Recently, the iron-sulfur flow battery system co-developed by ZH Energy , Central South University, and Huaneng Clean Energy Research Institute (Huaneng CLEARI) has successfully passed on-site acceptance and is scheduled to be deployed at Huaneng CLEARI. As a core R&D institution under a central power enterprise, Huaneng CLEARI has long been engaged in the research and development of national energy strategic projects, and its technology selection and demonstration applications serve as an industry benchmark. This first iron-sulfur flow battery system for the power generation side under the cooperation not only demonstrates ZH Energy technological strength but also marks the authoritative recognition of iron-sulfur flow battery technology in the power generation sector, laying a solid foundation for its large-scale promotion.

Technical Adaptability: Sulfur-Iron Flow Battery, Providing an "Optimal Solution" for Power Generation-Side Energy Storage

Energy storage on the power generation side needs to meet the triple requirements of high reliability, long-duration regulation, and economic efficiency simultaneously. The three core characteristics of ZH Energy sulfur-iron flow battery precisely match these needs:

• Grid-Level Safety Standard: Aqueous electrolyte poses no combustion or explosion risk, and the all-liquid system avoids phase change hazards. It can adapt to complex environments such as high temperature and high humidity without a cooling system, eliminating safety hazards from the source.

• Long-Duration Regulation Capability: Supports continuous discharge for 4–12 hours, effectively smoothing intra-day fluctuations of wind/solar power, solving the "curtailment of wind and solar power" problem on the power generation side, and improving the utilization rate of renewable energy.

• Whole-Life-Cycle Economic Efficiency: The electrolyte is mainly composed of bulk chemical raw materials such as sulfur and iron, with a cost only 1/10 of that of vanadium flow batteries; the system has a cycle life of more than 15,000 times, and the levelized cost of electricity (LCOE) is as low as 0.1 CNY/kWh, significantly reducing the energy storage burden for power generation enterprises.

Scenario Depth: From Demonstration to Large-Scale, Supporting Grid-Scale Energy Storage Applications

With the continuous increase in the penetration rate of new energy, the demand for large-scale and long-duration energy storage (LDES) in power grids is becoming increasingly urgent. Relying on the following advantages, sulfur-iron flow batteries have become an ideal choice for grid-scale energy storage:

• Power/Capacity Decoupling Design: The energy storage duration can be flexibly extended by adding electrolyte storage tanks, easily achieving hundred-megawatt-hour-level capacity configuration, which is suitable for large-scale needs on the power generation side.

• Efficient Grid Interaction: The electrochemical reaction has a fast response speed, and the charge-discharge conversion can be as low as milliseconds, which can be involved in multiple scenarios such as peak shaving and frequency regulation, improving the flexible regulation capability of the power grid.

• Environmental Friendliness and Resource Sustainability: Neutral electrolyte has no pollution risk, and the main raw materials sulfur and iron have abundant reserves, avoiding dependence on scarce resources such as vanadium and lithium.

Strategic Synergy: Joining Hands with CSOEs to Build a "New Energy + LDES" New Pattern

Relying on the industry influence of HUANENG Clean Energy Institute, this project strongly echoes the previously commissioned sulfur-iron flow battery verification project of the State Grid, and will jointly verify the technical feasibility and engineering reliability of sulfur-iron flow batteries in large-scale energy storage on the power generation side and power grid side. With its advantages of long-duration energy storage, intrinsic safety, and low cost, sulfur-iron flow batteries are expected to become the standard technology for energy storage on the power generation side and power grid side, helping to build a "New Energy + LDES" new power system.

ZH Energy will continue to take "Innovating Long-Duration Energy Storage, Focusing on Energy Security" as its mission, accelerate the industrialization of sulfur-iron flow battery technology, and help China's technology lead the global energy transition.