(Bloomberg) — The explosion ruptured the dusk settling over the desert in Surprise, Arizona. For hours, the smoke had poured from a metal shed packed with lithium-ion batteries at a small electric substation. The batteries were tied to the electric grid, and somehow they had caught fire.
Firefighters searching for the source of the smoke opened the shed door, and minutes later gases seeping from damaged batteries caused the explosion. Body-camera footage from the scene showed a firefighter dazed and breathing heavily as blood ran down his forehead. Two of the four people injured had to be airlifted to a hospital.
It’s likely that few people living near the substation, on the edge of suburban Phoenix, realized the facility held the kind of supersized batteries seen as key to unleashing renewable energy upon power grids and helping solve the climate change crisis.
Plunging prices and intensifying efforts to reduce greenhouse-gas emissions have touched off a battery boom. Energy companies are plugging more battery packs into the grid as a way to store renewable power and replace fossil-fuel plants. Megaprojects are becoming the norm. Last year, regulators approved a battery installation in New York City that will be big enough to power 250,000 homes for eight hours. Developers near Las Vegas plan a similarly huge system to store energy from a 690-megawatt solar plant.
But the April explosion in Arizona illustrated a lingering problem that has long dogged lithium-ion batteries: fires that can be difficult to douse. In South Korea, a global leader in battery manufacturing and adoption, there have been at least 23 fires over a roughly two-year period, according to BloombergNEF, spooking customers and prompting a government investigation.
In little more than a decade, the rechargeable batteries invented in the 1970s have become a cornerstone technology of 21st-century life. They are seldom far from any of us, powering toothbrushes and smartphones, toys and earbuds, laptops, and Teslas. Global production is expected to triple within the next three years, according to BloombergNEF.
If lithium-ion batteries started as consumer convenience, now they have emerged as an indispensable tool to combat global warming. Electric utilities need a way to soak up solar energy during the day for use after dark and bottle the output of wind farms for when breezes fade. Automakers are rolling out a fast-growing fleet of electric vehicles—not just cars, but pickups, buses, and big rigs—to clean up transportation, the source of nearly a quarter of the world’s greenhouse-gas emissions. The battery’s moment has arrived.
But rapidly swelling numbers will likely bring more battery fires. The incidents remain rare compared to the volume of batteries, but experts expect a surge as the technology becomes ever more inescapable.
“If the percentage of failures holds, that could mean a lot of problems,” said Mike Simpson, senior technical leader at the Electric Power Research Institute. “Even a one-in-10 million likelihood of failure on the assembly line could still lead to many failures on the road.”
Fear of fires isn’t killing global battery demand, which BloombergNEF predicts will grow more than seven-fold by the end of the decade. But the incidents have, at times, shaken public confidence. South Korea, the world’s third-largest battery maker, went on an installation binge of utility-scale batteries until a string of nearly two dozen fires prompted a backlash and government probe. In the end, the investigation blamed many of the fires on sloppy installation and operational errors.
“This is early growing pains for new technology and a new industry,” said Daniel Kammen, chair of the Energy & Resources Group at the University of California at Berkeley. “We didn’t even have grid-scale batteries a few years ago.”
Some fires can be traced to manufacturing defects in the battery cells themselves or physical damage after installation. Overcharging can also be a problem, Simpson said, as can poor integration with other electrical systems.
Each of those factors can tip a battery cell into a dangerous, uncontrolled chain reaction known as thermal runaway. The flammable electrolyte inside the cell suddenly heats up and causes the same thing to happen in adjacent cells. Once ignited, the batteries can emit toxic fumes.