Are electric cars a greater fire risk than petrol or diesel cars? | Car Industry

Uwhen a fire broke out in a car park at Luton Airport last month, it sparked a round of speculation that an electric vehicle was to blame. The theory was quickly quashed by Bedfordshire Fire Service, who said the fire appeared to have been started by a diesel car.

Still, the rumor refused to die down, spreading across social media like, well, wildfire. Even when these stories are patiently debunked, they return as zombie myths that refuse to die.

Electric vehicles (EVs) won’t save the environment from damage, but international climate forecasters agree that they are a crucial part of the transition away from fossil fuels. The Guardian spoke to experts and sought hard data wherever possible to answer some of the most common criticisms of electric vehicles.

In a series of articles, we will highlight the myths, realities and gray areas. The first in our series asks: should we be more worried about fires in electric cars?

The claim

Electric car fire claims fall into two broad categories. The first is that fires are more common with electric cars, while the second is that when fires do occur, they are more damaging.

If electric cars pose a greater fire risk than gasoline or diesel cars, this would have multiple consequences. One could be a requirement for bigger car parks to stop fires spreading, while Conservative MP Greg Smith, who sits on the transport committee, said in July that electric car owners should pay higher insurance premiums , to cover the additional costs of firefighters.

If electric cars pose a greater fire risk, they will need larger parking lots to stop fires from spreading. Photo: Westend61/Getty Images

The science

There are millions of electric cars on the world’s roads, so some data on the spread of fires is emerging, albeit piecemeal. That evidence suggests there’s no reason to think electric cars are more likely to burst into flames, several experts said. Indeed, the opposite appears to be true.

“All the evidence shows that electric cars are much, much less likely to catch fire than their petrol equivalents,” said Colin Walker, head of transport at the Energy and Climate Intelligence Unit think tank. “The many, many fires that you have for petrol or diesel cars simply go unreported.”

Fires can start in several ways. Car batteries store energy by moving lithium ions around inside the battery cell, but if the cells leak, or if impurities from manufacturing errors cause a short circuit, then unwanted chemical reactions can start “thermal runaway”, where the cells heat up quickly, releasing toxic and flammable gas. In gasoline vehicles, fires can start due to electrical faults causing sparks, or if the engine overheats due to a failure in the cooling systems, potentially igniting flammable fuel.

In Norway, which has the world’s highest share of electric car sales, there are between four and five times more fires in petrol and diesel cars, according to the Directorate for Social Security and Emergency Preparedness. This year, the Swedish Civil Contingencies Agency found that there were 3.8 fires per 100,000 electric or hybrid cars in 2022, compared to 68 fires per 100,000 cars when all fuel types are considered. However, the latest figures include arson, making comparisons difficult.

The Australian Department of Defense funded EV FireSafe to investigate the issue. It found that there is a 0.0012% chance of a passenger electric car battery catching fire, compared to a 0.1% chance for cars with an internal combustion engine. (The Home Office said it was unable to provide figures for the UK.)

Elon Musk’s Tesla is the largest manufacturer of electric cars in the world. It said the number of fires on US roads involving Teslas from 2012 to 2021 was 11 times lower per mile than the figure for all cars, the majority of which were petrol or diesel engines.

A red Tesla Model 3 parked and charging on a city street
Tesla Model 3 charging on a city street. Photo: William Barton/Alamy

Any caveats?

The reason for the belief that electric cars are more prone to fires becomes clearer when you watch a video of one: they can be raging infernos.

Paul Christensen, professor of pure and applied electrochemistry at Newcastle University, studies batteries and helps train fire crews. It highlights the ominous risks of “cloud vapor explosions and rocket flames” when the gases burst from the cells.

A woman riding an electric scooter in London
Paul Christensen, a professor at Newcastle University, advises owners of electric scooters not to leave them charging indoors or unattended. Photo: Avpics/Alamy

However, Christensen said the EV’s reputation has been tarnished by their lithium-ion cousins. He has real concerns about electric scooters and bikes that use similar technology, but often from unregulated, inexperienced manufacturers or even DIYers using parts of the internet. (He advises people never to leave scooters charging indoors or unattended.)

There’s also a bit of a conundrum for firefighters, as battery fires require more water to extinguish, can burn nearly three times as hot and are more likely to reignite, according to EV FireSafe. Some fire departments have experimented with fully submerging electric cars in water tanks.

The verdict

Despite the increased danger after a battery fire, the likelihood of being caught in an EV fire seems generally much lower than for petrol or diesel cars, based on the data currently available – although this could change. when more people get electric cars.

Walker said the prevalence of EV fires is likely to increase as the average age of batteries on the road increases. However, at this stage it seems that they would have to multiply many times over to be worse than internal combustion engines.

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