In 2024, CSIRO and Energy Networks Australia collaborated to explore the vulnerability of the Australian population to extreme heat, particularly when compounded by power outages. This brief report summarises the key findings of the research project.

CSIRO, Energy Networks Australia

Summary report (December 2024)

A. Bratanova, H. Chen, H. Pham, A. Tursunalieva, S. Dunstall, E. Schleiger and R. Dunne

Why do we need to understand the heat vulnerability of Australians?

Extreme heat significantly impacts human health, infrastructure and the environment. In the 2023-24 summer alone, extreme temperatures affected much of the Australian population, particularly in South Australia, Victoria, and New South Wales. Heatwave conditions were worsened by damaging winds and heavy rainfall, which disrupted energy infrastructure and led to power outages, affecting over 100,000 households and businesses [1].

Heatwaves pose especially severe health risks when combined with power outages. Without electricity, cooling systems fail, leading to dangerously high indoor temperatures. This combination is particularly life-threatening for vulnerable populations such as the elderly, young children, and those with pre-existing health conditions [2-6].

While quantitative data on the compounded effects of heatwaves and power outages are limited, substantial qualitative evidence highlights the severe impact of these concurrent events. This brief report presents a summary of the results of a collaboration between CSIRO and Energy Networks Australia to explore the effects of extreme heat on the Australian population when compounded by power outages. It introduces an approach to comparing the vulnerability of different population groups to heat stress under conditions of loss of electricity supply (LOS).

Source: BOM [7], AIHW [8], Anderson & Bell [9], DCCEEW [10], Brodribb et al [10], BOM [11].

How do we measure heat vulnerability under LOS conditions?

In this research we developed a vulnerability index using three components – exposure, sensitivity, and adaptive capacity (ESA). The ESA model is one of many approaches used by researchers and practitioners to estimate and compare the heat vulnerability of population groups [5, 12-16]. While different models have their own strengths and weaknesses, the ESA model was selected due to its transparency and alignment with the Intergovernmental Panel on Climate Change definition of vulnerability [15, 17-19]. The three key components of the ESA model concerning heat stress in LOS are:

  • Exposure: the degree to which populations are subjected to heat stress.
  • Sensitivity: the extent of adverse reactions to heat stress within the population.
  • Adaptive capacity: the ability of the population to mitigate the effects of exposure and sensitivity through proactive measures.

The vulnerability index is calculated by integrating three components—exposure, sensitivity, and adaptive capacity — to assess the likelihood of adverse human reactions, including severe injury or death, due to heat stress during LOS events. The index incorporates 18 indicators derived from publicly available statistical data across the three components of the ESA model (Figure 1). The model recognises that both environmental exposure and demographic factors significantly influence health outcomes. It is designed to address both immediate stress events, such as heatwaves, and long-term risk assessments.

Figure 1. Heat vulnerability index development. Source: Adopted from Burayidi [20] and Wilhelmi & Hayden [21]

To apply the ESA method and analyse the geographical distribution of heat vulnerability under LOS events, ESA components were mapped to approximately 61,800 Australia’s Statistical Area Level 1 (SA1) regions. SA1s are classified as either urban or rural, with populations typically ranging from 200 to 800 people, with an average of around 400 individuals [22].

The heat vulnerability map of Australia, derived from the ESA model, highlights regions at greater risk in bright green and yellow (Figure 2). Central and inland areas, particularly in Queensland, the Northern Territory, and the northern half of Western Australia, show high vulnerability, due to a combination of high exposure and sensitivity with low adaptability. Among major cities, Melbourne, Perth, and Adelaide generally display lower vulnerability, shown in dark blue, compared with Sydney and Brisbane.

Figure 2. Map of the heat vulnerability index under LOS for Australia.

What can vulnerability tell us?

The ESA model is a robust and transparent analytical tool, but its true effectiveness lies in its integration into existing practices and its ability to enhance decision-making processes. The ESA model can be used at three levels:

  • Strategic – for network investment
  • Tactical – for informing activity towards technological and behavioural interventions at the consumer level
  • Operational – for improved network operations decisions during heatwave events

Scenario planning, a widely applied method for decision-making under uncertainty [23-25], is recommended at the strategic and tactical levels, to support both long-term planning and immediate, localised actions. For scenario planning, we suggest integrating ESA-based vulnerability assessments with electricity network data and climate change models to support long-term planning and risk management.

For tactical decisions, we recommend a threat barrier approach to address immediate risks and set priorities. While at operational level, information systems can overlay ESA, meteorological, and network information to enable prioritisation of those parts of the network that are associated with elevated human health risks.

What can decision makers do to better understand and address heat vulnerability during power outages?

The Australian electricity system faces increasing challenges due to growing demand, supply disruptions, and intensifying heatwaves. This research examines the composition and geographical distribution of heat vulnerability during power outages, uncovering significant variations across the country and the complex interplay between extreme heat events and LOS. By identifying and mapping vulnerable communities, the research informs strategic infrastructure upgrades, resilience measures, and prioritisation of power-restoration efforts to protect public health and strengthen long-term community resilience. The research also underscores that, while quantitative data on the safety consequences of power outages during heatwaves are limited, qualitative evidence indicates significant risks. The following five directions present a summary of key recommendations developed from the CSIRO and ENA collaborative project to address these risks, ranging from easily implemented solutions to those requiring coordinated investments and further research:

  • Enhancing heat-injury risk management by utilising customer data and advanced analytics.
  • Leveraging technology for community resilience through real-time monitoring, early warning systems, and tailored communication.
  • Applying strategic foresight and scenario planning to guide energy investments and policy decisions.
  • Expanding research to include commercial customers for a more comprehensive assessment of heat-related risks.
  • Continuously improving knowledge of population responses and building energy performance through ongoing research.

Practical solutions based on the ESA method should remain adaptable, refining strategies as new data emerges and lessons are learned. This dynamic approach will bolster Australia’s ability to manage extreme heat events and electricity supply challenges, enhancing resilience and safeguarding vulnerable populations.

References

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