Analysis of Key Operational Performance Indicators for Energy Storage Power Stations
As of March 17, 2025, the introduction of Document No. 136 marks a significant shift away from the “strong allocation” model, indicating that energy storage projects will transition from being primarily policy-driven to a market-driven development model. This change signifies a true marketization challenge for energy storage projects. Once fully integrated into the electricity market, energy storage power stations will generate revenue by participating in various services, whether in the electricity spot market, ancillary services market, or through low storage and high discharge operational modes in commercial and industrial settings. In this competitive environment, energy storage power stations will adhere to the essential market principle of “survival of the fittest.”
In the early stages of market development, the quality of energy storage equipment varied significantly, with some manufacturers focusing more on marketing than on research and development. Consequently, energy storage projects tended to prioritize construction over operational performance, resulting in low overall utilization rates and various issues. The actual operational status of projects has not received adequate attention or problem-solving efforts. In the future, the operational capability of energy storage projects will be the most critical factor in assessing the quality of power stations; “good performance on paper is not as valuable as good operational performance.” The profitability of various projects will differ, and even energy storage power stations of the same type in the same region may experience substantial variations in revenue due to differences in operational performance.
To effectively measure the operational performance indicators of energy storage power stations, four key points are essential:
- Grid Interaction Performance: For energy storage power stations subject to grid dispatch control, particularly those connected to both the power source and the grid, their grid connection performance must meet the safety and stability requirements of the power system. In practical engineering, once connected to the grid, energy storage power stations are required to commission third-party testing organizations to conduct grid connection tests. These tests evaluate the power control, primary frequency modulation, inertia response, fault ride-through capability, operational adaptability, power quality, and automated dispatch of the energy storage system to ensure compliance with relevant technical standards. If an energy storage power station fails to meet grid connection performance indicators, it will adversely affect its normal commercial operation and will be subject to assessments based on the “two detailed rules.” For example, in terms of primary frequency modulation, the energy storage power station should have a frequency modulation capability with a dead zone set at ±(0.03~0.05) Hz, a modulation rate of 0.5~3%, and a modulation response time not exceeding 4 seconds.
- Charge and Discharge Efficiency: Charge and discharge efficiency is a crucial metric for evaluating the performance of energy storage power stations. It is defined as the ratio of the discharged energy to the charged energy during the evaluation period, reflecting the efficiency of energy conversion within the storage system. This efficiency is closely related to equipment selection, engineering design, operational methods, and auxiliary power consumption. Improving the charge and discharge efficiency of energy storage power stations can reduce energy loss and enhance their supporting and regulating capabilities for the grid, thereby maximizing revenue. For instance, newly commissioned shared energy storage projects achieve a single charge and discharge efficiency of approximately 82% to 89%, with annual efficiencies ranging from 76% to 86%. Moreover, as the lifespan of storage batteries increases, efficiency may decline by an additional 1% to 2%. The charge and discharge efficiencies can vary significantly among different projects, and improvements can be made by selecting energy-efficient transformers, low-loss energy storage converters, enhancing battery thermal control design, and optimizing the operational strategies of thermal management systems.
- Availability Rate: The availability rate reflects the reliability of the equipment in energy storage power stations. It is calculated as the sum of the charge and discharge time and the hot standby time divided by the total evaluation period. The quality of energy storage equipment varies widely among different manufacturers, leading to significant disparities in availability during project operation. For example, some lithium battery energy storage projects can achieve nearly “maintenance-free” operation due to high operational stability, while others frequently encounter various equipment malfunctions like abnormal communication in storage units, frequent alarms for battery charge and discharge voltage, overheating of IGBT modules, and leakages in liquid cooling systems, necessitating frequent downtime for repairs. This not only increases maintenance costs but also decreases the availability rate of the energy storage station.
- Discharge Capacity: The usable discharge capacity of energy storage power stations is directly related to the charge and discharge efficiency and the state of health (SOH) of the storage batteries. As the batteries age, their charge and discharge performance will experience permanent degradation, leading to a gradual decrease in the usable discharge capacity. The SOH is closely associated with the charge and discharge multiples, depth of discharge, battery type, operational temperature, and the topology of the energy storage unit. For example, while various battery manufacturers claim their products can achieve 8,000, 10,000, or even 15,000 cycles, the actual cycle life of batteries in projects can vary widely under the same evaluation standards (e.g., 25°C, 80% SOH). Some manufacturers do not meet their claimed lifespans, with some early commissioned storage batteries retiring after less than three years despite being designed for a ten-year lifespan, resulting in a total discharge capacity far below expectations.
2025 CIES Energy Storage Conference
The CIES 2025 Energy Storage Conference, co-organized by the Energy Storage Application Branch of the China Chemical and Physical Power Industry Association, China Energy Storage Network, and Digital Energy Storage Network, is set to feature expert academic support from the Expert Committee of the Energy Storage Application Branch. The conference will include an opening ceremony with invited academic reports, innovative integration of intelligent distribution networks and new energy storage, new power systems and grid dispatch, collaborative development of new energy storage and renewable energy bases, international energy storage, electric auxiliary services, spot trading and capacity markets, industrial green microgrids, national energy storage standards promotion, and integrated solutions for intelligent new energy storage systems, among other specialized sessions.
During the conference, several research outcomes will be released, including the “2025 White Paper on the Development of China’s New Energy Storage Industry,” “2025 White Paper on Industrial Green Microgrid Development,” and reports on “2025 Bidding and Price Analysis for New Energy Storage Projects” and “2025 Analysis of Typical Applications and Development Trends in New Energy Storage.” It is expected to attract over 60,000 attendees from government agencies, research institutions, grid companies, power generation groups, EPC contractors, system integrators, energy storage device manufacturers, energy service providers, project developers, investment institutions, and international buyers.
Since its inception in 2011, the China International Energy Storage Conference and Exhibition (CIES) has consistently upheld high-end, quality, and international standards, driving over 500 billion yuan in domestic and international supply chain and channel cooperation within the energy storage industry. It has facilitated local government investment projects exceeding 100 billion yuan and supported various capital collaborations amounting to 300 billion yuan. This year’s exhibition will feature a “4+1+1” exhibition area, showcasing products and corporate images from energy storage system integration, power generation groups, electrical equipment, temperature control equipment, control systems, energy storage batteries, testing and certification, and fire safety.
The exhibition aims to focus on cutting-edge global technologies and practices within the energy storage sector, actively establishing communication channels between governments and enterprises, exploring new pathways for high-quality development in the energy storage industry, and promoting the deep integration of specialized, refined, unique, and innovative technological, capital, and service elements. It will showcase new products, technologies, equipment, and services from both domestic and international markets, helping exhibitors enhance brand influence and recognition, actively expand domestic and international market channels, improve the competitiveness and market share of controllable products, and accelerate the core value growth of Chinese energy storage brand enterprises.
Welcome to attend the 2025 15th China International Energy Storage Conference and Exhibition.
