Projected Solar and Wind Surplus in the UK by 2030: A Preliminary Analysis
Analysis of historical generation data and projected renewable capacity suggests the UK electricity system could experience significant periods of excess power from solar and wind sources by 2030, necessitating substantial increases in energy storage capacity. This assessment is based on modeling future output using half-hourly generation data from August and September of the current year, sourced from the NESO generation database.
The modeling assumes the UK meets its current government targets for renewable energy installation. Solar capacity is projected to be 2.41 times the level anticipated in late summer 2025, with a constant capacity factor (the ratio of actual output to potential output). Wind capacity is projected to increase, incorporating the UK government’s anticipated improvements in capacity factors: onshore wind from 25% to 36%, and offshore wind from 38% to 49%. Importantly, these increased capacity factors are applied to new installations, with existing wind farms continuing to operate at their current levels.
Applying these projected capacities to the meteorological conditions observed in August and September of the current year, while conservatively assuming minimal contribution from other sources (with the exception of maintaining current nuclear output levels), reveals a fluctuating supply picture. The analysis indicates periods were wind and solar, combined with existing nuclear generation, could fully meet national electricity demand.
Specifically, the modeling shows a potential surplus peaking at approximately 2.5 TWh in early August, followed by a period of deficit. However,a sustained period of excess generation begins around mid-August,escalating to a surplus of around 7.9 TWh by August 22nd – a dramatic shift from the earlier deficit of 0.25 TWh. This suggests the potential for prolonged periods where solar and wind generation significantly exceeds demand.
It’s important to acknowledge the limitations of this analysis. Electricity demand is assumed to remain static, a factor that may change as electrification increases through the adoption of heat pumps and electric vehicles. Moreover, the projected increases in wind turbine efficiency may not fully materialize.
Crucially, the modeling deliberately assumes minimal contribution from other generation sources – gas, imports, biomass, etc.- to provide a conservative, lower-bound estimate of potential surplus.Even under this highly restrictive scenario, the results demonstrate that substantial periods of excess electricity generation from solar and wind are likely by 2030, highlighting the urgent need for significantly expanded energy storage solutions beyond current plans.
