Client corner: Battery-powered ships FAQ

Why integrate batteries onboard a ship?

Ship owners and managers are integrating batteries onboard primarily in their effort to limit their greenhouse gas (GHG) emissions. This is being done to support the general decarbonization of the shipping industry, as well as meet local, national and international regulations for shipping sustainability. Batteries are a good option for ships traveling in environmentally controlled areas or operating near heavily populated areas, which are frequently subject to such restrictions. 

What functions can batteries serve onboard?

Batteries most frequently serve as backup power onboard ships, supporting a vessel’s operating profile and maintaining Dynamic Positioning (DP) systems. Depending on battery type, they can function as the only source of electricity for short periods of time. This enables ships to run in zero emissions mode—producing no GHG or carbon. Additionally, batteries can take over from onboard generator sets to deliver peak loads of energy, a practice known as “peak shaving.”

What types of batteries can be integrated onboard?

Lead batteries are the traditional batteries used to provide back-up power to ships. Vented Lead Acid Batteries and Valve Regulated Lead Acid Batteries are both examples of lead batteries that can be installed onboard. They are reliable and recyclable, require fairly low CAPEX investment, and can function onboard all types of vessels.

Lithium-ion batteries are the latest evolution of battery power, encompassing a number of battery types, including lithium iron phosphate, lithium titanium oxide, and lithium manganese oxide. While lithium-ion batteries vary in terms of power density, energy density and lifecycle, they can perform multiple functions onboard.

What is the key risk for battery-powered ships?

The key risk for battery-powered ships is managing “thermal runaway.” This occurs when a battery is subject to high temperatures from a high current discharge rate or external heat sources. This can cause batteries to emit heat, flames and gas, starting a large-scale conflagration that can damage the ships and threaten crewmembers.  

How can ships manage thermal runaway?

To minimize the chances of thermal runaway, industry rules and standards are used to test batteries both during and after manufacturing and onboard integration. Battery manufacturers must also apply additional safety measures like Battery Management Systems (BMS), which monitor the voltage, current and temperature of battery modules, packs and sub-packs. BMS also control the connection and disconnection of battery packs and sub-packs, limiting the potential for a chain reaction in the case of thermal runaway.

What services for battery-powered ships does Bureau Veritas offer?

Our dedicated in-house experts provide expertise for all types of batteries and battery-powered ships. We provide critical safety testing and risk analysis for batteries, offering a standardized approach to risk management for classed and non-classed vessels. Our experts have also created a regulatory framework for battery-powered ships, based on rules that are updated every six months to reflect the latest technical and safety developments.

What notations does Bureau Veritas offer for battery-powered ships? 

Bureau Veritas currently offers three notations for battery-powered vessels:

• BATTERY SYSTEM for the safe installation and use of batteries for propulsion
• ELECTRIC HYBRID for ships using a combination of diesel engines and batteries
• ELECTRIC HYBRID PREPARED for ships designed to have batteries installed later on

Photo Credit: Saft Batteries