European governments have been planning a major expansion of nuclear power as part of their strategy to fight climate change and meet rising electricity demand. This summer, that plan collided with the very problem it is meant to solve.
Nuclear power has become central to net zero plans across the continent, with governments viewing it as a reliable, low carbon complement to wind and solar generation. But nuclear reactors need large amounts of water for cooling, most of it drawn from rivers. In August, heat waves and worsening drought pushed river levels in parts of Europe to record lows, leaving some plants with less of the water they depend on to keep reactors cool.
This is not a new phenomenon. European utilities have periodically had to reduce output or pause reactors during past heat waves when river temperatures rose too high or flows dropped too low, a pattern that has become more frequent as summers have grown hotter. What is new is the scale of the buildout now planned across the continent, which raises the stakes for how utilities and regulators adapt reactor design, cooling systems, and siting decisions to a climate that is expected to keep warming.
The episode highlights a broader tension facing energy planners worldwide: technologies chosen to reduce the effects of climate change can themselves be vulnerable to the changing climate they are meant to help address. For nuclear power specifically, that means water availability is becoming as important a planning consideration as reactor safety and construction cost.
Energy ministries and utilities across Europe are expected to review cooling infrastructure and siting standards for new reactors in light of this summer's experience.
Why do nuclear plants need river water?
Most nuclear reactors rely on water drawn from rivers or other bodies of water to cool their systems, and that supply can shrink during droughts or heat waves.
Is this the first time this has happened in Europe?
No, European utilities have had to scale back reactor output during past heat waves, but the trend has become more frequent as summers grow hotter.