Power outages affect individuals, cutting off access to services like lighting, air conditioning, and communication. Here, we draw on our recent paper to explain how power system failures affect individuals, how we can measure the human impacts of outages, and how we can mitigate human harm in our power systems planning.
The human impacts of power outages
Although only a minority of power system failures are directly caused by humans (only about 15% of all major transmission system failures in Europe), power outages can often have tangible impacts on human well-being.
At best, these outages are an inconvenience: not being able to turn the lights on, catch a tram, or turn on a fan can be annoying and unplanned additions to a normal day. However, power outages can also have far more serious impacts (Figure 1). Some electricity consumers are more vulnerable to the effects of power interruptions than others due to age, social isolation, and limited access to services. Underlying health conditions represent a significant concern: power loss can disrupt critical medical equipment, such as ventilators, and having inaccessible cooling & heating services increases the risk of weather-related health problems. Unexpected power loss can also have indirect effects on human health by encouraging people to engage in riskier behaviours, such as seeking to replace typical heating and cooking services with unsafe alternatives, like using a propane stove inside closed spaces. Frequent and long-term power outages also harm the businesses and industries upon which our economies rely.
Figure 1. Overview of causes and impacts of power system failure. Information based on Stankovski et al. and Lonergan et al. Figure credits: Kate Lonergan (CC 4.0).
Most failures occur in the local distribution network; however, failures in high-voltage transmission systems can be particularly devastating as they can quickly cascade across the grid, disrupting essential services in large geographic areas. Even comparatively wealthy nations can struggle with the impacts of power outages. For example, a recent power outage in the Iberian Peninsula led to 9 deaths, €2-5 billion in economic damages, and brought public transport across the region to an hours-long standstill. Likewise, a 2021 winter storm in Texas was linked to over 50 energy-related deaths and left millions of people without consistent power for days. The longest outages were found to affect regions with high shares of vulnerable populations.
The Iberian and Texan power outages help illustrate that the gravity of power outages can be captured in some hindsight statistics, like energy-related deaths and total economic damages. Other metrics like total energy not served (MWh) and excess visits to emergency rooms are also available. However, these statistics do not capture the full range of adverse human experiences (Figure 1) caused by power outages and can often only be applied after a power outage occurs.
Measuring the human impacts of power outages before they occur
One well-known and popular method of measuring the human impact of power outages before they occur is the Value of Lost Load (VoLL). The VoLL is usually defined as the money that end-users would be willing to pay to avoid a power interruption and is expressed as a cost, such as in €/kWh or €/hour (Figure 2). Because the VoLL can be calculated before an outage occurs and represented in monetary units, the metric can be used to weigh the costs of an outage versus the benefit of upgrading local infrastructure. In addition, the VoLL can be derived for entire consumer segments (e.g., residential consumers in Italy or businesses in Switzerland), making it a useful metric in cross-border reliability studies.
Figure 2. Value of Lost Load (VoLL) for European domestic consumers as reported by the Cambridge Economic Policy Associates in a report for the Agency for the Cooperation of Energy Regulators (ACER). Figure created by K. Lonergan.
Though the VoLL is widely used, the metric also has several shortcomings. VoLL estimates are notoriously sensitive to how they are constructed and sensitive to locally varying factors like the ability to use alternative energy carriers (e.g., a wood-burning stove). Likewise, it is difficult to place a monetary value on some activities made impossible by a power interruption, such as staying warm or maintaining communication. Using single VoLL estimates alone also fails to consider the differentiated impacts that power loss can have on more vulnerable consumers.
One alternative for measuring the impact of power outages from a more human angle is to consider whose power is interrupted. Specifically, in our recent work, we apply a vulnerability index to analyse power outages and their relative human impact, and guide reliability planning. A vulnerability index can be constructed using already-collected demographic data, such as age & health data, the share of the population at-risk of poverty, and mean access time to essential services.
Moreover, considering community vulnerability is already standard practice in disaster risk reduction planning. As such, even though the factors contributing to an individual’s vulnerability vary according to the threat they face – i.e., characterising vulnerability to a power outage versus a forest fire or hurricane would require considering different individual and environmental factors – accounting for vulnerability within power systems planning could mitigate human harms during emergency settings.
Mitigating harms caused by power outages
Measuring the damage caused by power outages is a crucial step towards mitigating future harms: identifying the most vulnerable consumers and regions can help prioritise infrastructure upgrades and recovery actions. For example, we found in our recent work that upgrading a select group of poorly performing high-voltage substations would have a disproportionately high benefit for delivering more equal and reliable power service across Italy.
Moving forward, improving the scope and availability of past outage data would help system planners identify what investments & operational strategies could best support vulnerable electricity consumers. Historically, accessing good-quality data has been impeded by the lack of publicly available datasets, with much of the empirical knowledge being scattered across TSOs, utility companies, and regulatory bodies. Moreover, public datasets tend to be scope-specific and contain a small number of outages, usually only events of high public interest. Some efforts are underway to address this gap, including work done by ETH, the World Bank, and United States national laboratories, but more work is required to enable vulnerability-informed reliability planning on a global basis.
Individuals can also take steps to mitigate the impacts of a power outage. For example, individuals can prepare for a power outage by having flashlights, bottled water, a first-aid kit, a radio, and some hand sanitiser at home. Having uninterruptible power supplies, like batteries, could also help keep critical devices online.
At the same time, not all individuals are able to take steps to adequately prepare for a power outage. The factors impeding outage preparation often overlap with the factors that make someone more susceptible to the impacts of a power outage, such as financial barriers and mobility limitations. Here, communities ought to step in and ensure that these vulnerable individuals receive support. Support can include specific actions like ensuring adequate provisions are available, helping move vulnerable consumers to electricity-secured locations, and checking in on vulnerable people during a power outage. Extended families, neighbourhood associations, and even electricity providers can all play a role.
Altogether, both top-down and bottom-up actions are required to mitigate the harms of power outages: electricity providers can guide infrastructure planning to reduce the likelihood of harm, and individuals & communities can take steps to protect their well-being in case an outage does occur.
Luckily, the interconnected European Grid within the area of ENTSO-E is probably one of the most reliable electricity grids all over the world! This is my perception – as an energy expert, by the way, who taught “Power Systems” at a university of applied sciences up to last year.
Besides short and announced switch-offs, I only just remember one single unannounced regional blackout during my life-time (i.e 71 years): That was in my teenage years, when a 50-kilovolts cable was damaged due to road construction works, which resulted in a blackout of several hours – and sadly enough to a fatal accident in a substation of the energy supplier, while attempting to establish an alternative supply pathway.
So, I cannot see any need for mere consumers to become “preppers” with regard to electricity supply!