According to the International Maritime Dangerous Goods Code (IMDG Code), BESS is classified as Class 9 hazardous goods, with the United Nations number UN3536.
Are energy storage systems dangerous?
In general, energy that is stored has the potential for release in an uncontrolled manner, potentially endangering equipment, the environment, or people. All energy storage systems have hazards. Some hazards are easily mitigated to reduce risk, and others require more dedicated planning and execution to maintain safety.
2. As a consequence, energy storage devices are sometimes not accepted for transport in cases where the containers are not cargo transport units (CTUs) within the meaning of the CSC convention but where the container serves as a sort of battery casing and is no longer used as a multimodal freight container.
12. March 2025 In recent years, demand for the maritime transportation of containerised Battery Energy Storage Systems (BESS) has grown significantly. However, due to the high safety risks associated with energy storage containers, their transportation poses new challenges to maritime safety.
Are new energy storage systems safe?
Interest in storage safety considerations is substantially increasing, yet newer system designs can be quite different than prior versions in terms of risk mitigation. An uncontrolled release of energy is an inevitable and dangerous possibility with storing energy in any form.
Except for vehicles driven by lithium batteries (pure electric or hybrid), containers containing lithium battery hazardous goods must have Class 9 hazardous goods labels and UN number markings affixed to each side and each end of the container (for lithium-ion battery energy storage systems, on two opposite sides).
Resulting primary hazards may include fire, chemical, crush, electrical, and thermal. Secondary hazards may include health and environmental. EPRI's energy storage safety research is focused in three areas, or future states, defined in the Energy Storage Roadmap: Vision for 2025.