On Monday, Britain's grid felt unexpected strain on an otherwise ordinary day. There were no big outages or extreme weather, and Scotland's turbines were delivering strong output.
The chokepoint was the network. Not enough power could move south to London and the southeast, so the National Energy System Operator took emergency steps to secure extra electricity from France. In southeast England, transmission assets that were due to be restored to operation were still offline, further constraining transfers into the southeast. While NESO was seeking extra supply from France, southern England was still exporting electricity via other interconnectors to Belgium, the Netherlands and France.
The episode highlighted a familiar weakness: the UK can have enough generation overall yet fail to deliver it to where demand clusters. Wind projects have been built far from major load centers, and they are arriving faster than the transmission to carry their output south.
That mismatch is getting pricey. LCP Delta's data shows September's balancing costs hit a record just over half a billion pounds. It also found actions on a single Tuesday in October cost £38.4 million, a one day high, equal to $51.2 million, with October figures through Oct. 11. NESO's figures indicate the UK may spend over £3 billion on grid balancing this year.
Those bills reflect what NESO spends to keep supply and demand aligned, especially managing constraints. It pays some Scottish wind farms to switch off when the network is congested, then pays much more for gas plants nearer cities to switch on. According to Jason Mann, a senior managing director at FTI Consulting, "These wind farms were built with very limited consideration of where that electricity would be consumed." "Those costs are locked in for generations." As LCP Delta's Shivam Malhotra put it, "This is something we'll keep seeing."
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Many current pinch points trace back to the 2010 connect and manage approach under then Energy Secretary Ed Miliband, which let renewable projects plug in ahead of completing the grid upgrades needed to carry their output. Successive governments of both parties then subsidized rapid wind expansion without a comparable buildout of transmission.
The risk was flagged early. In 2008, John Mogg, then Ofgem chair, warned Miliband that connecting more Scottish renewables ahead of added capacity could cause constraint costs to "increase significantly." Those costs were about £300 million at the time, and based on NESO data and the operator's forecasts, this year's total could be roughly ten times that.
System resilience is also under review. Ofgem has opened a probe into NESO's conduct during an incident in a June heat spell when tight margins strained the grid. No customers lost power, and the regulator is assessing whether relevant security standards were met.
Last year, during his second term as Energy Secretary, Miliband turned down a shift to a zonal electricity market that would have established different prices across Britain to mirror the grid's physical constraints. Higher prices in the south could have signaled local gas plants to start and encouraged flows into Britain through interconnectors, reducing the need for NESO to correct imbalances after the market cleared.
Consumers ultimately pay. When it's windy and sunny, wholesale prices can drop, but network bottlenecks can eat into those gains if NESO has to pay to start up gas plants in other locations. Energy Secretary Miatta Fahnbulleh called the current setup "candidly not fit for purpose," while saying she is "100% confident the lights won't go out this winter."
"The long-term choice for the UK is between investing once in modern grid infrastructure or continuing to pay for imported fossil fuels year after year," said Benj Sykes, UK chair of Orsted A/S. He urged faster grid upgrades, storage and other flexibility to improve security and "tackle the energy affordability challenge."
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