According to the World Nuclear Industry Status Report (WNISR) 2026, overseen by French nuclear energy consultant Mycle Schneider, solar power generation surpassed nuclear output on a monthly basis for the first time in April 2025. Wind power had already exceeded nuclear generation in March 2025, marking a historic shift in global electricity production.
From March 2025 through June 2026, either solar or wind individually generated more electricity than nuclear every month. In March, April, and May 2026, both technologies independently surpassed nuclear generation.
The capacity gap between renewables and nuclear widened substantially in 2025. Global solar capacity increased by 510 GW to 2,383 GW—a 27% year-on-year increase—while wind added 159 GW to reach 1,291 GW, an 14% increase. By contrast, installed nuclear capacity rose by just 1.5 GW to 399.5 GW, while operating nuclear capacity declined by 0.5 GW to 368.6 GW. The report notes that nuclear capacity has remained essentially flat for more than 25 years.
The WNISR’s solar figures are based on conservative estimates. More recent data from IEA PVPS indicate global PV additions reached around 690 GW in 2025—approximately 180 GW more than the WNISR estimate—suggesting the actual gap between solar and nuclear capacity was even wider.
Global solar power generation increased by 30% in 2025, surpassing nuclear’s annual electricity production for the first time. By comparison, the world’s operating nuclear fleet increased output by 1.1%, with output declining outside China. Nuclear’s share of global electricity generation slipped to 8.8%, its lowest level in four and a half decades.
The nuclear sector is expanding slowly, with most new activity concentrated in China and Russia. In 2025, four reactors started supplying electricity while seven closed, resulting in the first negative annual reactor balance since 2021. Between 2006 and 2025, 104 reactors started up and 106 closed globally. China accounted for 53 of those startups and no closures, meaning the rest of the world recorded a net decline of 55 reactors.
The report questions the commercial viability of small modular reactors (SMRs) despite growing government support. According to the authors, progress remains limited despite decades of promises, and many claimed advantages—including lower costs and easier siting—remain unproven. The report notes that some SMR designs could generate between two and 30 times more nuclear waste than larger reactors.
Key facts
- Solar generation exceeded nuclear output monthly for the first time in April 2025
- Global solar capacity increased 27% year-on-year in 2025 to 2,383 GW, while nuclear capacity grew just 1.5% to 399.5 GW
- Solar power generation jumped 30% in 2025, surpassing nuclear’s annual electricity production
- Nuclear’s share of global electricity generation fell to 8.8%, its lowest level in four and a half decades
- In 2025, four nuclear reactors started up while seven closed, the first negative annual balance since 2021
- China accounted for 53 of 104 reactor startups between 2006 and 2025, while the rest of the world saw a net decline of 55 reactors