Global solar power surpasses nuclear for first time

Solmar Insights

Solar generation outpaced nuclear on a global scale for the first time in 2025, according to the World Nuclear Industry Status Report (WNISR) 2026. The report identifies a significant divergence in growth rates, with worldwide solar capacity reaching 2,383 GW, while nuclear remained essentially flat at just under 400 GW.

Milestone in global generation

The WNISR 2026 found that both wind and solar technologies independently surpassed nuclear power in terms of monthly electricity generation for the first time. Wind first exceeded nuclear output in March 2025, with solar following in April. Between March 2025 and June 2026, wind or solar outproduced nuclear energy in every month on a global basis. During the spring months of 2026, both wind and solar independently held a generation edge over nuclear simultaneously.

The rapid acceleration in renewable output marks a clear shift in the international generation mix. The transition was highlighted by solar’s robust performance, spurred by falling costs, technology advancements, and market expansion beyond legacy regions. This milestone reveals increasing displacement of nuclear’s share in the global electricity system.

Surge in renewables, stalled nuclear

According to WNISR, global solar grew by 510 GW in 2025, amounting to a 27% increase, while wind added a record 159 GW to hit 1,291 GW in installed capacity, up 14%. By contrast, nuclear added only 1.5 GW that year, reaching a total of 399.5 GW, and operating capacity actually declined by 0.5 GW to 368.6 GW due to retirements and outages.

The report notes that nuclear capacity has held relatively steady for more than 25 years, with marginal increases failing to keep pace with surging renewables. Battery storage was also a key facilitator, as grid-scale storage deployments jumped by 104 GW and 257 GWh in 2025. More than three quarters of cumulative battery energy storage came online between 2023 and 2025, helping integrate solar and wind by buffering variability.

Capacity and generation data revisited

While the WNISR used relatively conservative estimates for global PV expansion, other data sources suggest actual growth was even more robust. The IEA PVPS reported global solar additions topped 690 GW in 2025, about 180 GW greater than WNISR’s figure, revealing an even wider lead over nuclear capacity and output.

For nuclear, the sector faces chronic slow growth and protracted construction timelines. New projects and small modular reactors have yet to meaningfully contribute on a global scale, and sector investment is hampered by delays and financial underperformance. Notably, U.S. nuclear developer Holtec recently postponed its IPO, citing weak investor interest, while peer Fermi’s stock value plummeted 80% since its 2025 debut.

Drivers, challenges, and implications

PV and wind’s rapid growth has been supported by cost declines, supportive policy environments, and increased manufacturing capacity. In contrast, nuclear’s flat trajectory is attributable to high capital expenditure, complex financing structures, and regulatory hurdles, particularly outside China. Nuclear generation posted only a 1.1% output increase in 2025, with actual declines outside China, while solar production climbed an estimated 30% in the same period.

The growing capacity and flexibility provided by grid-scale battery storage is enabling the integration of variable renewables into power systems, further reducing nuclear’s operational advantage. With periods of low or negative pricing becoming more frequent in high renewable penetration grids, storage is mitigating supply-demand imbalances, a dynamic that is expected to intensify as solar and wind continue their expansion.

Reporting via the original publisher