Battery Energy Storage Systems (BESS) are the most common type of ESS in which batteries are pre-assembled into multiple modules.BESS are available in different sizes depending on their application and their use is expected to increase significantly in the coming years. Although different types of batteries can be used in BESS, lithium-ion batteries seem to be the most popular. Therefore, our focus in this paper is on energy storage systems equipped with lithium-ion batteries.
Siddharth Mahajan, Senior Head of Loss Prevention, Singapore, highlights that BESS with lithium-ion batteries are classified as dangerous goods under the IMDG Rules. In the IMDG rules, lithium batteries and battery packs have various descriptions and shipping names, depending on their chemical composition and whether they are stand-alone, in equipment, or contained in a vehicle or cargo transport unit. This has created some confusion for shippers on how to properly declare this cargo. We have encountered instances where BESS has been declared as either of the following:
UN 3480 (lithium-ion batteries), or
UN 3481 (lithium-ion batteries contained in equipment or packaged with equipment), or
UN 3536 (lithium-ion batteries installed in a cargo transport unit).
Carriers should also be aware of the applicability of the different Special Provisions (SPs) of the IMDG Code. SP 389 (referring to the internal structure of the battery secured to the cargo transport unit) applies only to UN 3536. similarly, many of the other SPs that apply to UN 3480 and UN 3481 do not apply to UN 3536. some of the changes proposed for UN 3536. For more detailed information, see the "Loading and Tying" section below.
Fire and Explosion Risk
As detailed in this recent Gard article, the potential fire and explosion hazards of lithium-ion batteries have become a "hot topic" in the shipping industry. As a precautionary measure, owners should therefore enquire about the State of Charge (SoC) of the BESS before taking delivery; the SoC has a direct impact on the likelihood of thermal runaway fires, as well as growth and peak heat release rates. This has been highlighted by several industry bodies and regulators, such as EMSA's guidance on AFV transport and AMSA's guidance on the risks associated with the transport of electric vehicles. Therefore, it is recommended that the smallest SoCs be used during transport.
Although most BESSes have built-in battery management and cooling systems, thermal runaway events can still occur. If such an event occurs, most units are designed to be vented from the top. If the BESS is stored in a cargo hold, the cargo space may be filled with large amounts of toxic vapour, the build-up of which could cause a vapour cloud explosion. Ventilation of the space may be difficult and, given the volatility and toxicity of the gas, due care needs to be taken to avoid igniting the vapour cloud. It is recommended that containment measures be taken wherever possible and that expert advice be asked for. Some installations may be equipped with a safety system that allows the crew or shore personnel to monitor the installation and be alerted before a hazardous situation occurs. The crew should be made aware of the toxicity of the vapour released and care should be taken to ensure that the gas does not enter the crew's area.
Storage and securing
For bulk carriers and general cargo ships carrying BESS, the following aspects must be considered:
Tie-downs and cargo tanks: If the ship does not have adequate tie-downs, they will need to be assembled under expert supervision and all such modifications will require the approval of the competent authority.
Structural strength of tank tops and hatch covers: The structural strength of tank tops and hatch covers needs to be verified.
Cargo Securing Manual (CSM): It should be verified that the CSM covers the transport of such cargo. In some cases, modifications to the lashing devices and stowage of such installations may also be required and must be approved by the competent authority.
Approvals: Approvals from the ship's classification society and flag state may also be required. Shipowners are advised to contact their Classification Society and Flag State at the earliest opportunity to better understand the requirements and approval process.
Recommendations
Please make sure that the cargo is loaded according to IMO statutory requirements, the ship's CSM, the CSS Code and the IMDG Code.
The ship's classification society and/or flag state should be contacted to obtain the necessary approvals.
It is recommended that shipowners request information from charterers and shippers regarding special handling instructions, state of charge, type of batteries, built-in safety and clear guidance on emergency response.
It is recommended that a risk-based approach be used in determining the stowage position of BESS, which could also take into account the draft amendments to the IMDG Code (42-24).
Ships may need to be equipped with additional fire safety equipment to detect and respond to fires and explosions. It is also recommended that shipowners and managers provide cargo-specific instruction and emergency response training to crews.
