Construction managers are being advised to review on-site power strategies to maintain resilience during periods of extreme heat, as weather volatility could affect project delivery.

The reminder from Aggreko comes after the National Energy System Operator (NESO) issued an electricity margin notice that power supply could be squeezed after temperatures soared across the UK.

While the notice was later withdrawn after emergency supplies were secured from the EU,[1] the engineered energy and temperature solutions specialist says that similar conditions will place further strain on the grid and may lead to further alerts if high demand persists.

Rising temperatures form part of a broader challenge highlighted in Building in Resilience, an Aggreko report which found that over 70% of UK construction professionals have experienced major delays due to changing weather conditions.

Extreme heat is now considered the most significant weather-related risk among UK respondents.

Against this backdrop, Aggreko is encouraging the construction sector to consider more flexible approaches to site power. Integrating technologies such as battery energy storage systems (BESS) alongside traditional generation can help improve resilience, optimise energy usage and reduce reliance on diesel-only backup.

Tom Adlington, sector sales manager for building services and construction at Aggreko, said: “We’ve seen how soaring fuel prices have impacted the operational budgets of construction sites in recent months. This level of heat adds another layer of complexity by increasing the potential for reliance on back-up power strategies, which are often diesel-led.

“Integrating BESS into the on-site energy mix can reduce dependence on diesel, gain greater control over energy spend and avoid downtime due to high temperatures. Using them alongside Stage V generators running on hydrotreated vegetable oil also offers a route to energy-efficient emission reduction, helping the sector in its decarbonisation efforts in the process.”

BESS store electricity when on-site energy usage is low and discharge it during peak times, reducing generator run hours and improving system efficiency. They also provide supplementary power far faster than gas or diesel generators, acting as a stopgap between the grid and other backup systems.

Discover more about battery energy storage systems here.

[1] https://www.telegraph.co.uk/business/2026/06/24/grid-operator-demands-more-power/