The renewed attention to nuclear energy is often described as a "comeback".
This framing is misleading. Nuclear power is not returning because preferences have shifted or because the political narrative has softened. It is returning because thedegrees of freedom of the energy system are narrowing.
TheWorld Energy Outlook 2025published by the International Energy Agency at the end of 2025 makes this dynamic increasingly visible.Global energy demand continues to grow, driven primarily by emerging economies, while electricity consumption is projected to rise sharply as transport, industry and digital infrastructures electrify. This acceleration is taking place in a context of mounting climate constraints and growing exposure of power systems to physical, operational and cyber risks.
For much of the past two decades,the energy transition debate has assumed that expanding renewable capacity, complemented by fossil fuels as a bridge, would be sufficient to ensure both decarbonization and system stability. That assumption is now under strain. Variable renewables are expanding rapidly, but their intermittency creates rising demands for balancing capacity, grid reinforcement and storage. Oil and gas continue to play a stabilizing role in the short and medium-term, yet their long-term compatibility with climate objectives is increasingly limited.
This combination produces a structural tension.As decarbonization advances, firm, dispatchable capacity becomes harder to replace. Without low-carbon baseload, power systems rely more heavily on fossil backup or on large-scale deployment of technologies that remain uncertain in cost, scalability and public acceptance.
It is within this narrowing corridor that nuclear energy re-enters the debate. Not as a silver bullet, but as asystem stabilizer. Nuclear power offers continuous, low-carbon electricity, reduces dependence on fossil fuels for balancing, and limits exposure to volatile fuel markets and geopolitically sensitive supply chains.
This reassessment is reflected in current projections.After more than two decades of stagnation, global nuclear capacity is expected to increase significantly by the mid-2030s, with expansion driven both by lifetime extensions and new build projects. According to the World Nuclear Association, stated national commitments could lead to a tripling of global nuclear capacity by 2050, supported by renewed investment in large-scale reactors and the development of small modular reactors designed to respond to different market and system needs.
The risks associated with nuclear energy remain well known: high upfront costs, regulatory complexity, waste management and societal acceptance in front of the slight but existing possibility of a serious incident.What is changing is the perception of the alternative risks.Underinvestment in firm capacity (power that is reliably available when the system needs it, not just when conditions are favorable) increases exposure to price volatility, system disruptions and credibility gaps between climate objectives and actual outcomes.
The nuclear debate is therefore shifting. It is about whether an increasingly electrified energy system, operating under geopolitical fragmentation and climate stress, can remain reliable without sufficient firm, low-carbon capacity.