application of energy storage technology in peak shaving and valley filling, improving system reliability, and grid frequency regulation is gradually being carried out.
China has also made further progress in improving grid energy storage. In order to improve the voltage stability of the distribution system, a timing voltage sensitivity method is proposed to optimize the energy storage location. From the perspective of energy storage configuration, the existing research is not comprehensive enough to bring benefits and effects of energy storage on the grid side, and involves less safety, stability and economic benefits brought by energy storage to the entire power grid system.
In summary, the application advantages of grid energy storage technology are outstanding, but the location configuration of grid energy storage has a direct impact on the safe and stable operation of the system, and the cost of grid energy storage is relatively high.
5. Market analysis of grid energy storage
● Theoretical analysis
Since the uncertainty and volatility caused by new energy output cannot be changed, the peak-valley characteristics of electricity load also exist objectively, which makes it difficult for the power system to balance supply and demand in real time. Not only that, new energy has also brought new challenges to current carrying capacity, voltage stability, and network loss of power grid lines.
● Wind power generation
Due to the limited ability to predict wind power output, when the wind power penetration rate in the power grid is high, the randomness of wind power output will have a certain impact on the power grid. In addition to wind power output affecting grid stability, other new energy output also has an impact on grid stability.
● Solar power generation
In the process of large-scale grid connection of photovoltaic storage power generation, the voltage of countercurrent generation is first affected. Secondly, due to the unique volatility of photovoltaic power generation, the active allocation is insufficient.
At the same time, when multiple photovoltaic units are connected to the grid at the same time, the normal operation of the power grid is affected. The solar batteries like off grid solar batteries can also be used to promoted the efficiency and guarantee the stable operation of the power grid.
6. Optimization of grid energy storage
● Configuration economy
Taking the economy into account is an inevitable development trend to realize the promotion and application of grid energy storage technology, and the application of grid energy storage systems is affected by factors such as technical economic level.
After fully considering the life cycle cost of energy storage applications, the optimal configuration is achieved with this goal to form a scheme. With the continuous advancement of grid energy storage technology, the service life and utilization efficiency of the system have been greatly improved, reducing energy loss and increasing economic benefits.
● Application difficulties
It can be seen that the government has built a platform to promote the grid energy storage industry to play its role as a market mechanism, which provides the possibility of multi-channel profitability for energy storage in the application of auxiliary services.
However, due to the limited transmission capacity of new energy sources such as wind power and photovoltaics, these three restrict each other and produce contradictions, which puts forward higher requirements for the transmission capacity and safe and stable operation capacity of the power grid. Therefore, at the technical level, it is also necessary to establish a more complete grid energy storage configuration.
At present, the development of China's grid energy storage technology is still in a period of improvement, and relevant policies and regulations need to be further improved. Policy formulation for grid energy storage technology should have continuity and sustainability.
The healthy development of the energy storage industry requires the establishment of a sound standard system to effectively standardize the rational application of energy storage technology. grid energy storage technology has diversified forms, many application scenarios, and diverse functional characteristics, so boundary conditions should be determined according to different applications, and corresponding typical schemes should be tailored.
This article mainly analyzes the application status of grid energy storage outside China, then sorts out the location configuration technology and demand of grid energy storage, and gives corresponding suggestions and prospects for the development and application of grid energy storage technology, so as to provide reference for improving the economy of grid energy storage technology.