Solar Surpasses Nuclear Power Globally For First Time

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Solar generation exceeded nuclear power globally for the first time in 2025, according to the World Nuclear Industry Status Report 2026. The report says solar output rose 30%, while nuclear generation increased 1.1%; monthly data show solar or wind individually outproduced nuclear in every month from March 2025 through June 2026.

Solar power generated more electricity than nuclear globally in 2025, the first time it has overtaken nuclear on an annual basis, according to the World Nuclear Industry Status Report 2026. The report says solar output jumped 30% while nuclear generation rose 1.1%, underscoring how quickly the two technologies are growing at different rates.

The report, overseen by French nuclear energy consultant Mycle Schneider, also tracks the monthly crossover. Wind generation exceeded nuclear in March 2025, followed by solar in April, the first month when global solar output was higher. From March 2025 through June 2026, either wind or solar individually generated more electricity than nuclear each month. In March, April and May 2026, both wind and solar separately outproduced nuclear.

Capacity figures point to the same divergence, though they measure the ability to generate electricity rather than actual output. WNISR estimates solar capacity grew by 510 gigawatts to 2,383 GW in 2025, a 27% increase, while wind added a record 159 GW to reach 1,291 GW. Installed nuclear capacity rose by 1.5 GW to 399.5 GW, while operating capacity declined by 0.5 GW to 368.6 GW.

The report’s solar capacity estimate is conservative compared with a separate figure from IEA PVPS. That source puts global photovoltaic additions in 2025 at about 690 GW, roughly 180 GW above WNISR’s estimate. The figures are not interchangeable: one is annual capacity added, while the generation comparison concerns electricity produced over time.

Renewables’ Faster Growth Widens the Gap

The crossover matters because it records a change in the global electricity mix, not simply a contest over installed capacity. Solar output grew far more quickly than nuclear output in 2025, while nuclear’s share of global electricity generation fell to 8.8%, its lowest level in 45 years, according to WNISR. That share compares with a peak of 17.5% in 1996.

Rapid growth in solar and wind also increases the need to manage variable production and match electricity supply with demand. WNISR points to falling battery costs and rising storage deployment as factors that could support further solar expansion. It reports that 104 GW of grid-scale battery power capacity, with 257 gigawatt-hours of energy capacity, was connected in 2025. More than 78% of cumulative battery storage capacity had been installed in the three years from 2023 to 2025.

The report’s figures do not show that solar has replaced nuclear or that every electricity system has seen the same shift. They do indicate that, at the global level, annual solar generation has moved ahead while nuclear output has grown more slowly. The relative pace of new construction, project completion and grid investment will affect how the gap develops.

Nuclear Output and Projects in Perspective

Nuclear generation reached 2,703 terawatt-hours in 2025, up 1.1% year on year. WNISR attributes much of the increase to China, where output grew 7.6%. Outside China, nuclear generation slipped 0.2% and remained below its 2006 level. The report says four reactors began supplying electricity in 2025 and seven closed, producing a negative annual balance of three units.

As of July 1, 2026, the report counted 411 operating reactors in 31 countries, excluding 30 units in long-term outage. Its operating-capacity figure for that date was 374.7 GW; this differs from the 2025 capacity measure cited elsewhere in the report because the dates and categories are different. The construction pipeline included 73 reactors under construction, the highest count since 1987, with 37 in China.

WNISR also describes delays as a continuing feature of new nuclear projects. None of the 16 reactors connected to the grid between 2023 and 2025 was completed on schedule, and their average construction time was 10.9 years. Of 13 reactors scheduled to start operating in 2025, four did. At the same time, construction starts rose to 12 in 2025, including nine in China, two in Russia and one in South Korea.

“The reality of the nuclear industry on the ground is quite sobering for those who expected to find a booming sector.”

— Mycle Schneider, overseer of the World Nuclear Industry Status Report, speaking to pv magazine

Estimates and Comparisons Need Care

The reported crossover is based on WNISR’s accounting of global electricity generation. The supplied report does not give a full country-by-country breakdown of the solar-versus-nuclear comparison or explain every data source and adjustment behind the monthly figures. Its PV capacity estimate also differs from the higher 2025 additions figure cited from IEA PVPS, so the scale of capacity growth depends on which dataset is used.

The annual generation comparison should not be confused with capacity totals or with output in individual countries. The report says nuclear generation increased globally in 2025, largely because of growth in China, even as it declined slightly outside China. It does not establish that solar will exceed nuclear in every future year, nor does the source material provide a forecast for when or whether that may happen.

Schneider’s comments about Holtec’s postponed initial public offering and Fermi’s share-price decline are attributed assessments of company and investor conditions. They are separate from the measured global generation figures. The source material does not provide further detail on the causes of either company’s financial developments.

Storage and New Projects Shape the Trend

Future comparisons will depend on whether solar and wind capacity additions continue, how much of that capacity is connected to grids, and how effectively storage and other grid resources balance variable output. WNISR identifies battery deployment as a relevant development, but its 2025 figures alone do not establish how much storage will be added in later years or what effect it will have on electricity generation.

For nuclear, upcoming reactor starts, closures and construction schedules will affect both operating capacity and output. The report’s construction figures show a large pipeline, concentrated in China and, to a lesser extent, Russia, alongside delays among projects due to start operating. The next annual report and updated generation data will clarify whether the 2025 crossover persists and how the capacity and output trends compare.

Key Questions

What did solar surpass nuclear in?

Solar surpassed nuclear in global electricity generation in 2025, according to WNISR 2026. The comparison is about electricity produced, not installed capacity.

When did solar first outgenerate nuclear in a month?

WNISR says global monthly solar generation first exceeded nuclear output in April 2025. Wind had crossed the monthly threshold a month earlier, in March.

Did nuclear generation fall in 2025?

No. Nuclear generation rose 1.1% globally to 2,703 terawatt-hours, according to the report. Output increased in China but declined 0.2% outside China.

How quickly did solar capacity grow?

WNISR estimates solar capacity increased by 510 GW to 2,383 GW in 2025, a 27% rise. IEA PVPS data cited by the report put solar additions at about 690 GW, showing that estimates differ by source.

Does the crossover mean solar will stay ahead?

The report establishes a 2025 annual crossover and a run of monthly comparisons through June 2026. It does not establish how long solar will remain ahead; future output will depend on new capacity, project completion, grid connections and other factors.

Source: hn