In recent years, temperatures exceeding 35°C have ceased to be an exceptional phenomenon in Poland. Experts at SPIE Energy Poland point out that such conditions are also becoming a major test for energy infrastructure operators, who must ensure stable electricity supplies in circumstances far removed from those for which much of the network was designed decades ago.
High temperatures affect the entire power system. The grid has to operate more intensively precisely when its operating conditions become less favourable. During the hottest hours of the day, electricity demand rises significantly, partly because of increased use of air conditioning and other cooling systems. At the same time, infrastructure is exposed to additional stress while facing technical limitations related to the physical properties of power equipment and networks.
In the case of high-voltage lines, elevated temperatures can reduce transmission capacity. This means that during periods of peak electricity consumption, operators have a smaller safety margin than they do in moderate weather conditions.
The main challenge, however, is not a single hot day. Much greater importance is attached to several consecutive days of high temperatures, when all elements of the energy infrastructure operate under increased load for a prolonged period while their cooling capacity remains limited. During such periods, power-line conductors heat up, expand and sag further. Meanwhile, equipment in substations faces more difficult conditions for dissipating the heat generated naturally during electricity transmission.
“Today, the energy sector operates in conditions that only a few decades ago would have been considered occasional. We are increasingly seeing situations in which high temperatures persist for many days. This requires operators not only to manage the grid on an ongoing basis, but also to consistently modernise infrastructure and increase its resilience to extreme weather events,” says Rafał Okoński, Commercial Director at SPIE Energy Poland.
A grid designed for a different climate
A significant part of Poland’s energy infrastructure was built at a time when heatwaves were less frequent and shorter. Networks were, of course, designed with appropriate safety margins, but climatic conditions that are now becoming more common were not the main reference point for designers.
As a result, Poland’s energy sector now faces the challenge of adapting existing infrastructure to a new reality. This applies to transmission and distribution networks, substations, control systems and solutions supporting the monitoring of equipment performance.
“Many overhead power lines currently in operation were designed on the assumption that the permissible operating temperature of conductors would be around 40–60°C. Modern solutions are already being adapted to operate at conductor temperatures of around 80°C, while the modernisation of existing infrastructure includes the gradual replacement of the most heavily loaded network components,” Okoński explains.
High ambient temperatures limit the ability to dissipate heat, while increased electricity demand raises the load on power equipment. Transformers are particularly sensitive, as they generate significant amounts of heat during operation and rely on cooling systems based, among other things, on transformer oil. During prolonged heatwaves, heat-exchange efficiency declines, increasing the risk of overheating and making continuous monitoring of operating parameters more important.
“Contrary to common perceptions, the most likely consequence of heatwaves is not a nationwide failure of the power system. More often, the risk concerns local overloads, failures of individual infrastructure components or temporary disruptions to electricity supplies. When the system is under particularly heavy load, mechanisms limiting electricity consumption by the largest industrial users may also be introduced, which could result in production stoppages and measurable losses for businesses,” the SPIE Energy Poland expert adds.
The risk increases further when periods of extreme heat are followed by severe storms and strong winds. This is why investments in digitalisation, automation and ongoing infrastructure diagnostics are becoming increasingly important for energy companies. Such solutions allow operators to identify potential problems faster and manage the network more effectively during periods of increased load.
Grid resilience becomes a key challenge for the energy sector
The growing frequency of extreme weather events means that infrastructure resilience is becoming one of the energy sector’s most important development priorities. This includes both upgrading existing network components and implementing new technical solutions that make it possible to better anticipate risks and respond more quickly to emerging problems.
“The greatest challenge for the energy sector is not a single day with temperatures above 35°C, but several such days in a row. In these conditions, infrastructure operates under elevated load for a prolonged period and the safety margin gradually decreases. This is why investments that increase grid resilience and measures enabling earlier identification of potential risk factors are so important,” Okoński stresses.
Both short- and long-term weather forecasts indicate that Poland’s energy sector will increasingly operate in climatic conditions that were considered exceptional only a short time ago. This means further infrastructure modernisation will be necessary, along with the development of systems capable of responding quickly to potential disruptions during increasingly demanding summer periods.
