The UK National Energy System Operator on Friday issued another power supply warning as soaring temperatures across Europe put the region’s networks to the test. It’s unusual for the National Energy System Operator to issue a market alert in summer.
Such warnings are typically associated with winter ‘dunkelflaute’ periods, when cold weather coincides with weak wind generation. The alert underscores the new extremes the grid must adapt to: in this case, a surge in cooling demand coinciding with low wind generation and reduced nuclear output.
The National Energy System Operator (NESO) has urged generators and suppliers to make additional capacity available to bolster reserves amid an estimated margin shortfall of 671 megawatts between 7pm and 10pm local time, according to a notice.
A similar warning was issued for Wednesday, with the network operator citing extremely high temperatures across Great Britain and continental Europe as the main driver of the tight supply outlook. Evenings are proving to be a particular crunch point as solar comes offline.
This means NESO needs to pay generators, mainly gas plants, to step in to meet demand. The UK grid operator issued a second power supply warning for Friday evening. Image by doughnuts67 via iStock.
While the heat wave has been less severe in the UK than on the continent, the power market is closely linked to neighboring countries through interconnectors beneath the North Sea.
The hot weather has boosted cooling demand across the continent while forcing output cuts at several French nuclear reactors because river water used for cooling has become too warm. Demand is forecast to peak at just below 36 gigawatts on Friday evening, according to Elexon, slightly easing from Thursday’s peak.
Bloomberg has forecast that weak wind generation is crimping supply with average output of about five gigawatts during the day, well below the roughly nine gigawatt average so far this year. In neighbouring France, the situation is also tight.
As much as 18 gigawatts of nuclear capacity is at risk of curtailment, straining regional supplies and limiting electricity exports to Britain.
UK intraday power for Friday evening is trading above £200 a megawatt hour, above the price set in Thursday’s auction, suggesting the market is tighter than traders had anticipated.
NESO wants to maintain a 700-megawatt operating reserve at all times to ensure that the grid doesn’t go down. For Friday, however, about 1.1 gigawatts of generation cannot be counted toward that buffer because of transmission constraints, reducing the available safety margin.
At times of stress on the system, the system operator can pay generators to ramp up output through the balancing market. LCP Delta data show gasfired generators earned about £10 million in Balancing Mechanism revenue between June 22 and June 25.
The call for more supply, known as an Electricity Margin Notice, is a routine tool used to encourage generators, interconnectors and demand-side providers to make additional capacity available.
It does not mean blackouts are expected. Such notices are more commonly issued during winter, when UK electricity demand is typically highest.
