With five years of blackout records from 36 countries laid out, no sign appeared that countries which expanded solar and wind lose power more often. That is the conclusion of a report released on the 23rd by Refact, a renewable energy fact-checking platform. The report rated the widespread claim that "expanding renewable energy causes major blackouts" as "mostly false."
The analytical tool was the System Average Interruption Duration Index (SAIDI) compiled by the World Bank. The index shows how many hours the average consumer spent without power over a year, and changes in 36 OECD member countries from 2015 to 2019 were compared with changes in their share of renewable energy.
The results did not tilt to one side. Of the 32 countries whose share of renewable generation rose during the period, 17 (53.1%) saw their outage times get shorter. The United Kingdom, Japan, France, Hungary and Estonia are among them. Countries where outage times grew longer numbered 13 (40.6%), including the United States, Ireland, the Netherlands and New Zealand, and two countries, South Korea and Germany, showed no change.
Looking at individual cases shakes the conventional view once more. Lithuania pushed its renewable share up by 28.15 percentage points over five years, and its outage time rose by 36 seconds (0.01 hours). Switzerland, on the other hand, cut its renewable share by 3.26 percentage points and still saw outage time grow by about three minutes (0.06 hours).
So why did the actual major blackouts happen? When the international research institute Zero Carbon Analytics (ZCA) took apart 20 major blackouts around the world from 2005 to 2025, the most frequent cause was infrastructure faults including aging equipment, at 11 cases. Human error followed with 6 cases, natural disasters and extreme weather with 5, and lack of investment with 4. Cases in which grid overload or instability was named came to just 3.
The Iberian Peninsula case standing at the center of the debate is the same. The European Network of Transmission System Operators (ENTSO-E) issued a final investigation report on the blackout that struck Spain and Portugal last April, and the voltage rise that pulled the trigger was not explained by a single cause. The investigation team said 14 factors, including insufficient reactive power delivery, gaps in dynamic voltage control standards and the instability of inverter-based facilities, became tangled together and worked at once.
The road Spain took was not a retreat. The government carried its renewable expansion policy forward as it was, while reworking the relevant rules so that renewable power plants take charge of dynamic voltage control services. The buildout of capacity did not slow down either. Between May 2025 and February 2026, after the blackout, wind and solar were added at a monthly average of 1.3GW, a figure above the monthly average of 1.2GW in the year just before.
Some point out that the flow of the world's power capacity has itself tilted that way. Hwang Min-soo, a research fellow at the Energy Technology Research Association, said 85.6% of the generation capacity newly built around the world in 2025 was renewable. The point is that while the argument runs over generation sources, what actually needs fixing is the grid that takes in and carries that electricity and the market rules that move it. Jeon Young-hwan, a professor in the Department of Electronic and Electrical Engineering at Hongik University, took part in reviewing the report.
The power grid is not easy to see. Substations and transmission lines are mostly outside the cities, and no one calls their names until they break down. The next time news of a major blackout arrives, before suspecting the generation source first, it is worth looking up a single line on how much aging equipment that country replaced over the past decade. Most of the answer is written in that line.
