- Tesla and Neoen plan to resume testing of a large energy storage system in Victoria, Australia, on Wednesday after a fire in July slowed their progress.
- Australian authorities required Neoen and Tesla to suspend some operations so investigations could be completed.
- Neoen is sharing results of the companies' root cause analysis, and says Tesla improved the safety of their utility-scale, lithium ion battery energy storage systems.
Victoria's safety regulator for electricity, gas and pipelines has granted Neoen and Tesla permission for "re-energisation testing of the Victorian Big Battery," Neoen said in an emailed statement on Monday.
The Victorian Big Battery is owned and operated by Neoen and is one of the world's largest energy storage systems. It's intended to help avoid blackouts in the region and power homes using electricity from renewable power sources like solar and wind.
Neoen, which is based in Paris, developed the site with partners including Tesla Energy and AusNet with some construction by Cimic Group's UGL. Tesla has not disclosed its suppliers for the project or what types of battery cells it used in the Megapacks, which are lithium ion battery-based storage systems.
Tesla did not immediately respond to a request for comment.
The fire at the battery site in Geelong, Victoria, took place on July 30. Two Tesla Megapacks erupted into flames at the 300 megawatt (450 megawatt hours) facility. No injuries were reported, but the fire triggered a toxic air alert to surrounding neighborhoods.
About 150 fire fighters from the Country Fire Authority and local Fire Rescue Victoria were called on to fight the fire, along with dozens of fire trucks and support vehicles and drones for monitoring temperatures of the two Tesla Megapacks effected. Flames did not spread to any of the other Megapacks among 210 or so that make up the system.
By Aug. 1, two days after the eruption, fire fighters stopped using water on site. The facility was declared under control on the afternoon of Aug 2.
The Country Fire Authority, WorkSafe Victoria, Energy Safe Victoria, and the Environment Protection Authority then required Neoen and Tesla to suspend some operations in Geelong so they could complete parallel investigations.
Neoen expects the results of a full, independent investigation — conducted by Energy Safety Response Group and Fisher Engineering — to be released to the public in November.
"The cause of the fire was identified as coinciding short circuits in two particular locations likely initiated by a coolant leak external to the battery compartment," the spokesperson said. "These occurred while the Megapack was off-line in a service mode that removed fault protections. Enabled by this unlikely sequence of events the fault was able to go undetected and initiate a fire in the adjacent battery compartment."
Neoen also said that Tesla has taken "mitigating actions" after the companies conducted a root cause analysis and added that Tesla is implementing changes to its Megapack firmware and monitoring
The system should be switched back on for testing starting Sept. 29, in preparation for commercial operation of the utility-scale battery by the start of Australia's summer season in December.
Neoen and Tesla are under pressure to satisfy regulators in Australia for their joint work at a separate location. Last week, the Australian Energy Regulator (AER) sued Neoen saying another Tesla big battery it developed, the Hornsdale Power Reserve, did not provide backup power as expected during a four-month period in 2019 for which it had been paid.