From a technical standpoint, lithium-ion battery storage continues to dominate the market with a share of 96.1%, serving as the leading technology for new energy storage today. Meanwhile, long-duration storage technologies represented by flow batteries are accelerating their industrialization. As large-scale projects are being deployed and supply chains gradually mature, system costs continue to decline, highlighting their growing value in long-term peak-shaving applications.

As a key technological direction within the long-duration storage sector, flow batteries are particularly well-suited for medium- to long-duration storage scenarios lasting four hours or more. This technology features decoupling between power and capacity—power output is determined by the stack, while storage capacity can be expanded simply by increasing the volume of electrolyte—making it ideal for constructing large-scale, high-capacity grid-side storage stations. Statistics show that by the end of 2025, China's cumulative installed capacity of flow battery storage reached 1.235 million kW/5.141 million kWh, accounting for 0.9% of total new energy storage capacity. It ranks second only to lithium-ion batteries and slightly exceeds compressed air storage, establishing itself as a significant branch within the long-duration storage landscape.

The deployment of numerous large-scale projects with capacities exceeding 100 megawatts has become a core driver behind cost reductions for flow batteries. In recent years, multiple gigawatt-scale vanadium redox flow battery projects have been completed and commissioned across China, demonstrating clear economies of scale. In June 2026, the Jimsar Vanadium Redox Flow Battery Storage Station in Xinjiang officially began commercial operation, with a rated power of 200 MW and a storage capacity of 1,000 MWh—the largest such project currently built in China—providing valuable practical experience for large-scale engineering implementation of flow batteries.

Currently, the system cost of vanadium redox flow batteries remains relatively high, at approximately 2 yuan per watt-hour in 2026—about four times that of lithium-ion battery systems. However, the downward trend is evident. Industry forecasts suggest that over the next two to three years, as the supply chain matures, the system cost of vanadium redox flow batteries could drop to around 1.5 yuan per watt-hour, reaching a critical threshold for cost parity.

Electrolyte and stacks constitute the primary cost components of flow battery systems, and cost reduction efforts primarily focus on these two core elements, aiming to improve current density in stacks and electrolyte utilization efficiency. Presently, the industry average current density of flow battery stacks is about 180 mA/cm², with electrolyte utilization at just 65%. Experts believe that if material and process bottlenecks can be overcome to further enhance these two key metrics, substantial cost reduction potential still exists for flow battery systems.

Domestic regions are also fostering favorable market conditions for long-duration storage through innovative capacity pricing mechanisms. Some provinces now incorporate discharge duration into their capacity pricing calculations, rewarding longer full-power discharges with higher capacity-based revenue. For example, in Shaanxi Province, the capacity tariff for independent new energy storage on the grid side is calculated based on peak capacity, using a conversion factor equal to the ratio of continuous full-power discharge time to the longest annual net load peak duration in the Shaanxi grid (currently set at six hours), capped at 1. Similarly, Gansu and Qinghai link storage capacity returns directly to full-power discharge duration, continuously favoring long-duration technologies like flow batteries.

Regionally, long-duration storage exhibits distinct geographical differentiation. According to the report, in the northwest region, installations for four hours or more already account for over half of all long-duration storage capacity, surpassing the scale of 2–4 hour storage. In contrast, most other regions across the country still rely predominantly on 2–4 hour storage solutions.

Nationally, the average discharge duration of new energy storage systems continues to rise steadily. In 2025, the average discharge duration of new energy storage in China reached 2.58 hours—an increase of 0.3 hours compared to 2024—clearly indicating a shift toward longer-duration storage. In terms of duration-based structure, by the end of 2025, the installed capacity share of 2–4 hour energy storage power stations reached 65.6%, down 5.5 percentage points year-on-year; while the share of new energy storage systems with four hours or more duration rose to 27.5%, a significant increase of 12.1 percentage points compared to the previous year. It is evident that, as pressure to accommodate renewable energy grows and long-duration storage policies continue to improve, long-duration storage systems exceeding four hours are rapidly capturing market share, creating a rare development opportunity for technologies such as flow batteries. Please provide the text you would like translated.