Record solar output is helping to shield Hungary's power system from the worst effects of the forced cutbacks at the country's only nuclear power plant, demonstrating that renewables can provide a critical layer of resilience in power systems.
Output from the Paks reactors so far in August is down by more than 80% from July's average, data from LSEG showed, placing heavy strain on the East European economy's power grid.
However, thanks to record-high output from solar farms that is up nearly 20% year-over-year in August, total power output is down less than 3% compared to average.
The solar contribution is preventing blackouts while reducing both electricity imports and fossil fuel that would otherwise make up the nuclear shortfall.
The episode is highlighting how renewable energy has become a way to increase reliability as well as a source of clean power, giving electricity systems a crucial buffer when conventional generators are forced to cut output.
RUNNING DRY
The Paks reactor is one of several European nuclear plants that have been affected by drought and heatwaves this year.
The Kozloduy Nuclear Power Plant, which provides around 35% of Bulgaria's electricity needs, has also been forced to cut capacity, while several reactors in France — Europe's top nuclear power producer — have also had to reduce generation as cooling water became scarce.
The Paks plant in Hungary faced a critical situation earlier this month as water levels on the Danube plumbed historic lows of less than 1 foot (30 cm) in areas near Budapest, according to data from LSEG.
However, emergency engineering work to boost river levels near the plant helped avert a complete reactor shutdown, and as of Wednesday two turbines continued to operate at the plant.
SOLAR SAVE
Output from the Paks nuclear plant has tumbled from an average of around 1,700 megawatt hours per hour (MWh/h) from January through July to around 312 MWh/h so far in August due to the cooling water shortages, LSEG data showed.
That nearly 82% plunge in production would normally trigger massive Hungarian electricity imports as well as steep increases at Hungarian power plants that burn gas and coal.
This year, however, sustained high production from Hungary's solar farms, supplemented by the country's fast-growing battery energy storage capacity, have kept overall electricity output levels largely steady.
Solar production during August has so far averaged around 1,418 MWh/h, which compares to an average of around 1,150 MWh/h in August 2025 and around 925 MWh/h for the first seven months of the year.
That solar swell has allowed solar plants to account for a record-high share of more than 55% of Hungary's generation mix at times this month, just as nuclear's share of the power mix fell from its long-term average of around 50% to less than 10%.
Of perhaps equal importance is the lesson that has come from solar's enhanced status within Hungary's power mix: That renewables can offer system-saving stability when conventional generation sources fail.
As drought has curtailed the country's largest source of electricity, solar is proving to be far more than an emissions-cutting technology. It is proving to be a dependable source of backup when the system needs it most.
And as drought increasingly constrains nuclear generation across Europe, other power systems may find in Hungary's solar experience a compelling example of how renewable energy can help safeguard electricity supplies when traditional sources come under stress.
The opinions expressed here are those of the author, a columnist for Reuters.
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