In early October 2025, the energy research organisation Ember released data showing that renewable electricity generation overtook coal for the first time in recorded history. Analysts examined monthly electricity statistics from 88 countries, which represent 93% of global demand, and estimated the remaining production to create a comprehensive global picture. They discovered that electricity demand rose by 2.6% during the first half of 2025, an extra 369 TWh (Terawatt-hours) compared with the same period in 2024.
The key factor was the extraordinary surge of solar and wind power, which together supplied enough energy to meet the entire increase in demand – and more. Solar output expanded by 31% year‑on‑year, adding 306 TWh to the global electricity supply, while wind generation increased by roughly 7%. Due to this growth, renewables (including solar, wind, and other sources such as hydro and biomass) generated 5,072 TWh in the first six months of 2025, a huge 4,709 TWh increase from the same period in 2024.
What the numbers revealed:
Renewable vs coal output: Coal‑fired generation produced 4,896 TWh in the first half of 2025, 31 TWh less than the previous year. By contrast, renewables produced 5,072 TWh, outstripping coal for the first time. Fossil‑fuel generation as a whole (coal and gas) declined by 0.3% or 27 TWh, causing power‑sector emissions to fall modestly by 0.2%.
Solar’s dominance: Solar energy met 83% of the additional electricity demand. Falling costs have made solar panels accessible even in lower-income countries; analysts note that module prices have decreased by an incredible 99% since the 1970s, allowing households in Pakistan and across Africa to install rooftop solar panels.
Future outlook: The International Energy Agency (IEA) estimates that global renewable capacity could more than double by 2030. Carbon Brief summarises the IEA’s forecast of about 4,608 GW of additional renewable capacity being installed this decade, even after a downward revision for the United States. Clean energy is now the most cost-effective option for most of the world, and analysts warn that to maintain progress, governments must accelerate investment in solar, wind, and battery storage.
These figures mark a historic transition. For over a century, coal has been the backbone of industrial growth; it still accounts for around one-third of global electricity in 2024. The data from Ember and associated reports show that coal’s dominance is being eclipsed by renewables, partly because solar and wind have become cheaper than new coal plants in most markets and partly because public concern over climate change is driving policy support for clean energy.
Renewables and the UK – Context and Implications
The UK plays a significant role in this shift to cleaner energy. Britain’s last coal‑fired power station, Ratcliffe‑on‑Soar near Nottingham, shut down earlier this year. Renewable sources, led by wind and solar, regularly supply more than half of the UK’s electricity, and the government’s clean energy plan is getting billions of pounds in investment and supporting many skilled jobs. However, we still rely on natural gas for a significant portion of our electricity and most of our heating. Balancing the grid during cold, windless winter weeks remains challenging, as offshore wind output fluctuates and storage is limited. The government intends to increase wind capacity and accelerate offshore projects, but it is also focused on reducing demand through improved insulation and high-efficiency heating appliances.
While headlines celebrate record solar farms and giant offshore wind turbines, another revolution is unfolding inside UK homes. Local space heaters, such as wood-burning stoves, gas fires, and electric fires, serve as primary or supplementary heating sources for millions of households. Their efficiency has improved significantly over the past decade due to eco-design regulations and technological advancements. All key in helping the UK decarbonise.
Ecodesign regulations for local space heaters came into force on January 1, 2018, for gas and electric heaters, and on January 1, 2022, for stoves. These rules, as mentioned frequently in our news articles, set minimum energy-efficiency levels and limit emissions of particulate matter (PM), nitrogen oxides (NOx), organic compounds, and carbon monoxide (CO). These new standards are expected to save up to 78 TWh of energy by 2030, roughly equivalent to Lithuania’s entire primary energy consumption in 2021, and to save consumers over £8 billion annually.
Wood-burning stoves – the growth of sustainable heating
For centuries, open fires were central to British homes, but they are also highly inefficient, as only about 25% of the heat produced actually warms the room. Ecodesign‑ready wood‑burning stoves have changed the picture. These closed stoves must meet minimum net efficiencies of 75% and stringent emission limits. Ecodesign standards reduce allowable carbon monoxide emissions by 88% and particulate emissions by 55% compared to previous requirements.
Improving efficiency also depends on the fuel. UK regulations introduced in 2021 made it illegal to sell bagged house coal or wet wood (wood with a moisture content above 20%). Wet wood burns poorly, wasting energy and releasing significantly more smoke; using properly seasoned “Ready to Burn” wood can reduce emissions by up to 50%. The Ready to Burn certification scheme, operated by HETAS and Woodsure, helps consumers identify compliant fuels. In smoke‑control areas, only stoves exempted by the Department for Environment, Food and Rural Affairs (DEFRA) may be used, further ensuring low emissions.
Gas fires – Still a fossil, but with a plan…
Gas remains our primary heating fuel in the UK. However, while it’s still a fossil fuel, several manufacturers, including us, produce a wide range of gas fires that can also run on hydrogen. Hydrogen-ready gas fires are designed to run on today’s natural gas supply while being prepared for tomorrow’s hydrogen fuel. This means a hydrogen-ready fire can operate on the usual methane gas, but also safely burn a blend of natural gas with hydrogen, typically up to 20% hydrogen mixed with 80% methane, with no modifications. These fires are built so that, with minor adjustments by a qualified engineer, they can be converted to run on 100% hydrogen in the future.
Electric fires – pure efficiency
Electric fires convert nearly 100% of electrical energy into heat at the point of use, making them more efficient than any combustion‑based appliance. Under EU Lot 20 (another component of ecodesign), electric heaters must include thermostats, timers, open‑window detection and adaptive start functions that reduce wasted energy. This ensures the heater turns itself off when a window is open, learns how quickly the room warms up and avoids overheating. For small rooms or short-term use, a 1–2 kW electric fire can be a more cost-effective and environmentally friendly option than running a central heating system, especially as the grid becomes cleaner.
The environmental benefits of electric fires depend on the origin of the electricity. When the grid is supplied by renewable energy, as is increasingly the case in the UK, electric heaters produce no on‑site emissions. In countries where coal still dominates, electric fires may indirectly contribute to more emissions than high-efficiency gas stoves. As the global shift towards renewables accelerates, electric fires will become an increasingly sustainable option.
Energy efficiency is not solely a function of technology; user behaviour matters. Many gas and electric fires now come with smart thermostats that allow users to schedule heating, set temperature zones and monitor consumption via smartphone. EU and UK regulations require that appliances display clear energy labels, enabling consumers to easily compare their performance. Proper installation and regular maintenance of stoves and flues help prevent leaks and improve combustion efficiency. For wood-burning stoves, storing logs under cover and allowing them to season ensures high burn efficiencies. Combining these practices with improved home insulation, zone-heating and draught‑proofing further reduces energy demand.
Linking your household efficiency to the global renewable revolution
The milestone of renewables surpassing coal is not just about giant turbines or vast solar parks; it is also about millions of small decisions made in homes and businesses. Electricity demand is expected to surge as countries electrify their transport and heating systems, yet Ember’s data show that solar and wind can keep pace with growing demand. However, to minimise the strain on grids and avoid resorting to fossil fuel backup, demand-side measures must complement supply-side investment.
Efficient space heaters play a key role in this balancing act:
Reducing peak demand: On cold winter evenings, households often switch on electric heaters simultaneously, creating spikes that must be met by fossil peaking plants. Smart thermostats and high-efficiency appliances smooth these peaks by preheating rooms when renewable energy output is plentiful and reducing consumption during shortages.
Lowering overall energy consumption: An 11% improvement in electric heater efficiency and an 8% improvement for non-electric heaters by 2030 translates into many terawatt-hours saved. Every terawatt‑hour not consumed is a terawatt‑hour that does not need to be generated, stored or transmitted.
Enhancing resilience: Gas and wood stoves provide backup heating during power outages or periods of low renewable energy. Using efficient models reduces fuel requirements and emissions, making them compatible with net‑zero strategies.
Conclusion:
The news that renewable energy has overtaken coal marks a watershed in the history of the global energy system. It confirms that with the right policies and technologies, clean power can meet rising demand. Yet this achievement is not the end of the journey. Gas and coal still supply roughly half of global electricity, and the transition could stall without continued investment, supportive regulation and attention to energy efficiency.
High-efficiency space heaters exemplify the importance of demand-side management. Modern wood-burning stoves burn dry logs cleanly at over 80% efficiency; balanced-flue gas fires provide flexible heat with lower emissions; electric fires turn nearly all their energy into warmth and come with smart controls. Ecodesign standards in the UK are driving these improvements, promising many terawatt‑hours of energy savings and billions of pounds in consumer benefits. By embracing these technologies and using them wisely, households can reduce their carbon footprint, lower their bills, and ease the pressure on national grids.
