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.
BESS refers to a mobile power supply device with lithium battery packs, lithium-ion battery packs, or lithium-metal battery packs installed and secured within specially designed container transport components. According to the International Maritime Dangerous Goods Code (IMDG Code), BESS is classified as Class 9 hazardous goods, with the United Nations number UN3536.
The maritime transportation of BESS primarily involves the following risks:
Lithium battery safety risks
Lithium batteries, as the core component of energy storage systems, are characterized by high energy density and power output. However, their safety directly determines the overall safety of the energy storage system. Thermal runaway is the primary cause of lithium battery fires, which can be triggered by external factors (such as collision, compression, overcharging, over-discharging, external short circuits, or exposure to high temperatures) or internal factors (such as design defects or manufacturing flaws).
Overweight risks
Due to the large size and mass of energy storage systems, individual units usually weigh over 30 tons. They face higher risks of dropping, impact and vibration during loading, unloading, and transportation. These situations may lead to deformation or damage of the container and cause the internal lithium battery to be squeezed by collision, increasing the risk of thermal runaway.
Fire safety risks
Lithium battery fires differ from traditional fires, with high combustion temperatures, difficult to extinguish, easy to reignite, and rapid spread. Lithium batteries can even burn continuously without an oxygen supply or visible flames, complicating fire control efforts.
Transportation environmental risks
The safety of maritime transportation for BESS is affected by multiple factors, including the reliability of lashing and securing, ship tilting and vibration, battery short circuits or overcharging, personnel operation standardization, and meteorological and sea conditions during navigation.
Currently, the maritime transportation of BESS must comply with the relevant regulations of the IMDG Code. However, the requirements are relatively broad, leaving some potential hazards unaddressed. This article has briefly outlined the risks associated with the maritime transportation of BESS aiming to provide a risk warning to relevant practitioners so they can take proactive measures to ensure the safe and efficient transportation of these energy systems.
