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Rejecting the misleading short-term RTE metrics, Sungrow is empowering the entire lifecycle of industrial and commercial energy storage.
At the beginning of this year, the government clarified that renewable energy generation should be fully market-oriented, prohibiting the requirement of energy storage configuration as a prerequisite for new renewable energy projects. Energy storage is transitioning from a policy-driven approach to a market-oriented one. Experts highlight that, following this policy introduction, greater attention should be paid to the issues of cost recovery and investment returns in new energy storage systems.
For battery energy storage systems participating in power trading, the round-trip efficiency (RTE) and the selection of cycling strategies significantly influence the performance and cost-effectiveness of these systems. On March 5th, during the 2025 20th China (Jinan) International Solar Energy Utilization Conference and the 4th China (Shandong) New Energy and Energy Storage Application Expo, Sungrow showcased its new commercial energy storage product, PowerStack 255CS.
At the product launch, Li Canlin, Deputy General Manager of Sungrow’s China Solutions, stated, “Efficiency is a critical factor affecting energy storage returns. Currently, the industry lacks standardized efficiency metrics, with rampant misrepresentations. Many companies use peak conversion efficiency values as performance parameters, which provide no real reference for users.” Sungrow is the first in the industry to propose a 24-hour comprehensive efficiency calculation that includes auxiliary power supply and standby losses under genuine operating conditions. The real-world tests show that the new PowerStack 255CS achieves an all-weather comprehensive efficiency of over 88%.
What does this value signify? The concept of “all-weather comprehensive efficiency” is newly introduced by Sungrow. According to Dr. Cai Zhuang, General Manager of Sungrow’s Product Management Center, this concept emerged from the industry’s reliance on short-term RTE (charge-discharge efficiency) as a core performance indicator. This standard often disregards real operating conditions like auxiliary power and standby losses, leading to users experiencing returns significantly lower than theoretical estimates.
According to the white paper on industrial and commercial energy storage solutions released by Sungrow earlier this year, it is predicted that the installed capacity of industrial and commercial energy storage in the domestic market will reach 9 GWh this year. However, beneath the booming industrial and commercial energy storage market, many issues lurk. Numerous manufacturers exaggerate their specifications, with some claiming energy storage efficiencies of 90%, when in reality, they may fall below 80%. Some companies adopt low pricing strategies to gain market share, but this can lead to inflated expected returns, below-par system performance, significant safety risks from inferior battery cells, extended delivery times, and challenges in later maintenance management.
It is reported that in the energy storage industry, RTE and State of Health (SOH) are key indicators for assessing battery performance and health status. RTE measures the efficiency of conversion, indicating the extent of energy loss during the charge and discharge process, while SOH evaluates the health condition of the battery, quantifying its capacity and performance degradation. Generally, higher RTE and SOH values indicate better battery condition, with minimal performance loss and higher energy conversion efficiency. For instance, in a 10 MWh battery storage system with an RTE of 88%, 8.8 MWh of energy would be returned during discharge.
“The maximum efficiency of 90% and the all-weather system comprehensive efficiency exceeding 88% are based on real data from hundreds of power stations, not lab results,” emphasized Cao Wei, General Manager of Sungrow’s commercial energy storage product line. Further explaining, Li Canlin noted that the PowerStack 255CS optimizes the integration of energy losses across battery cells, PCS losses, and auxiliary losses, achieving an integrated design with precise charging and discharging strategies to ensure maximum efficiency and reliability.
On February 10, 2025, the joint issuance of the “Action Plan for High-Quality Development of New Energy Storage Manufacturing Industry” by eight departments emphasized breakthroughs in various dispatch strategy optimization technologies, multi-device coordinated control, and grid control technology. It also aims to develop systems for evaluating energy storage regulation capabilities and intelligent dispatch decision-making. In industrial and commercial energy storage projects, ensuring returns not only requires accurate RTE values but also relies heavily on the choice of cycling strategies, which significantly influence system performance and return rates.
Considering user cost recovery, the PowerStack 255CS is equipped with an all-weather high-efficiency steady-state system that provides real-time precise charging and discharging strategies through AI technology. This system also features AI biomimetic thermal balance to save 33% on auxiliary power consumption. The product design incorporates an embedded PCS system, enabling efficient energy conversion.
Additionally, the PowerStack 255CS features instantaneous updates of station data, multi-level comprehensive monitoring, real-time electricity price/load forecasting, automatic revenue analysis, one-click strategy distribution, and intelligent decision support for various revenue models such as power trading and virtual power plants. According to Dr. Cai Zhuang, the new PowerStack 255CS boasts an all-weather comprehensive efficiency that is 2% to 4% higher than industry standards, potentially increasing annual revenue by 40,000 for a 1 MWh station, with initial investments reduced by 5% to 10%. This provides users and investors with more stable and reliable revenue guarantees.
Li Canlin believes that “the all-weather system comprehensive efficiency is far more meaningful to customers compared to the maximum RTE promoted by the industry, as it is more realistic.” As the industry shifts focus from “price” to “value,” the customization of industrial and commercial energy storage across all scenarios and the management of its entire lifecycle become key competitive areas for enterprises. In industrial and commercial scenarios, the predominant applications often involve off-grid power supply, light-storage-diesel microgrids, and weak grid applications, intensifying the demand for grid-building technologies.
Sungrow has pioneered user-side grid-building technology that actively manages unbalanced loads and sudden voltage/frequency fluctuations, ensuring stable power supply and avoiding critical load outages. Its self-developed three-phase four-wire PCS supports 100% unbalanced loads, operates off-grid, and is resilient against power outages, capable of megawatt-level black starts for parks.
In addition to reliable power supply, safety is of utmost importance. The PowerStack 255CS is equipped with an AI health management system for battery cells that can identify and alert abnormal cells seven days in advance. With the industry’s first ArcDefender™ technology for DC arc detection, this product achieves 100% accuracy in identifying arcs and can shut them down in just 0.2 seconds. Furthermore, its fire safety configurations exceed the highest global safety standards. Last year, Sungrow conducted large-scale non-propagation tests, successfully demonstrating the excellent fire resistance and thermal insulation capabilities of its energy storage products.
From “all-weather system comprehensive efficiency” to “user-side grid-building technology,” Sungrow is empowering the entire lifecycle of industrial and commercial energy storage from multiple perspectives including efficiency, returns, safety, and maintenance. As March arrives with its transitional weather, Sungrow, through its leading technology and innovative concepts, is setting new benchmarks for the energy storage industry and promoting the healthy and high-quality development of the renewable energy sector.
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