Interislander’s new requirement part of fresh focus on alternatively-fuelled vehicles.

ELECTRIC car drivers conceivably risk missing the boat if a new requirement set by the main ferry provider across Cook Strait is flouted.

KiwiRail says one particular issue causing fiery on-line owner angst, an insistence EVs - plug-in hybrids as well as fully electric types - are not rapid charged prior to Interislander check in, is for good reason.

But it has now also clarified other fresh conditions to reduce the risk posed by EV fires that have raised owner concern shouldn’t, as they aren’t for private motorists.

Requirement to bring an EV on board with less than 30 percent charge and to identify it when booking a fare as a dangerous good “do not apply to passenger vehicles (but) only to large car transporters - ie commercial operators carrying EVs/hybrids as cargo.”

Interislander has also notified it may choose not to transport EVs that have been modified or damaged in a collision.

The risk from EVs catching fire is statistically extremely low, but several carrier ships transporting these vehicles have been lost or significantly damaged by fire.

Exposure to sea water could become an issue for damaged lithium ion batteries - a chemistry increasingly favoured by car makers - as it might kick off a violent chain reaction of chemical reactions called thermal runaway, which results in overheating that generates toxic gases and risk of explosion.

If EV batteries somehow ignite they burn hot, are highly challenging to extinguish and can reignite when exposed to air.

KiwiRail’s stipulations build on measures shared in 2022 and implement in time for the Christmas-New Year break that is often the busiest period for holidaymaker traffic.

Mains-replenished electric vehicles are most likely to be impacted as, while they comprise a modest proportion of all cars and light commercials on the road, their count now exceeds more than 100,000 vehicles, of which more than 70,000 are fully battery reliant.

Rapid charging is a high-power method that uses direct or alternating current to charge an EV as fast as possible. Rapid chargers can replenish to 80 percent in as little as 20 minutes, with provision commonly ranging from 50kW to up to 300kW.

Animated discussion on a popular EV owner Facebook site has been diverse, with some saying they will comply, others that they will rebel and many suggesting KiwiRail’s apparent chief concern, of fire danger, is overblown.

KiwiRail in return says Interislander has a legal obligation under the Health and Safety at Work Act “which requires us to provide the highest reasonable level of protection against harm.”

The KiwiRail spokesman did not say fire was the issue, instead simply offering that: “Interislander recently made improvements to our online booking process, making it much quicker and easier to use.

“As part of the changes, we now collect information on 'alternatively fuelled' vehicles.”

As well as fully and partially - so hybrid and plug-in hybrid - electric cars, that catchment also includes vehicles running on hydrogen - which is just a handful of cars and trucks - liquid petroleum gas or compressed natural gas.

Said the spokesman: “ This allows us to identify how many of these vehicles are travelling with us and to ensure they are loaded in appropriate areas of our ferries.

“We now ask customers who bring a plug-in electric vehicle onboard to avoid using rapid charging for at least two hours before check in.”

Interislander’s competitor, Bluebridge, does not single out EV on its ‘frequently asked questions’ page and operator StraitNZ has not replied to emailed questions about whether it already has, or will implement, the same policies.

Some EV owners say they will simply transfer allegiance to avoid what see as an imposition in respect to their charging habits.

EV charging avails locally in Wellington and Picton; the perceived KiwiRail ideal is that owners replenish their cars after leaving the ship, instead of before embarking.

The international car industry points out that no official crash test has ever caused an EV to catch alight but accepts fires might stem from a fault or crash. Even then, one Swedish study involving 4.4 million cars - of which 611,000 were electric - concluded EV fires are 20 times less likely to happen than internal combustion car fires.

An EV owner querying the policy shared a response from KiwiRail on the owners’ Facebook page.

This acknowledged that internal combustion vehicles also carried a fire risk and “that data supports EVs suffer lesser combustion events.”

Yet it also pointed out key differences in the ways in which the fires burn, including the gasses they release, “which mean they are harder to extinguish and require slightly different approaches.”

The response said Interislander had to consider the unlikely and ‘black swan’ events. That descriptive applies to an extremely negative event or occurrence impossibly difficult to predict.

It also said the reason for targeting rapid charging was on understanding this created an immense amount of energy transferring to the battery in (a) short time.

This meant that “during and just after the rapid charge there is higher possibility of a thermal runaway event (however rare).

“The reason behind the two hour figure before check in opening versus two hours before sailing was effectively chosen to provide a buffer post charge to allow any event to occur away from our vehicle queues and marshalling areas where parking in close proximity and possibly boxed in with other vehicles can make it difficult to evacuate people or move a car that's on fire.”

Interislander also addressed EVs in 2022, saying then that it transported more than 200,000 cars between the North and South Islands every year, and while EVs represented a small percentage of those, it expected that to grow.

It determined then to prohibit recharging of EVs onboard the current ships, an idea it had previously explored, but voiced thought it might be allowed on the new-generation vessels, which were cancelled soon after the National-coalition government took office last year.

It also highlighted then that specialist firefighter equipment on the current ferries expected to maintain an EV fire included drencher systems, CO2 smothering systems, fixed water cannons and water curtains.

Ferry image provided by KiwiRail.