Engineers responsible for keeping Britain’s lights on have warned they no longer have control of the electricity system as renewable generation, batteries and local power sources expand faster than operators’ ability to monitor them.
The warning appears in a confidential 82-page report commissioned by the National Energy System Operator and revealed by the Mail on Sunday. It raises serious questions over whether NESO has the visibility, forecasting tools and operational systems needed to balance supply and demand safely.
A group of NESO engineers said:
We the engineers have asked Ofgem to investigate and ensure the system is safe for two years now. That is simply done by asking for proof that NESO can always work out how much energy is required. And they won’t do that and they won’t investigate. So we have told the world.
“June 23 was simply another day. We don’t have control of the system. We have tried our best. It’s now over to the public and the regulator. Please help”
Britain is moving from an electricity system built around a relatively small number of large, predictable power stations, to one involving thousands of wind farms, solar panels, batteries and smaller generators connected across local networks.
Much of that generation does not appear clearly in NESO’s real-time view of the system. Control room teams must instead rely on forecasts and estimates when deciding how much electricity to procure and which assets to instruct.
The report reportedly warned that NESO lacks a single centralised model for calculating the amount of power required to keep the grid stable. Forecasting methods can vary and key decisions may depend too heavily on the judgement of individual operators.
Those concerns came into sharp focus during the extreme heat on 23 June when demand increased while wind generation, gas plants and electricity imports were under pressure.
Grid frequency repeatedly moved outside NESO’s normal operating range and remained there for around 48 minutes in total. Five transmission constraints were also breached, with the largest exceeding its limit by around 700MW.
Internal reports produced after the event stated that system constraints had been breached and system security was compromised. NESO said those were preliminary assessments and insists the system remained secure, no customers were disconnected and frequency stayed within statutory limits.
Operators bought around 1,500MW through international interconnectors between 5pm and 6pm but reportedly received just 262MW. They also called on around 700MW of battery power, halted 800MW of exports to the Netherlands and requested 500MW of emergency assistance from France.
Whistleblowers have separately alleged that senior staff attempted to downplay the seriousness of the incident and discouraged control room operators from creating a complete record of decisions. Those allegations remain unproven and are being investigated independently.
Ofgem has also ordered an in-depth review of the June event, covering system conditions, operational decisions and compliance with security standards.
The issue now goes far beyond one difficult evening. NESO’s own engineers are claiming they cannot reliably calculate how much electricity is needed or maintain full control of the system they are responsible for operating.
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