Critical Infrastructure Resilience in Sweden - Comparing Swedish critical infrastructures based on interruption data

Elsa Axelsdóttir and Rasmus Jonason Bjärenstam, both students at Lund University, studying in the Division of Risk Management and Social Safety won the Swedish Risk Management Association (SWERMA) award in 2019, sponsored by If P&C Insurance. Their essay, Critical Infrastructure Resilience, compared Swedish critical infrastructures based on interruption data.

Today’s modern societies are becoming increasingly dependent on the vital societal functions that technical critical infrastructures provide, for example the availability of services such as electricity, tap water and internet connectivity. Hence, it is of essence that these infrastructure systems are resilient to interruptions.

According to the authors, “Suppose a system, any system, provides a service which is of great importance. That service will probably be delivered at different performance levels if studied over a period of time. Most certainly there are times when the system is not performing as expected, which is something we want to avoid; but when this happens, we want to restore service delivery to the expected level as quickly and efficiently as possible.

The basic idea of the resilience approach is to define this level and measure it, over time with 100% being perfect and 0 %, where the service is not delivered at all.”

railroad tracks.
Rail transport in Sweden consists of over 15 000 km of track. Photo: Getty Images

Purpose of the study

The purpose of their thesis was to investigate and contrast the resilience levels of different types of technical critical infrastructure in Sweden. A generic resilience assessment approach was developed to utilise interruption data, based on data on duration and consequence of failures that are gathered by infrastructure owners. This interruption data is used as a measure to indicate the level of ‘functionality’ of each infrastructure over a given duration.

When the functionality is analysed over time, a so called ‘resilience curve’ can be derived. These resilience curves for different infrastructures are then used as basis to contrast and compare resilience levels achieved by the different infrastructures.

In their study, the authors note that, “The scope of the research was limited to Swedish technical critical infrastructures, of which we have analysed data from the electricity transmission system, several electricity distribution systems, the national road transportation system, the national railway transportation system, the largest water supply system in Sweden and telecommunication systems; where the telecommunication systems has been split up into three sub-infrastructures with respect to mobile communication, fixed telephony and broadband services.”

water power plant.
Reliable water supply is vital for any community. Photo: Getty Images

The resilience assessment approach has successfully been applied to interruption data, enabling objective quantifications in a unified manner, for eight different Swedish critical infrastructures.

The idea was to simplify a system’s ability to deliver its service to one unitless dimension, in the thesis this is called “functionality”, and to measure it over a period of time, as the basic idea amongst most of the “resilience concepts” that were studied. The authors explain that, “A more resilient system will be less affected and/or recover faster from a disruption. The tricky part is to figure out how to define and quantify the functionality of the system, we did so by studying interruptions of technical critical infrastructures, but there are certainly other ways of doing this.”

The study was carried out as a quantitative empirical data analysis. The data gathering process was a significant part of the conducted work, completed via emails, phone calls and online meetings.

The main scientific contribution we brought to this idea of resilience, is that we found a way to do it in a unified, generic manner, across different infrastructures so that comparisons can be made.

Results and conclusions

The results reveal that the Swedish electricity transmission system is the most resilient with extremely few interruptions that results in any consequences in terms of disrupted service. Meanwhile, the research found that the least resilient, is the railway transport system.

Second least resilient infrastructure is the electricity distribution system. The rest of the infrastructure systems e.g. water supply, road transport and telecommunication (with regard to mobile communication, broadband services and fixed telephony), lie between these three, all positioned on relatively similar levels.

Examples are provided for the possible fields of usage with respect to the suggested approach and the presented results. It is concluded that the results produced by the approach could be useful in risk management processes and related work within spatial planning or societal safety.

The possibility to measure resilience as a function of time in a unified manner across different types of infrastructures, enables comparisons between the infrastructures. Such information could be used as a basis for decision makers to e.g. evaluate policy and mitigation decisions.

The authors' statements

Further, the authors note that, “critical infrastructures should be either legally obliged or encouraged by official instances to gather interruption data. If possible, one single centralised authority could be in charge of deciding what specific data required of each individual Technical Critical Infrastructure (tCI), given with unified parameters and thresholds.”

The authors state that, “In our thesis we conclude, the most critical infrastructures probably could adapt such a view of functionality with available and measured data, and probably also benefit from doing so.

For businesses, we believe there are probably many companies out there with data available on monitored systems, that could adapt this view of resilience by analysing their interruptions. When done in a unified manner, it can always be compared and contrasted between different systems - as the functionality is unitless.” 

For more information, please visit the Lund University ‘Student Papers’ page to see the full publication.

Article by: Kristian Orispää

Contributors: Elsa Axelsdóttir and Rasmus Jonason Bjärenstam