From sea to shore: supporting EV onboard charging with new EVOC notation

From sea to shore: supporting EV onboard charging with new EVOC notation

Jul. 11 2023

Switching to an electric vehicle (EV) is a change that organizations and individuals can make to reduce their carbon footprint. But these consumer choices have an impact on mobility needs, and that includes shipping

Ro-ro passenger ships are transporting increasing numbers of EVs. No cargo is completely without risk, and in the case of EVs, the risk of lithium-ion (Li-ion) battery fires at sea is one that requires rigorous assessment and mitigation measures.

How big is the risk?

Firstly, it must be emphasized that – generally speaking – EV fires are rare and significantly lower in frequency than gasoline or hybrid vehicles. The real risk, however infrequent, lies in the potential devastation of these hard to handle fires. Fires from Li-ion batteries used in EVs can burn hotter and longer than gasoline fires, and can take tens of thousands of liters of water to extinguish. Such fires can be triggered by damaged batteries, collisions, and during the charging of a defective battery.

The likelihood of a ro-ro operator encountering an EV fire at sea is a numbers game – the more EVs transported by sea, the higher the risk. And the numbers of EVs out there is certainly growing. The International Energy Agency (IEA) estimates the total number of EVs on the road in 2021 at 16.5 million, with a further 10 million cars sold in 2022.

Finally, there are the specific characteristics of a ro-ro ship that factor into the risks of EV fires. Ro-ro passenger vessels typically contain a single horizontal fire zone, with cargo left uncontrolled and stowed close together. Additionally, ro-ro vessels are increasing in size and capacity and ro-ro operators are considering offering EV charging facilities to passengers at an additional fee. This last move has raised concern as an increased risk factor.

Introducing our EVOC notation

Bureau Veritas has created an additional class notation – EVOC – to help ro-ro owners and operators offering onboard charging options account for and manage a two-fold risk:

  • Battery thermal runaway, which may result from mechanical or electrical abuses of the battery (i.e., collision, overcharging, fires elsewhere in the ro-ro space) that may lead in turn to the production of flammable or explosive gas mixtures
  • Li-ion battery fires, which are both very challenging to extinguish, and can self-re-ignite

The notation is included in our NR467 Rules for the Classification of Steel Ships, and looks at three main aspects of the charging area: the arrangement onboard, the installation of electrical equipment and fire safety.

To earn the EVOC notation, ships will have to have a dedicated recharging area with appropriate signage and markings, located away from emergency exits. These areas will need to be equipped with fire detection and fighting equipment, such as a water-based fire-fighting system, smoke and heat detectors, thermal cameras or CCTV, as well as 10 air changes per hour (ACH) ventilation.

The electrical equipment used for charging also must meet certain requirements:

  • Charging stations and cables must be type-approved
  • The power balance must avoid any disruption to the ship’s safe operation from the charging stations energy needs
  • Proper communication between the EV’s battery management system and the ship must be established through the charging station

Sharing our safety commitment

At Bureau Veritas, safety is an Absolute. This means that no matter what, we will not compromise on upholding the highest possible standard of safety in all circumstances. As our clients encounter new risks in their operations, we will continue to update our guidance to help them ensure they can sail safely.