Record year for wind and solar electricity in Great Britain in 2025.

Great Britain’s electricity grid witnessed a landmark transformation in 2025, with renewable energy sources achieving an unprecedented level of output, according to a comprehensive analysis by the BBC. These green technologies, vital for mitigating climate change, collectively generated a record amount of electricity, underscoring the nation’s accelerating shift towards a cleaner energy future.

Provisional figures released by the National Energy System Operator (Neso) highlight wind power as the dominant renewable contributor, maintaining its position as the largest single source of green electricity. However, the most striking development was the substantial surge in solar-powered electricity, which saw an increase of nearly a third compared to 2024 levels. This remarkable growth was significantly bolstered by Great Britain experiencing its sunniest year on record, coupled with a notable expansion in solar panel installations across the country, from vast solar farms to countless rooftop arrays.

Despite this impressive renewable boom, the data also revealed a slight, albeit concerning, uptick in electricity generated from fossil gas. This highlights the persistent challenges facing the government as it strives to meet its ambitious "clean power" target by 2030, which aims to virtually eliminate polluting gas from electricity production.

"It has been quite a strong year in terms of deployment of renewables," observed Pranav Menon, a research senior associate at the influential Aurora Energy Research think tank. Menon elaborated on the dual nature of the progress, acknowledging the significant strides made while also pointing out the scale of the remaining task. "[But] what we’re not seeing is kind of the exponential scale-up that you’d need to get to clean power 2030, because those targets are very, very ambitious," he added, emphasizing the urgency required to accelerate the transition further.

The government’s "clean power" target mandates that 95% of all electricity generated in Great Britain should come from renewables and nuclear energy by the end of the decade. This ambitious goal is not solely driven by environmental imperatives; it is also closely linked to a promise to reduce household energy bills by up to £300, with clean power posited as a key mechanism to achieve this by decoupling energy prices from volatile international fossil fuel markets. It is important to note that Neso data and the government’s clean power target specifically cover Great Britain, excluding Northern Ireland, which operates its own distinct electricity transmission system.

The global trend of rapid renewable energy growth has been a beacon of hope in the fight against climate change, and Great Britain has been a significant part of this narrative over the past decade. The government’s intent to further accelerate renewable deployment is central to both its clean power goal and its broader commitment to reducing planet-warming carbon emissions.

In 2025, the combined output from wind, solar, hydro, and biomass sources surpassed all previous records, generating more than 127 terawatt hours (TWh) of electricity. This figure, derived from the BBC’s analysis of provisional Neso data, comfortably exceeds the previous high of 119 TWh recorded in 2024, illustrating a consistent upward trajectory in green energy production. The accompanying chart, showing the total amount of electricity generated from renewable sources from 2009 to 2025, visually confirms this trend, with a steep climb from a mere 9 TWh in 2010 to the current record.

Wind power continued to be the backbone of Great Britain’s renewable energy mix, delivering over 85 TWh of electricity. This accounted for nearly 30% of the nation’s total electricity supply, a slight increase on its 2024 contribution. The continued expansion of both onshore and offshore wind farms, coupled with favourable wind conditions throughout the year, contributed to this robust performance. New offshore projects, such as those in the North Sea, have been instrumental in bolstering capacity and reliability.

However, the spotlight in 2025 truly belonged to solar power. Over the course of the year, solar panels across Great Britain generated more than 18 TWh, contributing over 6% to the national electricity grid. While still a smaller share compared to wind, this represents a substantial growth of more than 4 TWh over 2024 figures. The impact of solar was particularly evident during peak periods, with certain half-hour intervals in July seeing solar panels supply over 40% of the electricity demand. This is a dramatic contrast to 2013, when solar rarely exceeded 5% of total generation at any given time, as vividly depicted in the two-section chart illustrating solar’s daily contribution over the years. The deepening orange shading in the summer months of 2025 compared to earlier years underscores this significant progression.

Several factors converged to drive this solar boom. The expansion of solar panel installations across the UK continued apace, with new large-scale solar farms coming online. Notable among these was the activation of the biggest solar farm yet, located at Cleve Hill near Faversham in Kent, significantly boosting grid-connected capacity. Simultaneously, 2025 marked a record year for small-scale solar installations, with approximately 250,000 new rooftop systems reported to the Microgeneration Certification Scheme, reflecting a growing consumer appetite for self-generated power. These infrastructure developments were perfectly complemented by the weather: 2025 was officially recognised as the UK’s sunniest year on record, providing ideal conditions for British solar panels to maximise output during the extended daylight hours of spring and summer.

Professor Michael Grubb, an expert in energy and climate change at University College London, commented on this phenomenon: "Solar’s probably a bigger part of the system than we’d expected, given the cost has come down so much." He highlighted the economic viability that has made solar an increasingly attractive and accessible option for both large-scale developers and individual homeowners.

The increasing reliability and capacity of renewables meant that on roughly a third of days in 2025, at least half of Great Britain’s electricity demand was met by green sources. The tile chart, which shades each day from 2009 to 2025 based on the percentage of renewable electricity generated, clearly shows a dramatic shift, with far more days in recent years hitting the dark green threshold of 50% or more. This illustrates the growing capability of the grid to integrate high proportions of intermittent renewable energy.

However, the British electricity grid continues to rely significantly on fossil fuel gas, particularly when renewable output is low. Analysis of Neso’s figures indicates that gas-fired power stations generated over 77 TWh of electricity in 2025, accounting for approximately 27% of the total supply. This represents an increase from 72 TWh in 2024, a trend that poses a significant hurdle to decarbonisation efforts.

Several interconnected factors likely contributed to this rise in gas generation. Great Britain imported slightly less electricity from European interconnectors in 2025, possibly due to higher demand or operational issues within the European market. Concurrently, nuclear generation experienced a dip, potentially due to scheduled maintenance outages or the phased decommissioning of older plants. Furthermore, the closure of the last remaining coal power station in 2024, a significant milestone in decarbonisation, meant that gas often filled the gap previously supplied by coal when renewable output was insufficient. Finally, an overall increase in electricity demand across Great Britain, driven by economic growth and early stages of electrification in heating and transport, also necessitated a greater contribution from readily available, dispatchable power sources like gas.

Consequently, the carbon intensity of Great Britain’s electricity supply saw a slight increase in 2025 compared to the previous year. Each kilowatt-hour (kWh) of electricity generated, on average, 126 grams of planet-warming carbon dioxide, up from 124g/kWh in 2024. While this marginal rise is a setback, it is crucial to place it in historical context: the 2025 figure represents a dramatic reduction from the 505g/kWh recorded in 2012, demonstrating the profound decarbonisation achieved over the last decade and a half. The area chart, depicting the proportion of electricity generation by fuel source from 2009 to 2025, vividly illustrates this transition, showing a significant decline in coal and gas and a corresponding increase in renewables.

It is worth noting that Neso’s figures, with the exception of wind and solar, primarily cover generation connected to the main transmission network. They do not fully encompass smaller-scale gas, biomass, and hydro operators that feed electricity into the local distribution networks. However, these smaller sources contribute a relatively minor fraction to Great Britain’s overall electricity generation. Separate analysis of UK government data by the climate website Carbon Brief, which includes these smaller sources and also incorporates Northern Ireland’s figures, corroborates the trends identified in the Neso data for Great Britain, confirming both the new renewables record and the slight increase in gas generation.

Off track for clean power?

The government’s "clean power" target, aiming for 95% of electricity from renewables and nuclear by 2030, appears increasingly challenging in light of the 2025 figures. In 2024, clean sources accounted for almost three-quarters of total electricity generation, according to government statistics. While official government figures for 2025 will not be released until later this year, the persistent presence and even slight increase of gas in the electricity mix underscore the significant work still required to meet the target.

"There’s still a significant number of periods in the year where the sun’s not shining, the wind’s not blowing, demand is high […] and that’s where the system is sort of forced to rely on gas-fired power to turn up and meet demand," Pranav Menon reiterated. He stressed that technological solutions are readily available to address this intermittency. These include large-scale battery storage facilities, which can store excess renewable electricity during periods of high generation for use when conditions are less favourable, and other low-carbon, dispatchable sources like nuclear power, which offer a consistent and reliable base load.

Another formidable obstacle to achieving the clean power target is the pressing need for extensive upgrades to the national electricity grid. These upgrades are essential not only to connect new renewable energy projects, particularly in remote areas with high wind or solar potential, but also to efficiently transmit their electricity across the country to demand centres. Currently, grid bottlenecks and capacity limitations sometimes mean that the system cannot accommodate all available renewable electricity. This leads to the costly practice of "curtailment," where wind farms, for example, are paid to reduce their output even when generating capacity is high, effectively wasting clean energy.

While grid upgrades are designed to alleviate these issues and enhance network resilience, they represent significant investments that add to costs in the short term. Professor Grubb acknowledged this trade-off, noting that "upgrades add to costs in the short term," which "could offset some of the savings from some of the cheapest renewables which are starting to displace gas power." Despite these challenges, he expressed optimism that energy bills would begin to decrease in the coming years, primarily due to the increasing deployment of cost-effective renewables and an anticipated stabilisation or reduction in international gas prices from their recent high levels.

The provisional data for 2025 sparked immediate political reactions. Energy Secretary Ed Miliband lauded the progress, stating: "After years of delay and underinvestment, this government is keeping its promise to take back control of Britain’s energy with clean homegrown power." He emphasised that this strategic shift would "protect households against volatile fossil fuel markets," securing a more stable and affordable energy future for the nation.

Conversely, Shadow Energy Secretary Claire Coutinho called for the government to reconsider its clean power target, arguing that its pursuit was contributing to rising energy bills. "Britain is generating more renewable power than ever before, but people should know about the extra costs that come along with it," she asserted, highlighting the ongoing debate about the economic implications and financing mechanisms for the energy transition.

The record year for wind and solar electricity in Great Britain in 2025 undeniably marks a significant milestone in the journey towards decarbonisation. It demonstrates the immense potential of renewable technologies and the capacity of the grid to integrate substantial amounts of green power. However, the persistent reliance on fossil gas and the formidable infrastructure challenges underscore that while much has been achieved, the path to a fully clean and secure energy system by 2030 remains a complex and demanding endeavour.