The hazards of electric vehicles

EV AT SEA

BATTERIES • RAPID GROWTH IN THE USE OF ELECTRIC VEHICLES IS RAISING NEW SAFETY CONCERNS, PARTICULARLY DURING THEIR TRANSPORT BY SEA, AS THE UK P&I CLUB HIGHLIGHTS

IT IS QUITE LIKELY that anyone reading HCB knows that lithium cells and batteries – both lithium ion and lithium metal – are treated as dangerous goods for transport purposes. That goes equally for those contained in equipment (or packed with equipment) and for the batteries shipped alone. There have been numerous fires involving lithium batteries being transported by all modes, which are of particular concern in the aviation sector but are also a problem for maritime and road transport.

The recent rapid growth in the manufacture and use of electric vehicles has added to the list of hazards, during the transport of new vehicles from production plants as well as during the return of damaged or defective batteries, not least since the batteries are generally quite large. However, as yet the amount of realistic data about the potential fire risk of electric vehicles is limited. To try and gather more information, the UK Maritime & Coastguard Agency (MCA) issued a consultation document this past October on a draft Marine Guidance Note (MGN 653(M)) on the transport of electric vehicles on passenger ro-ro (ro-pax) ferries; but the problem also presents itself in the specialised car carrier market.

The UK P&I Club is also trying to raise awareness of the potential hazards, since it realises that regulations can be slow to respond to rapid changes in the nature of the shipping market and emerging hazards; the Club says the onus will be on the maritime industry to develop new operating procedures and on crews to use those procedures to mitigate the risks. Many vessel operators are already taking a cautious approach to the carriage of electric vehicles and those powered by alternative fuels.

A RANGE OF RISK It is not that electric vehicles are inherently unsafe; does a car with a large battery represent more of a risk than a car with a tank full of flammable liquid? The UK P&I Club says, though, that new technology always carries with it the potential for unintended consequences and it is important for every stakeholder to understand the risks to mitigate them effectively. There are also different types of new technology: there are ‘pure’ electric vehicles (EVs) that are fitted with rechargeable batteries and have to be charged from an external power source; plug-in hybrid electric vehicles (PHEVs) have a smaller battery but also a conventional engine powered by gasoline or diesel; and hydrogen fuel cell electric vehicles have no battery, instead generating power from hydrogen.

In recent years, the technology applied to electric vehicles has advanced remarkably quickly and will likely continue to do so, in a search for longer driving range and smaller batteries. This creates challenges in terms of battery manufacturing quality, the Club states.

The main hazard posed by a rechargeable lithium battery is that, if it catches fire, it can result in temperatures of 1,000°C or more; it can also release toxic gases. Such a fire on the cargo deck of a ro-ro vessel or on a car carrier could spread rapidly, posing risks to the vessel, the crew and the environment. Such a fire could be initiated by the battery itself, either due to damage or faulty charging, leading to thermal runaway; a fire might start elsewhere and spread to the battery; or in the case of a fuel cell, there could be an explosion due to the release of hydrogen resulting from damage or fire engulfment.

The UK P&I Club notes that the safety of charging electric vehicles aboard ships has not been widely discussed but, as it is an area on which MCA is currently consulting, if clearly needs to be considered.

WHAT’S TO BE DONE Pending the introduction of specific regulation or industry standards, the UK P&I Club has offered some ideas for operational changes that could be made to minimise the risks involved in the transport of electric vehicles aboard ships. It is important that the crew understand the risks the vehicles present and be provided with appropriate personal protective equipment. It is also important for the crew to know where such vehicles are located; they should be clearly marked on the stowage plan so that, in the event of an incident, emergency responders can act appropriately. Training and equipment for rescue workers may need to be adapted, the Club suggests.

Existing sprinkler systems are unlikely to be effective against a fire involving an electric vehicle; these fire suppression systems typically shower water from the deckhead down, whereas batteries are usually located close to the floor of the car. High pressure water mist systems seem to be particularly suitable due to their inerting and cooling effect, so these systems are preferable for battery fires. Furthermore, cooling a battery on fire requires large quantities of water. Thus, to avoid endangering the stability of the ship, it is important to ensure that extinguishing water can run off unhindered, while keeping it free from burnt material and cargo.

Watch-keeping and fire rounds are essential to keep a close eye on damaged cars, coolant leakages, indications of heat, and venting. Use of thermal imaging scanners by the cargo watch-keepers is suggested, and some vessels are provided with CCTV cameras for monitoring which can lead to early detection.

A quick muster, decision making, and effective teamwork can ensure a fire is under control quickly before it spreads. Electric vehicles should be transported in special areas equipped with appropriate gas and fire detectors, fire extinguishing equipment and fire extinguishing agents. In the case of a fire, the possibility of separating vehicles by means of a water wall or mobile partitions could be explored.

There are particular hazards relating to fuel cell vehicles. The escape of hydrogen on a closed or even semi-open deck can easily lead to an explosive atmosphere and the Club recommends that such cars be transported only on open loading decks. Furthermore, areas where hydrogen could escape must not be protected by a CO2-based fire suppression system, as the CO2 being discharged may ignite hydrogen. It is also important to remember that hydrogen is much lighter than air and, if released, will collect under the deckhead; current explosion protection provisions concentrate on gases that are heavier than air.

According to the UK P&I Club, there are several areas where further investigation is warranted: for instance, what is the ideal state of charge for a battery vehicle being transported; and what is the effectiveness of different combinations of fire detection, gas detection and firefighting installations. As more reliable data emerges, the Club says, more concrete ideas for operational changes may also be developed. However, it warns, existing ro-ro vessels are unlikely to undergo any significant design changes in terms of fire detection or firefighting capability, so operators will need to concentrate on adapting their procedures. www.ukpandi.com

WHILE THE TRANSPORT OF NEW AND USED CARS BY SEA

IS AN ESTABLISHED BUSINESS, THE EMERGENCE OF

BATTERY-POWERED VEHICLES RAISES NEW CONCERNS,