With the substantial increase in the proportion of wind and new energy connected to the grid, energy storage has ushered in rapid development under the joint action of policies and markets. In 2021, the cumulative installed power of China's electrochemical energy storage market will reach 5.1GW. According to the forecast of China Chemical (601117) and the Physical Power Industry Association, the installed capacity of electrochemical energy storage is expected to reach 40GW in 2025. However, the low utilization rate of energy storage has severely restricted the rapid development of energy storage, which has become a hot issue in the industry. According to the statistics of China Electricity Council, the average equivalent utilization coefficient of electrochemical energy storage projects is 12.2%, the distribution and storage coefficient of new energy is only 6.1%, the distribution and storage coefficient of thermal power plants is 15.3%, the grid energy storage is 14.8%, and the user energy storage is 28.3%. This means that most energy storage stations are idle after investment and construction, unable to effectively play their energy, economic and other aspects. What hinders the efficient use of energy storage? Guoneng Rixin (301162) believes that its root cause mainly lies in two aspects of safety and economy.

Short life, many accidents

The inability to guarantee the safe and long-term operation of energy storage is a major obstacle to the healthy development of electrochemical energy storage. First, the actual life of energy storage is not as expected. According to the statistics of domestic authoritative experts, the power type energy storage system is expected to be 10 years, but the actual operating life is less than 3 years; the energy storage performance system is expected to be 15-20 years, but the actual operating life is less than 8 years. Second, safety accidents of energy storage stations occur frequently, causing immeasurable losses. Energy storage accidents are common around the world. Once an accident occurs in a large-scale energy storage power station, it will cause a large loss of life and property, making energy storage investors and operators shy away.

How to prolong the life of energy storage batteries and avoid energy storage accidents as much as possible? Based on the summary of project experience, Guoneng Rixin suggested to focus on the two core units of the electrochemical energy storage system - PCS and battery. In terms of PCS technology, it adopts a group string solution, and in terms of battery protection, it uses an active early warning platform to expose hidden dangers in advance to avoid unplanned production shutdowns and accidents.

First of all, in terms of PCS hardware, at present, the topology of large-scale electrochemical energy storage power stations is still dominated by low-voltage centralized. Taking the 1.26MW/2.5MWh container as an example, after comparing the advantages and disadvantages of the three types of technical solutions, National Energy Rixin believes that the string solution is simple in design, each cluster is independent, and can prevent circulation, which is the best solution among the three solutions , which can prolong battery life, improve the safety of energy storage stations, and avoid accidents to a certain extent.
Next, in terms of battery software protection, Guoneng Rixin proposed a big data AI algorithm protection solution to solve the three major drawbacks of the current energy storage station battery system operation monitoring that relies heavily on the battery management system (BMS): 1. Failure to identify the defects of the battery itself, aging Early soft failure of depletion; 2. The error of battery state estimation (SOC/SOH/internal resistance) will increase and increase cumulatively; 3. After the battery ages, the factory-set protection threshold will not change.

Guoneng Rixin makes up for the lack of computing power of the BMS itself by modeling and calculating the original data collected by the BMS, realizes cloud calibration, and eliminates accumulated errors. And perform feature extraction and analysis on the battery operation data, realize battery risk prediction and diagnosis in advance, accurately predict the abnormal risk of module consistency, guide equipment maintenance and repair, replace the battery box that may be abnormal in time, and solve the problem of battery pack Problems such as performance degradation and life shortening caused by the latter, ensure the safe operation of the power station and prolong the life of the power station.

High cost, low profit

On the basis that the safety and long-term efficiency of energy storage can be guaranteed, the investment cost of electrochemical energy storage stations is high, while the benefit problems in subsequent operation reduce the enthusiasm of energy storage investors and operators. At present, the profit model of energy storage projects has different profit effects due to different local policies. As provinces such as Shandong, Qinghai, Shanxi, and Gansu gradually release relevant policies for energy storage to participate in the market, new energy storage profit channels are experiencing diversification. How to improve the efficiency of energy storage, so as to re-mobilize the enthusiasm of energy storage investors and operators? National Energy Rixin suggested to take advantage of shared energy storage advantages, and energy storage should adapt to the diversified profitable energy storage market as soon as possible.

Compared with new energy supporting energy storage, the shared energy storage power station has a more scientific and reasonable layout. One shared energy storage power station can realize the frequency modulation and peak shaving function of supporting energy storage for multiple new energy stations, which is convenient for power grid companies to dispatch. By building a shared energy storage power station, referring to the contract energy management model and cooperating with new energy stations, it not only meets the requirements of the power grid company for new energy technology assessment, but also improves the power quality of new energy stations, and reduces the investment and cost of new energy stations. Operational risk, to achieve a win-win situation for all parties.

In the context of marketization, there are currently four main profit models for energy storage: capacity leasing fees paid by new energy power stations, ancillary service market revenue, peak-valley arbitrage, and capacity price compensation. There is coupling between different electricity markets, and they influence each other, including price signals. For example, price changes in the energy market may cause price changes in the frequency modulation market. In the increasingly complex and changeable power market, how to consider and balance uncertainties such as market prices and new energy output, and make overall intelligent regulation is a technical problem.

In order to help energy storage stations adapt to the complex needs of market-oriented development, National Energy Rixin Smart Energy Storage EMS uses a multi-market model to give full play to the flexibility of energy storage, participate in different markets at different times, and proposes that energy storage participate in more types of market services. Energy storage strategy, so as to achieve cross-time and cross-market arbitrage, achieve a win-win situation for energy storage operators and power grids, and comprehensively improve the economic and social value of energy storage.

First, in the electricity market where energy storage participates in the electricity market, a day-ahead-intraday-real-time market multi-time scale rolling optimization model for energy storage participation in the spot market and a frequency regulation market model related to the historical frequency regulation capacity mileage ratio are constructed. On the basis of energy storage life and risk assessment, the optimization and regulation of energy storage spot market is improved, and the influence of comprehensive frequency regulation performance index and time-of-use electricity price is considered to improve the economic benefits of energy storage.

Then cooperate with power forecasting to formulate a strategy to maximize the reduction and exemption assessment of energy storage when there is no power limit, so that the energy storage EMS docking power forecasting system can obtain forecast data, adjust the real-time power of grid connection points, and always control it within the allowable error range of forecasting. Assessment loss.

Find the right way and have a bright future

Under the double-carbon macro background, energy storage is the only way to realize energy transformation, and its healthy and sustainable development is worth exploring. Guoneng Nissin believes that in the contradiction between the high expectations of the industry and the low actual utilization rate, electrochemical energy storage needs to overcome safety and economic obstacles. In terms of security, the PCS hardware adopts a string solution and the battery software AI intelligent protection, which implements both software and hardware, to extend the life of energy storage and avoid accidents, thereby ensuring long-term operation and profitability of energy storage. In terms of economy, with the gradual liberalization of policies in various provinces across the country, shared energy storage can be used as a new idea for energy storage economy, and with the support of algorithm technology, it should speed up adapting to the increasingly diverse energy storage development needs and "catch up" the energy storage market "Express". This article is not only the thinking and discussion of National Energy Rixin, but also hopes to provide ideas for the healthy development of energy storage. Chemical energy storage is booming.

Guoneng Rixin Technology Co., Ltd. (stock code: 301162), established in 2008, is committed to energy data services and application development. With data technology as the core, Guoneng Rixin focuses on product design, software development, data services and overall solutions in the fields of smart power stations, smart grids, smart energy storage, and comprehensive energy services. Among them, power prediction products are firmly in the leading position in the industry.

National Energy Rixin Innovation promotes the energy technology revolution, realizes the digitalization and intelligent upgrading of the energy industry, helps my country's energy "dual carbon" strategic goal, and provides technical products and services for the global energy green and low-carbon development.