By Gavin Maguire
LITTLETON, Colorado, Dec 30 (Reuters) - For supporters of the energy transition, 2025 had plenty to complain about: the scrapping of U.S. clean energy policies, wind droughts in Europe,
corporate retreats from wind power generation and a resurgence in coal-fired power output.
Yet there were also developments to celebrate, including record deployment of battery storage systems, historic power generation shares from solar farms in dozens of countries, and continued growth in electric vehicle sales in key car markets.
Below are eight charts that capture some of the key milestones and developments impacting global energy transition progress in 2025, as well as key data points to track heading into 2026 and beyond.
CHINA'S GROWING CLEAN CLOUT
China remains at the forefront of clean energy generation, and deploys more nuclear, solar, wind and bioenergy power than any other nation.
Clean electricity production is on track to record its seventh consecutive year of strong growth. Over the first 11 months of 2025, total clean power output rose 15.4% from a year earlier, Ember data shows.
Clean power sources will generate more than 40% of China's utility-supplied electricity for the first time in 2025, while fossil fuels' share will drop to a record low.
Fossil fuels remain the primary pillar of China's power system, but since 2019 clean power output has grown more than four times faster than fossil-fuel generation.
With Beijing set to keep expanding its solar, wind, nuclear and battery power capacity over the coming decade or so, clean power's share in China's generation mix is likely to keep climbing.
China is also making its mark overseas via record clean-technology exports, which climbed to more than $180 billion over the first 10 months of 2025, according to customs data compiled by Ember.
Battery storage systems have emerged as China's most lucrative clean-tech export, with nearly $66 billion in sales, followed by around $54 billion in EV exports.
Exports of grid equipment and heating and cooling units have also hit record highs in 2025, cementing China's role as the dominant supplier of hardware for the world's electrification push.
U.S. SETBACK
In contrast to China's momentum, U.S. clean energy progress hit reverse in 2025 after federal support for renewables was scrapped under the second administration of U.S. President Donald Trump.
Steep cuts to tax credits for power developers are expected to slash clean energy investments in coming years and leave the U.S. power system heavily dependent on fossil fuels.
Natural gas remains the main source for U.S. electricity, but in 2025, coal-fired plants delivered the biggest jump in output, driven largely by a spike in gas prices that squeezed utility margins.
Coal-fired electricity output from January to November increased 13% from a year earlier, its highest in three years, according to Ember.
Because coal plants emit far more carbon dioxide than gas plants - over 900,000 metric tons of CO2 per terawatt hour versus about 550,000 tons for gas - U.S. power-sector emissions also climbed in 2025.
Total emissions from coal and gas plants reached 1.526 billion metric tons of CO2 from January to November, up 3% from the same period in 2024 and the highest since 2021, Ember data shows.
Given that U.S. natural gas prices look set to finish 2025 at roughly 50% above their 2024 average, utilities are likely to lean further on cheaper coal to meet winter demand.
That means even higher power-sector pollution heading into 2026 and beyond.
BATTERY BOOM AND STEALTHY PROGRESS
Even as U.S. utilities burned more coal in 2025, they also rolled out record battery storage capacity to capture surplus solar and wind power for later use.
Total U.S. installed battery storage capacity surpassed 39 gigawatts in 2025, a 43% increase from 2024, according to energy data portal Cleanview.
That surge is reshaping power flows in key electricity networks. Both California and Texas have added enough battery capacity to materially alter their power grid's generation mix during peak demand.
The California Independent System Operator (CAISO), the state's main grid and the country's largest battery adopter, uses batteries to supply around 15% to 18% of electricity during the evening peak demand, according to Grid Status data, reducing the need for gas and other power sources.
In the Electric Reliability Council of Texas (ERCOT), a more recent adopter of battery systems, around 3% of electricity during peak demand was supplied from battery storage systems - a modest share but up from near zero just a year ago.
Solar power systems have also made their mark again in 2025, generating record shares of utility electricity supplies in several countries.
China and the U.S. typically dominate discussions about solar capacity, but solar's widespread penetration in recent years now means that developed and emerging economies alike deploy the technology at scale.
At times in 2025, countries such as Bulgaria, Pakistan, Hungary and Poland sourced around 20% or more of their electricity from solar farms, cutting both costs and emissions.
In 2026, solar's generation share will likely set new records in even more countries, helping to keep global energy transition momentum alive even if some major economies, such as the U.S., step back.
The opinions expressed here are those of the author, a columnist for Reuters.
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(Reporting by Gavin Maguire; Editing by Marguerita Choy)
