The UK’s power supply could have “some tight days” in December and January, despite energy prices more than doubling, one of the country’s energy operators said on Friday.
At the same time, a last-minute deal with a Belgian interconnector firm would provide for an additional five per cent of forecast demand, maintaining gas import capacity and allowing more flexibility for the grid at times of demand strain.
Supply agreements should mean there is enough gas and electricity to meet peak demand through winter, according to forecasts published by National Gas and National Energy System Operator (Neso).
Front-month gas and power prices have risen about 180 per cent and 120 per cent since the outbreak of the US-Iran war in February of this year, and this is set to have a rising impact on consumer bills.
Neso predicts a “small number of low surplus days”, which balances supply and demand across the grid in real time. This would require routine balancing tools such as electricity margin notices, and did not indicate a risk to electricity supplies, Neso said.
Peak gas demand is expected to reach 493 million cubic metres per day this winter, 2 per cent higher than last year, according to a separate report by National Gas, also published on Friday. This is largely due to stronger demand from power stations. Overall gas demand is expected to fall by 1 per cent as a result of consumer switching.
Peak gas supply capacity is estimated at 592 mcm/day, leaving a buffer of 99 mcm/day but a “highly unlikely” stress scenario, such as the failure of the largest single part of the transmission system, would shrink the buffer to 18 mcm/day.
National Gas said its forecasts were improved by a deal it reached on Thursday with a Belgian Interconnector pipeline to boost gas import capacity. Gas imports to the UK through interconnectors with Europe declined in recent years because of their maintenance costs, including the capacity of the two-way Belgium- Britain Interconnector.
Yet lower levels of gas storage in Europe – also as a result of the war – would probably restrain imports. The British energy regulator Ofgem said it would launch a consultation on how to recover the costs of this capability, as it approved the agreement on Thursday.
Disruptions in the global liquefied natural gas (LNG) market could also still affect supplies.
“Our analysis shows that Great Britain is expected to have sufficient gas supply capability to meet demand throughout winter 2026/27, even under a range of very unlikely high-stress scenarios,” said Glenn Bryn-Jacobsen, National Gas's director of energy systems and resilience.
The UK's gas storage levels were estimated to be the lowest in Europe – at 48 per cent of its capacity – according to analysis by the European network of transmission systems for gas (Entsog) earlier this month.
On the power side, there will be spare capacity of 5.9 gigawatts above peak demand – the equivalent of 9.5 per cent of peak demand – during a typical cold spell, according to Neso. That margin is similar to recent winters, and is wider than during the 2022 energy crisis.
Higher peak demand has largely been offset by additional battery storage, gas-fired generation and wind power, Neso said. The margin is also higher than its June estimate because it now expects more wind generation to be available during peak periods.
Neso said some days in December and January could be tight and require routine balancing tools such as electricity margin notices. It stressed that such notices signal a need for additional generation and do not indicate a risk to electricity supplies.
