Sizewell’s Exploding Budget Exposes Europe’s Nuclear Blindspot

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The recent announcement that the UK’s Sizewell C nuclear generation construction’s projected cost has doubled from £20 billion in 2020 to nearly £38 billion today is shocking but predictable. For anyone following Europe’s nuclear power saga, such an escalation is not an anomaly but rather a continuation of a deeply entrenched pattern. This project, part of Europe’s broader push for nuclear power to meet climate goals, is again raising fundamental questions about whether European governments and utilities have truly laid the groundwork for successful nuclear power scaling, or if they continue to underestimate the scale of the task.

To assess what has gone wrong, we can turn to a clear set of criteria for successful nuclear programs that history provides. These criteria are based on the best available evidence from nuclear build-outs globally, and importantly, are grounded in repeated successes and failures documented by energy historians and experts. Seven specific factors emerge as crucial: first, nuclear power programs require a strategic national priority with consistent government oversight and support. Second, successful nuclear programs historically have close alignment with military nuclear objectives, benefiting from established skill sets, infrastructure, and strategic imperatives. Third, reactor programs thrive only when standardized around a single, fully proven reactor design. Fourth, large-scale reactors in the gigawatt range provide significant economies of scale. Fifth, there must be a comprehensive, government-supported training and human resources program. Sixth, deployment should be rapid, continuous, and sustained over two to three decades to leverage learning effects. Finally, successful nuclear deployments involve constructing dozens of reactors, not just a few isolated units, to benefit from economies of scale and accumulated knowledge.

Evaluating Europe’s EPR (European Pressurized Reactor) program against these criteria provides a sobering picture. The strategic national priority criterion has only partially been met. European governments have indeed supported nuclear in principle, yet actual oversight has varied considerably, often shifting responsibilities between private entities, state regulators, and multinational utilities, diluting accountability. There has been no consistent, comprehensive governmental stewardship. Each reactor site faces a new web of bureaucratic complexity rather than benefiting from streamlined regulatory oversight.

The second criterion, integration with military objectives, is entirely absent in the European context. Historically, successful nuclear programs like those in France, the United States, or Russia have been intertwined with military nuclear efforts. The absence of military nuclear integration in contemporary European programs removes a critical element of strategic urgency, funding, and workforce stability. Europe’s nuclear effort remains civilian-only, losing these historical advantages.

Standardization of reactor design has also fallen short. Although the EPR was intended to be Europe’s standardized reactor, actual implementations have seen multiple design modifications, extensive site-specific customizations, and evolving regulatory requirements. Each new European EPR has effectively become another first-of-a-kind construction project, losing almost all potential learning curve benefits. The changes between Flamanville in France, Olkiluoto in Finland, and Hinkley Point C in the United Kingdom illustrate starkly how the promise of standardization has not materialized.

While the fourth criterion of large-scale reactors in the gigawatt class is technically met, this alone has not guaranteed success. Indeed, the EPR’s massive scale of around 1.6 GW per reactor, designed specifically to capture economies of vertical scaling, has perversely contributed to complexity and cost overruns due to an insufficiently mature supply chain, workforce, and management capability. Size alone cannot substitute for weaknesses elsewhere in the development ecosystem.

A major factor missing from Europe’s nuclear plans has been a centralized, government-led workforce training and human resource strategy. Nuclear construction is complex and requires extremely well-trained, specialized and security-cleared personnel who work effectively in teams. Europe’s nuclear workforce remains fragmented, project-based, and heavily reliant on temporary contractors. This workforce structure prevents accumulation of essential expertise and institutional memory. By contrast, successful nuclear builds historically, such as France’s 1970s and 1980s fleet or South Korea’s more recent nuclear expansions, relied explicitly on stable, state-backed workforces built over decades.

The sixth factor, rapid and sustained deployment over a defined two- or three-decade timeframe, has been consistently unmet in Europe. Instead, construction schedules stretch over a decade or longer for individual projects, with significant gaps between reactor starts. Olkiluoto took nearly 18 years from groundbreaking to full commercial operation, while Flamanville has similarly ballooned from a five-year schedule to more than 17 years. Such prolonged and intermittent build-outs destroy continuity, erase institutional memory, and eliminate any hope of learning-based improvements.

Finally, the criterion of dozens of reactors to benefit from learning economies and consistent improvements has not even been approached. The small number of participating European nations have each built just one or two reactors each, without sustained replication. Instead of dozens, Europe’s EPR build-out has delivered exactly two completed reactors outside of China, one each in Finland and France, both massively over budget and delayed. The United Kingdom’s ongoing struggles with Hinkley Point C and now Sizewell underscore the near-complete failure to leverage scale and experience across multiple similar projects.

Bent Flyvbjerg’s extensive research on megaprojects offers important context here. His data demonstrate consistently that nuclear projects routinely underestimate complexity, overestimate potential cost savings, and ignore historical evidence of prior overruns. Flyvbjerg’s findings indicate average overruns for nuclear reactors often range from 120 to 200% above initial estimates. Europe’s EPR experiences align closely with his analysis, underscoring that the fundamental issue is systemic rather than isolated mismanagement or technical miscalculations. The repeated pattern of underestimated costs and schedules aligns precisely with Flyvbjerg’s warnings.

Taking Sizewell C specifically, the now nearly doubled budget and uncertainty about its schedule mirror previous European EPR outcomes. Although the UK government adopted the regulated asset base model to theoretically reduce investor risk, the reality is consumers bear the brunt of these overruns, undermining the economic and political rationale for nuclear. This situation further confirms that without fundamental changes in approach, future EPR projects across Europe will likely replicate these troubling patterns.

The essential takeaway is clear. Unless European governments and industry stakeholders directly address and fulfill the criteria outlined above, nuclear power development in Europe will continue to repeat these costly cycles. Establishing clear national priorities, enforcing rigid reactor standardization, implementing centralized workforce training, committing to sustained rapid deployment, and genuinely standardizing the regulatory environment are non-negotiable if nuclear is to play a significant, reliable, and economically sensible role in Europe’s energy future.

In stark contrast to Europe’s nuclear struggles, renewable energy growth on the continent has significantly exceeded expectations during the same period. Between the mid-2000s, when the first EPR reactors entered construction, and today, Europe’s wind and solar capacity has expanded rapidly, consistently outperforming deployment targets and experiencing steady cost declines. Wind power, both onshore and offshore, has grown by more than tenfold, with major projects routinely delivered within budget and schedule.

Solar power installations have seen even more impressive expansion, driven by sharp decreases in module prices and efficient scaling of supply chains. Unlike nuclear, renewable projects benefit from short construction cycles, standardized designs, and continuous incremental improvements, underscoring Europe’s missed opportunity with nuclear and emphasizing the practical effectiveness of the renewables approach. These advantages show clearly in Flyvbjerg’s data, with wind and solar projects, along with transmission, being the three megaproject categories most likely to come in within initial budgets and schedules.

The stark doubling of Sizewell’s budget is not just a financial shock, it should be a wake-up call. The EPR reactor story in Europe does not have to remain one of perpetual disappointment, but without a realistic recognition of what successful nuclear scale requires, these overruns and delays will continue indefinitely, destroying the business cases that led to their approval in the first place. Europe must either meet these demanding but historically validated conditions for nuclear success or shift decisively toward alternatives capable of meeting its climate and energy goals without the drama and expense that have defined the European nuclear experience to date.