New report on management of large-scale battery hazards

It seems each week there is an announcement about a new large-scale Battery Energy Storage System (BESS) being built somewhere in Australia. AEMO’s Generation information page lists existing and announced projects of over 36GW for the NEM alone.

While many competitive and monopoly ownership structures are emerging, it is becoming clear that every integrated energy business is going to require some BESS in its portfolio to remain competitive, and in time AEC members will operate the bulk of Australia’s BESS capacity, which will become a key part their core business operations.

The energy industry places the management of the Health, Safety and Environmental (HSE) hazards of its assets at the highest of its priorities. Consistent with that, the AEC has always supported information sharing and working groups for the HSE managers of conventional generation which are potentially very hazardous sites.

The industry’s transition is naturally seeing these experienced HSE managers turning their focus to managing a large-scale BESS facility. Like conventional generation, these sites pose various hazards, but with appropriate expertise, tools and focus, these risks can be adequately managed.

However, the nature of the hazards of a large-scale BESS are different to that of a conventional plant, and so consequently require new expertise. This is compounded by a rapidly developing technology space in which Australian HSE regulators and emergency services are also gaining experience.

Following a request from its working groups, the AEC is pleased to publish a report prepared by GHD Engineering Consultants about the risks of evolving BESS technologies. The report is intended to serve as a preliminary guide to assist the understanding and management of BESS technology. GHD developed the report using their knowledge, a literature search of incidents and safety standards, and a series of interviews with regulators and emergency services experts.

Batteries ain’t Batteries

Not only are some risks unique from traditional generation risks, there are varying levels of risks between the different forms of BESS technology presently available. Within the dominant Lithium-Ion technology different chemistries are rapidly evolving, with significantly different fire risks between them.

The more exotic battery types, Vanadium redox and Sodium ion, which are being demonstrated in grid scale applications overseas but expected to soon move into the Australian market, likely have lower fire risks.

Thermal Runaway

While not the only hazard, “thermal runaway” is the most often discussed form of BESS failure. Thermal runaway is a scenario where a battery effectively combusts internally without an externally visible cause. Unlike a normal fire that consumes oxygen – which can be starved by a suppressant such as water – a thermal runaway releases great heat simply through the uncontrolled reactions of the chemicals within the BESS.

GHD provides a summary of some major international thermal runaway events and lessons from them, including the Victorian Big Battery incident on 30 July 2021.

Risk Register

After discussing the many forms of HSE risks that must be managed in a large-scale BESS site, GHD provide a “risk register”, a preliminary set of risks to consider when designing and operating a site.

Consistent with standard HSE approaches, this register includes prioritisation based on risk probability and consequence. It then proposes control measures against them.

Findings

A large-scale BESS site has risks, but with appropriate safety assessment processes, expertise and priority, these risks can be managed.

Expertise is an understandable challenge with a new and changing technology. Expertise is also of concern with respect to regulatory authorities and emergency management authorities.

Guidance material is being developed but varies between regions. The Australian industry would benefit from a single, comprehensive, and consistently maintained source of guidance.

GHD and other stakeholders involved in this engagement noted some limitations and benefits of the relevant standard, UL9540A. This was developed overseas and may not simulate conditions which are representative of the conditions within Australia and also within the proposed facility itself.

GHD noted that the standards and regulatory frameworks need to adapt to keep up with the advances in the technology. It is in the industry’s interest, as buyers of that technology, to increase their efforts to ensure these frameworks are effective in achieving key approvals and acceptable levels of safety.

GHD have proposed a high-level guide for assessment of BESS facilities moving forward, and it is anticipated that stakeholders will review and over time refine this advice.

The AEC thanks GHD for bringing together this report.