Energy Safe Victoria (ESV) has concluded the Victorian Big Battery (VBB) fire most likely resulted after a cooling system leak caused a short circuit in an electrical component in a Tesla Megapack.
The independent energy safety regulator delivered its findings following an almost two-month investigation into the late July fire at the Victorian Big Battery site at Moorabool. ESV conducted extensive investigations at the site while analysing data from site owner Neoen and its contractors UGL and Tesla, which operate the site.
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After extensive enquiries, ESV found a Megapack cooling system leak caused a short circuit resulting in overheating that led to a fire in a nearby battery compartment, which consequently damaged two Megapacks.
There were further contributory factors with the Megapack in question being switched into an off-line service mode, resulting in the protection systems being inactive.
A 24-hour delay in connecting the batteries to the supervisory control and data acquisition (SCADA) system also meant there was no active monitoring of the Megapack alarms.
ESV has required the site’s owners and operators to implement a number of additional safety measures, which have been put in place, including
- Megapack cooling systems are fully pressure tested when installed on site.
- Megapack cooling systems are inspected for leaks after testing.
- Shorter connection times to the SCADA system to help alert Tesla with specific alarms.
- A new battery module isolation loss alarm has been added.
- Procedure changes for Megapack protection systems.
ESV is satisfied the Victorian Big Battery site can safely re-commence commissioning on September 29, as these changes have been made. Further work needs to take place to ensure the Megapacks are engineered to fully mitigate the risk of fire spread from one unit to another under Victorian conditions.
ESV will continue its investigation to determine whether there have been any breaches of the Electricity Safety Act 1998 that require further action.
ESV Commissioner and chairperson Marnie Williams said, “Safety is crucial in the delivery of the 300MW Victorian Big Battery storage project, which will store reserve power for Victoria.
“The implementation of our recommendations will improve safety at the Victorian Big Battery site. Now that they have been implemented we are satisfied commissioning can re-commence.
“As the state’s independent energy safety regulator we are committed to ensuring all forms of renewable energy are safe and reliable for all Victorians.”
Neoen and Tesla are continuing to work towards delivering the project in time for the Australian summer.
The Victorian Big Battery will unlock up to 250MW of additional peak capacity on the existing Victoria to New South Wales Interconnector (VNI) over the next decade, playing a key role in the transition of the electricity sector towards lower emissions.
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Neoen Australia managing director Louis de Sambucy said, “Safety is our first priority. We have taken the time to understand the cause of the incident and we have implemented actions to ensure it will not happen again.
“We would like to thank the Country Fire Association and the regulatory authorities for their thorough investigations. We are now actively working with all stakeholders to complete commissioning and testing of the project and we look forward to sharing the lessons learnt with the industry in coming weeks.”
The Statement of Technical Findings is located on ESV’s Electrical incident and technical investigation reports page.
