Power surges in hot weather: Understanding the strain on grid infrastructure
As temperatures rise, so do power surges. Discover how heatwaves strain electrical grids and how to protect infrastructure and critical systems.
2026 saw June temperatures break records across Europe, with peaks of 36.4oC in the UK (in Somerset), much of Europe experiencing temperatures above 30oC, and countries like France and Italy seeing the thermometer reach 40oC in many areas. Such extraordinary heat even prompted the UK National Energy System Operator (NESO) to issue a rare Electricity Margin Notice (EMN) to the electricity market, due to tighter electricity margins than those normally expected for this time of year.
It seems counterintuitive, but too much heat is a problem for solar panels too. Their efficiency drops incrementally once temperatures rise above 25oC - at the exact same time that there is increased demand on the grid from households and businesses turning up their air conditioners or fans (unsurprisingly, a few retailers have reported record sales of portable units too).
As global temperatures continue to rise, these heatwaves are placing unprecedented pressure on electrical grids worldwide. For industries reliant on consistent, high-quality power supply, understanding how hot weather contributes to power surges - and the implications for infrastructure - is becoming increasingly critical.
Why hot weather triggers power surges
During periods of extreme heat, electricity demand rises sharply. Air conditioning systems, ventilation units, refrigeration equipment, and cooling systems in buildings with sensitive equipment like data centres, all operate at higher intensities and for longer durations. This surge in demand can create instability in the electrical network.
Key contributing factors include:
- Peak demand spikes: Afternoon and early evening periods during heatwaves often see record-breaking loads.
- Thermal stress on conductors: Higher ambient temperatures increase resistance in cables, reducing their efficiency and capacity.
- Grid balancing challenges: Maintaining voltage and frequency becomes more complex when demand fluctuates rapidly.
When the grid struggles to balance supply and demand, voltage fluctuations and transient events can occur. Transients are quick, unexpected spikes in voltage or current (positive or negative) that can significantly impact system performance and component lifespan. They are commonly experienced as power surges, when the voltage exceeds the regular flow of an electrical system.
The impact on grid infrastructure
Heat-related surges don’t just affect end-users; they also accelerate wear and degradation across electrical infrastructure. Areas of stress include:
- Cable performance degradation
Cables operating close to or beyond their designed thermal limits can experience insulation breakdown over time. Elevated temperatures reduce current-carrying capacity (ampacity), meaning systems may become overloaded even within nominal design parameters. - Transformer stress and failure risk
Transformers are particularly vulnerable during heatwaves. Increased load combined with higher ambient temperatures reduces cooling efficiency, potentially leading to overheating, reduced lifespan, and in extreme cases, catastrophic failure. - Ageing infrastructure vulnerability
Older grid systems, not designed for today’s demand peaks or sustained high temperatures, are especially susceptible. Thermal cycling — repeated heating and cooling — can weaken materials, connections, and joints, increasing the likelihood of faults.
Consequences for industry and critical operations
For commercial and industrial users, power surges during hot weather are not just an inconvenience — they can result in:
- Damage to sensitive equipment such as control systems, servers, and automation technology
- Operational downtime, particularly in manufacturing or processing environments
- Safety risks, especially where surge events affect critical systems
In sectors like energy, utilities, railways, and construction, maintaining system integrity during peak demand periods is essential. Addressing the risks associated with heat-induced power surges requires both infrastructure resilience and careful system design.
The importance of cable selection
Specifying cables – whether for grid networks or other purposes - with higher temperature ratings, robust insulation materials, and proven performance under thermal stress is essential. Depending on their use, for example, cables might have XLPE insulation (such as cables over 1kV and under 45kV) or EPR (more common in the United States for MV cables). You can read more about insulation in our Expert’s Guide to Medium Voltage Cables.
Smart grid technologies and real-time monitoring help operators identify stress points, balance loads effectively, and reduce the likelihood of surge events, while replacing ageing assets with modern, heat-resilient components and implementing proactive maintenance strategies can significantly reduce risk.
Other preventative measures include installing surge protection devices (SPDs) at critical points helps safeguard equipment from transient voltage spikes.
Our cables are extensively tested in The Cable Lab, so our customers can be assured that the cables we provide are going to withstand imbalance within the parameters of the cable's specified performance.
Insulation integrity and quality are fundamental to the reliable operation of MV and HV cable systems. Under high electric field stress, even minor defects within the insulation can lead to localized field enhancement, initiating partial discharge (PD) activity. Over time, this progressive PD degrades the dielectric, potentially leading to failure. To mitigate this risk, our cables are routinely tested for partial discharge at both power frequency and very low frequency (VLF). These diagnostic tests allow early detection of insulation defects and ensure the long-term performance of the cable system.
Looking ahead
As climate patterns evolve and energy demand increases, grid resilience in extreme weather conditions is becoming a defining challenge for energy systems globally. For cable manufacturers, specifiers, and infrastructure planners, this presents both a challenge and an opportunity — to innovate, improve standards, and deliver solutions capable of withstanding the thermal and electrical stresses of a changing environment.
At Eland Cables, understanding the interaction between environmental conditions and electrical performance is central to delivering reliable cable solutions. By focusing on quality, compliance, and technical support, businesses can better equip their systems to handle the demands of modern energy use — even under the most extreme conditions.
Speak to our Sales team today to discuss your cable needs.
