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A fire at one of the largest Tesla battery installations in the world has drawn fresh attention to the risks of batteries used to store renewable energy for electricity grids.
It took three days for the blaze to be extinguished after it started during testing in a shipping container holding a 13 tonne lithium-ion battery, at Moorabool near Geelong in Australia, and spread to a second battery pack.
The “Victorian Big Battery” project using the Tesla Megapack is the largest in the country, with 210 packs capable of storing up to 450 megawatt-hours of energy for the electricity grid.
Owned and operated by the French renewable energy developer Neoen, it was scheduled to begin operating before the peak summer demand period this year. Neoen said it was too soon to tell how the commission would be affected and testing would resume only once safety conditions were met.
The incident comes as utilities around the world from Australia to California increasingly rely on large lithium-ion batteries to store renewable energy from the wind and the sun. The same type of batteries as those used in electric cars, they can deliver power quickly to the electricity grid.
The amount of energy storage deployed last year rose 62 per cent, according to consultancy Wood Mackenzie, and the market is set to grow 27-fold by the end of the decade.
Yet there have been a total of 38 large lithium-ion battery fires since 2018, according to Paul Christensen, a professor at Newcastle University.
In Beijing, a fire at a lithium-ion battery installation in April killed two firefighters and took 235 firefighters to control. Last September, a large lithium-ion battery in Liverpool, owned by Danish renewable energy company Orsted, caught fire in the middle of the night.
Lithium-ion batteries can catch fire after a process called “thermal runaway”, which results when a battery is overcharged or crushed. Heat as well as a mixture of gases are produced, which when released form a vapour cloud that can ignite or cause an explosion.
In 2019 in Arizona, a grid-scale lithium battery fire threw a firefighter more than 20 metres from the container door, leaving him with a brain injury and broken ribs. That fire started after a short circuit in one lithium-ion battery cell, according to a report released after the incident.
Because of the release of gases “we don’t have a definitive answer of what is the best way to deal with an EV [electric vehicle] fire or energy storage fire,” Christensen said.
“They [lithium-ion batteries] are essential to the decarbonisation of this planet but their penetration into society has far outstripped our actual knowledge of the risks and hazards associated with them,” he said.
The risks will only increase as individual households increasingly install lithium-ion batteries to store energy from solar panels, or to reduce reliance on electricity grids following a spate of extreme weather events, he said.
In Australia, fire crews wore breathing apparatus and hazmat suits as they attempted to contain the flames, Fire Rescue Victoria said. Drones were also deployed.
Matt Deadman, lead officer for alternative fuels and energy systems at the National Fire Chiefs Council in the UK, said lithium-ion battery fires burn for much longer than usual fires and water only reduces their spread.
“It’s about cooling the batteries and you can extinguish the flame but lithium-ion batteries will produce their own oxygen as they break down — they will keep catching fire again, we just take as much as heat as we can out of them,” he said.
“At the moment we rely on tried and tested firefighting methods using water which is effective but it’s not a golden bullet for solving these things as quickly as you possibly can,” Deadman said.
Tesla said last month revenues from its energy storage and generation business, which includes sales of its Megapack batteries, more than doubled in the latest quarter to $801m.
Elon Musk, Tesla’s chief executive, said safer variants of lithium-ion technology such as lithium-iron phosphate batteries — which use iron and phosphate instead of the metals nickel and cobalt — are suitable for its large battery installations.
Gavin Harper, a research fellow at the University of Birmingham, said: “It is essential that we don’t stifle new innovation as it is imperative that we decarbonise rapidly, but at the same time, we need to take a precautionary approach as we deploy new technologies at scale.”
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