Energy explained blog: Electricity Margin Notice 24.06.26

Yesterday, NESO issued an Electricity Margin Notice (EMN) to the electricity market. Electricity supplies remained secure throughout and the EMN has now been withdrawn.

Let’s walk through what an EMN is, and what happened. 

Why was an EMN issued?

In recent days, Great Britain and parts of Europe have experienced unusually high temperatures. At the same time, wind and gas generation availability was lower than expected.

Together, those factors resulted in tighter electricity margins than we would normally expect for this time of year. As part of our planning for those conditions, NESO issued an EMN for Wednesday evening's peak demand period. 

An EMN is one of the operational tools available to our control room. It is used to notify the market that additional generation capacity may be required and to encourage market participants to make any available capacity known. It does not mean electricity supplies are at risk and it is not a warning of power cuts.

What actions did NESO take?

Operating a reliable, resilient electricity system means responding to changing conditions in real time.

Alongside the EMN, our control room used a range of operational tools and market actions to maintain the balance between supply and demand, including our demand flexibility service. We contacted generators to understand their individual risks and to see if any generation outages could be rescheduled. 

We also worked with neighbouring European transmission system operators, making use of existing arrangements that allow coordinated action during exceptional system conditions, like the temperatures we are seeing this week. 

The market responded to the EMN and additional capacity became available including through demand side response. Throughout the period, electricity supplies remained secure and the system continued to operate reliably. The EMN was withdrawn on Wednesday afternoon once margins improved.

What does this tell us?

In our Summer Outlook, we said we expected to have sufficient electricity available to meet demand this summer and that we may need to use a range of operational tools to manage changing system conditions. This was one of those occasions.

Modern electricity systems are complex and weather, including extremes like this week, influences how they operate. Our role is to anticipate changing conditions, use the tools available to us and maintain a secure and reliable supply of electricity for homes and businesses across Great Britain.

Yesterday's EMN was one example of that in action. We look forward to discussing this with our customers and stakeholders at our next Operational Transparency Forum.