Great Britain’s operators forecast enough winter energy capacity as the National Energy System Operator (NESO) flags tight electricity days and the Office of Gas and Electricity Markets (Ofgem) weighs a charge for gas import capacity.
NESO’s Winter Outlook covers Oct. 31, 2026, through March 31, 2027. It puts the de-rated electricity margin at 5.9 gigawatts (GW) above average cold-spell peak demand, or 9.5% of that benchmark, after reserve requirements are met. Separately, NESO modeled 30,000 scenarios for each winter day to forecast daily operational surplus. The margin is higher than NESO’s June estimate partly because of a methodology change, but the operator says that change leaves its overall outlook intact.
NESO identifies December and January, outside the Christmas period, as the likeliest times for tighter reserves. It may issue routine notices seeking additional reserves on those days; NESO says such notices do not mean supply will fall short.
National Gas forecasts overall gas demand will decline about 1%, while peak demand from power generation rises 7% as gas plants support the system when renewable output is low. Its projections also show UK Continental Shelf production falling about 5% and liquefied natural gas (LNG) imports rising about 6%. The peak-demand benchmark is 493 million cubic meters per day on a one-in-20 winter day, about 2% above last winter; supply capability is estimated at 592 million cubic meters per day.
Reuters reported that U.K. front-month gas and power prices had risen about 180% and 120%, respectively, since the Iran war began in February.
Interconnector Limited’s updated notice sets Belgium-to-Great Britain import capacity at 27.8 GW from October 2026 through March 31, 2027, versus 16.5 GW previously planned. The added 11.3 GW will be offered on interruptible terms. Interconnector had linked its earlier plan to reduce capacity to weak bookings and higher fixed operating costs. The revised agreement follows Ofgem’s earlier effort to maintain capacity on the Belgian gas link.
Ofgem approved the arrangement and is consulting on how National Gas could recover its costs. It estimates a charge of about £1.19 per gas customer annually for five years; customers who do not use gas would not pay. Ofgem says the retained route leaves an option to import gas when supplies are available, but the agreement does not purchase fuel or ensure deliveries. The consultation closes Nov. 20, 2026, with a final decision pending.
