In 2025, the UK achieved a significant clean energy milestone. Low-carbon electricity—defined as renewables plus nuclear—accounted for approximately 64–65% of total generation [1][2]. Within that total, renewable energy alone supplied between 47% and 52.5% of UK electricity, depending on the source and accounting methodology used [1][3][4]. The variation reflects different data scopes: some sources measure generation, others measure supply, and geographic boundaries (UK-wide versus Great Britain) also affect reported figures.

Wind energy remained the dominant renewable source, contributing around 30% of the total electricity mix [1][3]. Solar power saw substantial growth in 2025, though members disagreed on the precise share—estimates ranged from 6.9% to unspecified growth figures. Nuclear power declined to approximately 11–12% of generation, primarily due to extended maintenance and outages across the aging reactor fleet [1].

A historic milestone was reached in 2025: it was the first full calendar year with zero coal-fired electricity generation in the UK, following the closure of the last coal plant in late 2024 [1]. Fossil gas remained a significant grid balancer, accounting for roughly 27–32% of generation. On specific high-renewable days, the grid achieved near-total clean operation; one widely reported record occurred on 1 April 2025, when low-carbon sources met 97.7% of demand during a half-hour window [1]. The consensus across sources is that 2025 represented a record year for UK clean energy, though exact percentage shares depend on whether the question focuses on renewables alone (47–52.5%) or includes nuclear (64–65%).