British grid operator cancels plea for more power as temperatures soar

The body which oversees Britain's energy network has walked back a call for more power generation.

The National Energy System Operator (NESO) had last night issued a so-called electricity margin notice (EMN) for Wednesday evening as red heat health alerts came into force across large parts of England and Wales.

The public body later confirmed it was the first time it had exercised such a plea in the summer months.

But by Wednesday afternoon, NESO had cancelled the call. They did not give a reason why.

An EMN is essentially an operational alert to call for more power to be made available as the buffer between supply and expected demand comes under pressure.

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Before cancelling the call, a NESO spokesperson said: "Our forecasts are showing tight ​margins on ⁠the electricity system ⁠for tomorrow evening [Wednesday].

"This ‌is due to the impact ‌of extremely high temperatures affecting Great Britain and the continent and ⁠low wind."

But the spokesperson added it "does not mean electricity supply is at risk".

There is high demand for power during spells of very hot weather as fans and air conditioning units are switched on across the country in a bid to keep cool.

Calls for people not to travel on public transport and work from home in the areas covered by the red heat alerts only add to the drain.

In addition to the UK's wind generation capabilities being harmed by the high-pressure "heat dome" weather system, power transfers from the continent via interconnectors are also being squeezed due to the widespread high temperatures, strong demand and disruptions to supplies in northern France.

France is still expecting highs above 40C after a new record of 44.3C was provisionally set earlier in the week.

National Grid data showed natural gas accounting for a majority of UK power production on Wednesday morning.

Wind generation stood at just 12.6% of the mix, while solar made up 6.3% of supply.

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The cost of electricity is also up, mainly due to gas playing a leading role at a time when prices are higher than summer norms due to the effects of the US-Iran war on the global energy market.

The price per megawatt hour surged beyond £550 on Tuesday evening as football fans gathered to watch England's latest World Cup match.

Data showed the cost averaging £182 for the day as a whole - still way above a typical summer day and the yearly average £81.

The issue of an EMN is more common in winter time, again during periods of high pressure but which tend to bring colder conditions along with light winds.

Earlier on Tuesday, NESO said electricity supplies across Britain would "remain secure" in its early report covering the coming winter, despite the challenges posed by the Iran war.

Gas supplies, in particular, have been harmed by the effective closure of the Strait of Hormuz waterway since early March.

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