GB power imports fell 12% last year as wind generation reached a record high, according to Montel EnAppSys.
Average net imports through interconnectors were 3.33GW in 2025, around 0.5GW lower than in 2024, the analysis experts said.
On an hourly basis, flows remained predominantly in a net import position, although periods of strong renewable output occasionally flipped GB into net exports.
France and Norway provided the most electricity to GB on average at around 2.5GW and 1.0GW respectively.
Average hourly wind generation reached a record 9.82GW, nearly three times higher than a decade ago.
Wind provided 67.6% of aggregate renewable output, which rose to 14.52GW overall compared to 13.49GW in 2024.
Renewables accounted for 47.5% of Britain’s power mix in 2025, with gas at 28.9%, imports at 10.9% and nuclear at 12.7%.
Dr Jake Thompson, GB market expert at Montel EnAppSys, said: “The rise in wind generation tracks the dominance of renewables in Britain’s power mix as the country seeks to produce more of its electricity from cleaner sources.
“The rise in renewable generation comes as nuclear generation continues to decline, while coal is out of the picture entirely following the decommissioning of Ratcliffe-on-Soar in September 2024.”
Nuclear generation fell 11% to 3.9GW due to unplanned outages and maintenance at several reactors, including Hartlepool 1 and 2 and Heysham units.
Constraints during high-wind periods meant significant volumes of potential wind output were curtailed, highlighting a need for grid reinforcement, Thompson added.
Negative price events also increased with 149 hours recorded in the EPEX auction and 177 hours in NordPool.
Peak prices in the NordPool market almost doubled from around £496/MWh in 2024 to £979/MWh in 2025.
Thompson stated: “As we produce more of our electricity from renewable sources, this will increase the likelihood of negative price events this year and beyond.”