Solar surpasses nuclear power globally for first time

The World Nuclear Industry Status Report (WNISR) 2026, overseen by French nuclear energy consultant Mycle Schneider, shows that wind power alone surpassed nuclear generation on a monthly basis in March 2025, followed by solar in April – the first time global monthly solar generation exceeded nuclear output.

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.

Increasing gap

According to the report, the gap between renewables and nuclear widened substantially in 2025. Global solar capacity increased by 510 GW to 2,383 GW, up 27% year on year, while wind added a record 159 GW to reach 1,291 GW, an increase of 14%. By comparison, 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, while wind and, particularly, solar have expanded rapidly.

The report’s PV figures, however, are based on relatively conservative estimates. More recent data from IEA PVPS indicate that global PV additions reached around 690 GW in 2025, about 180 GW more than the figure used by WNISR. This suggests the gap between solar and nuclear capacity – and their respective growth rates – was even wider than indicated in the report.

“The reality of the nuclear industry on the ground is quite sobering for those who expected to find a booming sector,” Schneider told pv magazine. “Recently, U.S. nuclear company Holtec put an initial public offering (IPO) on hold just days before its planned stock market listing, through which it had hoped to raise almost $1 billion. Its peer, Fermi, has lost about 80% of its stock value since it was first listed in October 2025.”

“The main reason? These companies have little or nothing to show on the ground to convince investors to continue providing cash,” he added. “Meanwhile, the world’s operating nuclear fleet increased output by 1.1% – with output declining outside China – while global solar power generation jumped by a stunning 30%, surpassing nuclear’s annual electricity production for the first time. One is tempted to say: It’s the growth rates, stupid!”

The report identifies falling battery costs as a potential enabler of continued PV expansion, particularly as grids contend with growing volumes of variable renewable generation and periods of low or negative electricity prices. Grid-scale battery deployment accelerated sharply in 2025, with 104 GW and 257 GWh connected during the year. More than 78% of cumulative battery energy storage system (BESS) capacity was installed between 2023 and 2025.

Slow expansion

The report shows that the global nuclear sector is expanding slowly, with most new activity concentrated in China and Russia. As of July 1, 2026, 411 reactors were operating in 31 countries, excluding 30 units in long-term outage, with operating capacity at 374.7 GW. In 2025, nuclear plants generated 2,703 TWh, up 1.1% year on year, largely driven by a 7.6% increase in China. Outside China, nuclear generation declined by 0.2% and remained well below its 2006 level. Nuclear’s share of global electricity generation slipped to 8.8%, its lowest level in four and a half decades and roughly half its 1996 peak of 17.5%.

Four reactors started supplying electricity in 2025, while seven closed, resulting in the first negative annual reactor balance since 2021. Between 2006 and 2025, 104 reactors started up and 106 closed. China accounted for 53 of those startups and no closures, meaning the rest of the world recorded a net decline of 55 reactors. Although global nuclear capacity increased by a net 21.5 GW over the two decades, China alone added 52.3 GW, while capacity outside the country fell by almost 30.7 GW.

The construction pipeline has nevertheless expanded. Seventy-three reactors were under construction as of July 1, the highest number since 1987, with China accounting for 37. Russia remains the dominant international supplier, with Russian technology involved in 29 reactors under construction worldwide, including 22 outside Russia. Nine out of 10 reactors being built are in Asia or Eastern Europe.

Long construction times and delays remain a feature of new nuclear projects, according to the report. None of the 16 reactors connected to the grid between 2023 and 2025 was completed on schedule, with an average construction period of 10.9 years. Of 13 reactors scheduled to start generating electricity in 2025, only four did so. Some projects have experienced exceptionally long timelines, including Slovakia’s Mochovce-4, where construction began more than 40 years ago, and Iran’s Bushehr-2, where construction originally started in 1976.

Construction starts accelerated in 2025, however, reaching 12 units, the highest annual total since 2010. Nine were in China, two in Russia and one in South Korea. Of the 52 reactor construction starts recorded worldwide between 2020 and 2025, all but one involved the Chinese or Russian nuclear industries, either domestically or abroad.

Limited progress on small modular reactors

The report questions whether small modular reactors (SMRs) can deliver on their long-standing commercial promises, noting that progress remains limited despite growing government support and public funding.

“For decades, small modular reactors have been held out as holding great promise for expanding nuclear power into various new markets. Remarkably similar claims have been made by the nuclear industry in multiple countries. Nowhere have these claims come true,” the authors said.

The authors challenge several claimed advantages of SMRs, including lower costs, modular construction, improved safety, reduced waste and easier siting. Many commercially proposed designs are 300 MW or larger, while an analysis cited in the report suggests some SMR designs could generate between two and 30 times more nuclear waste than larger reactors.

The report also questions whether modular manufacturing can achieve economies of scale without a large and predictable market. Still, SMR projects are advancing in several countries. Canada began construction of GE-Hitachi’s BWRX-300 in 2026, while China continued testing its Linglong One demonstration reactor. Russia is developing floating and land-based SMRs, while the Czech Republic and Sweden are pursuing Rolls-Royce projects. The report questions whether the EU can meet its goal of deploying its first SMRs by the early 2030s.

The United Kingdom has committed £2.6 billion ($3.5 billion) to advance three Rolls-Royce reactors at Wylfa, with a final investment decision expected in 2029. At 470 MW, the design exceeds the commonly used 300 MW threshold for SMRs.

In the United States, federal funding supports projects involving GE Vernova, TerraPower, X-energy and Kairos Power. While some have reached permitting or construction stages, many remain years from commercial operation. Overall, the report says SMR development remains heavily dependent on public funding, while commercial deployment, construction timelines and the claimed benefits of modular construction remain uncertain.

Global overview

The report also provides detailed country-level assessments covering developments in major nuclear markets and potential newcomer countries, as well as nuclear decommissioning, the Fukushima disaster and Russia’s nuclear interdependencies.

These sections examine reactor operations, newbuild plans, closures, policy developments and the challenges associated with aging fleets. The report also tracks the dismantling of closed reactors, developments in Japan 15 years after the Fukushima accident, and the nuclear industry’s continuing technology, fuel and supply-chain links with Russia.