18 August 2026
Summer used to be the quiet part of the energy calendar. With lower energy demand and familiar consumption patterns, it was a time to plan and review projects ahead of winter which typically requires greater management and preparation against unpredictability.
Energy resilience was traditionally associated with colder calendar months. But, with summer periods seeing more extreme and frequent hot weather, that picture is changing.
In June this year, hot weather put extra pressure on Great Britain’s electricity system, prompting the National Energy System Operator (NESO) to issue an Electricity Margin Notice. These notices are more commonly associated with winter, when demand is usually highest. June also saw England record a new minimum temperature record for the month at just over 23 degrees. This is significant as the Met Office categorises any day where the average daily temperature is above 22 degrees as an ‘active cooling day’ – used to indicate increased energy demand from cooling.
Prices have also remained hard to predict due to further market volatility this year. DESNZ's Quarterly Energy Prices data shows gas and electricity prices moving throughout the year, meaning understanding how this impacts your energy portfolio is more important than ever.
Greater cooling, ventilation and refrigeration needs mean increased electricity use. In some sectors this is affecting summer demand peaks, changing traditional energy profiles. Energy managers are starting to treat these summer profiles and resilience preparation with as much of a detailed eye as they do winter ones.
How changing summer energy demand affects businesses
Heatwaves can significantly alter a site's normal fuel mix, reducing gas consumption while increasing electricity demand. However, for some large industrial users to continue to operate, they may see gas demand remain stable or increase, regardless of external temperatures. This is often the case when it is used for manufacturing processes, such as steam generation, food production, chemicals or glass production.
Electricity demand can move in the opposite direction. As temperatures rise, cooling, ventilation and refrigeration systems often work harder and for longer periods, increasing electricity consumption across offices, retail sites, warehouses and industrial facilities.
The secondary impacts of extreme heat can be just as disruptive as the heat itself. Extreme heat can affect product quality, equipment performance, site safety and customer service. Even a short period of disruption can create wider operational and financial consequences. Increased temperatures can also expose weak points in business continuity plans, particularly where energy use, maintenance, staffing and supply chain resilience have not been stress-tested together.
As consumption patterns change, organisations become more exposed to cost volatility and operational disruption during periods of extreme heat.
How to assess your organisation's summer energy exposure
Resilience does not have to mean investing in generators or battery storage, although for some organisations that is part of the picture. For many, it starts with a clearer view of changing consumption patterns.
From there, the task is to identify where your peak loads occur, how much flexibility you have to shift or reduce use if prices spike, and whether your current contract gives you room to absorb short-term price movement or leaves you exposed.
A multi-site retailer, for example, might find that a handful of stores drive most of the summer peak. Those are the sites worth reviewing first, whether that's assessing cooling efficiency, identifying opportunities to reduce peak demand or understanding where energy costs are most exposed during periods of extreme heat.
Understanding where, when and why energy usage changes within your business is essential. A site that has consistently high usage is fine if expected and managed effectively. However, a site that’s profile shifts dramatically in hot weather could face challenges.
Historical consumption data remains important, but organisations should also consider how more frequent periods of extreme heat could influence future demand patterns when forecasting summer energy requirements.
Common energy resilience gaps
Interestingly, recent research conducted by SEFE Energy found that reliability was cited more frequently than price when UK organisations were selecting energy contracts. Among industrial businesses, 64% identified reliability as a key consideration. This reflects a broader shift in how organisations think about energy.
However, organisations are commonly caught out by three areas when it comes to summer resilience planning.
Firstly, relying on historic consumption patterns only or assuming summer usage will remain stable. This data may not be reflective of current consumption or accurately reflect future needs, making demand forecasting more challenging.
Aligned with this is planning resilience around winter only. We know summer energy needs are changing, so focusing on colder months will no doubt put organisations on the backfoot and potentially miss emerging operational risks. Scheduling time bi-annually, at a minimum, will ensure reviews of usage can be assessed in detail and consider any recent challenges or changes that need to be accounted for.
Finally, limited visibility of site-level demand can also be a common gap businesses face. Knowing which locations create peak exposure, and how consumption changes as a site level in hot weather, helps prioritise interventions and inform future decisions.
Without a clear understanding of how energy use changes during hot weather, businesses may be less prepared to respond to increased demand and associated cost pressures.
How to build resilience for the future
Organisations that look at their summer demand before the season starts have more room to manage it. That could mean reviewing contract flexibility, identifying opportunities to shift non-essential energy usage away from peak periods, or simply having better evidence for budget conversations.
For a retailer, that might mean checking exposure store by store. For an office-based organisation, it might mean looking at how cooling and IT loads overlap on the hottest days. For larger industrial organisations it may mean identifying which sites, processes or production lines are most exposed to summer demand peaks and where operational flexibility exists to reduce pressure during high-demand periods.
Whatever the priority, the earlier this happens, the more choices stay on the table once the heat arrives.
An energy audit is a practical first step. It gives you a clear baseline for every planning conversation that follows. SEFE Energy specialists can help organisations review usage data, explore flexible contract options and keep track of market changes before they affect future costs. For those planning further ahead, our decarbonisation solutions can help build that resilience alongside day-to-day energy management.
Summer planning gives energy teams more time, more options and a clearer view of what could affect costs later in the year.