China launches first urban underground vanadium flow battery energy storage project

In what is described as China’s first deployment of its kind, Sichuan Tianfu Energy Storage Technology and Sichuan Chemical Group have launched a 1.25 MW vanadium flow battery (VFB) energy storage system in the basement of a commercial office building.

The project aims to address the growing demand for energy storage in dense urban environments, where safety regulations and space constraints are increasingly limiting the use of conventional battery technologies.

The system is designed to support a 1.1 MW air-conditioning load, ensuring a stable power supply during periods of peak demand and grid restrictions. By charging during low-cost off-peak hours and discharging during daytime peak periods, the system helps reduce electricity costs while maintaining uninterrupted cooling during summer power shortages.

As a non-flammable chemistry, vanadium flow batteries are considered particularly suitable for underground deployments. The technology does not pose high-temperature hazards or emit toxic gases, allowing seamless integration with building safety and fire standards. In addition, thanks to its decoupled energy-and-power architecture, with separated electrolyte tanks and stacks, the system prevents chain reactions even in the event of electrolyte leakage.

The vanadium flow battery also offers strong lifecycle performance, with more than 20,000 charge–discharge cycles and an operational lifespan exceeding 20 years. The installation integrates an intelligent energy management system that enables automated peak shaving, demand response, and remote monitoring.

Its modular design allows the system to be installed in unused basement spaces without affecting parking areas or surrounding green spaces, making it particularly attractive for commercial and urban buildings.

The deployment comes amid tightening safety regulations for electrochemical energy storage systems in China. In February 2026, Hunan Province introduced new rules restricting the installation of lithium-ion and sodium-ion battery systems in underground, semi-underground, rooftop, or densely populated building areas due to thermal runaway risks.

Vanadium flow batteries, however, are not subject to these restrictions because they use non-flammable, water-based electrolytes, making them inherently safer for deployment in sensitive locations such as commercial buildings and underground facilities.