Europe’s energy transition depends on robust inspection, maintenance and repair of subsea infrastructure

Europe’s offshore energy ambitions are accelerating, with governments, utility firms, investors, and grid operators expanding offshore wind capacity at a pace that would have been difficult to imagine only a decade ago. However, alongside this desire for growth comes a less visible, but equally important, challenge: ensuring the resilience of the subsea infrastructure that supports electrification. High-voltage subsea cables now play a central role in Europe’s energy system. They connect offshore wind farms to mainland grids, strengthen interconnection between countries and help balance electricity supply across regions. As these networks grow in scale and strategic importance, maintaining their operational continuity becomes increasingly important. Subsea cables are often described as critical infrastructure, but the practical implications of that label are now becoming clearer. Unlike many terrestrial assets, offshore cable systems operate in environments that are difficult to access and complex to manage. Natural seabed movement, maritime activity, ageing infrastructure and accidental damage all create operational risks that cannot be fully eliminated through prevention alone. As a result, resilience needs to be considered alongside expansion. This is particularly relevant in Europe, where offshore wind deployment targets continue to rise. According to Nexans’ internal estimates, subsea cables installed by the company alone are expected to exceed 19,800 kilometres by 2030, with an average of around 11 repairs required annually. Failures are not exceptional events in long-term offshore operations. They are part of the operational reality of large-scale infrastructure systems. The key question is therefore not whether repairs will be needed, but how quickly and effectively systems can recover when disruption occurs. This is where inspection, maintenance and repair (IMR) strategies become increasingly important. IMR must be prioritised as a strategic objective Historically, IMR has often been viewed as a specialist operational function rather than a strategic pillar of energy infrastructure planning. That perspective is changing. Across the offshore energy sector, operators are recognising that preparedness can significantly reduce downtime, minimise economic disruption and improve confidence in long-term infrastructure investment. An effective IMR strategy combines several capabilities. Inspection services help identify vulnerabilities and assess risk exposure across cable routes. Maintenance programmes support long-term asset performance through testing and readiness checks. Repair capabilities ensure that vessels, spare cable sections, equipment and specialist teams can be mobilised efficiently when required. The challenge for Europe is that these capabilities cannot be developed overnight. The sector currently faces a combination of constraints, including limited vessel availability, shortages in specialist engineering skills, fragmented permitting processes and the absence of coordinated frameworks for strategic repair readiness. Industry organisations including the European Subsea Cables Association (ESCA) and the International Marine Contractors Association (IMCA) have already highlighted these issues in discussions surrounding the European Union’s Action Plan on Cable Security. The EU’s growing focus on subsea infrastructure resilience is therefore a positive development. Recent initiatives aimed at strengthening prevention, detection, response and recovery capabilities reflect a broader understanding that energy sovereignty also depends on operational continuity. Collaboration has begun in earnest Simultaneously, resilience requires close cooperation between industry and public authorities. Offshore cable repair operations involve specialised assets, long planning horizons and highly technical expertise. Accelerating emergency permitting, supporting workforce development, and improving coordination around spare equipment and vessel readiness could all strengthen Europe’s ability to respond effectively to future outages. There are already prevalent examples of how preparation and collaboration can improve outcomes. Following the failure of the Estlink 2 interconnector between Finland and Estonia in December 2024, rapid mobilisation efforts enabled repair operations to begin quickly. Engineering teams, repair equipment, and offshore vessel resources were coordinated to replace a damaged cable section and restore the connection on schedule. Projects like this demonstrate the value of having proven repair frameworks and experienced technical teams already in place before incidents occur. Looking ahead Resilience is likely to become a more visible part of infrastructure investment decisions. Investors, utilities, and policymakers increasingly want assurance that offshore assets can maintain continuity over their full lifecycle, not only during installation, but throughout decades of operation. This broader shift reflects the growing maturity of Europe’s offshore energy market. The conversation is no longer limited to how quickly new infrastructure can be deployed. It also includes how effectively that infrastructure can be protected, maintained, and restored over time. For those of us with responsibility over subsea cables, this represents an opportunity to rethink resilience as an integrated part of energy strategy rather than a reactive operational requirement. IMR capabilities may not attract the same visibility as new generation capacity, but they remain fundamental to the reliability of the wider system. While Europe’s electrification journey will depend on building new infrastructure, it is also imperative that critical networks remain reliable in an increasingly complex operating environment. By Nexans senior executive vice president for power transmission Pascal Radue. Like what you've read? To receive New Civil Engineer's daily and weekly newsletters click here. Have your say or a new account to join the discussion.