PART 1: Cable Integrity in Offshore Wind - The Real Risk is What You Can’t See
- The Impulse Group
- 2 days ago
- 4 min read
Offshore wind has not created a new class of subsea risk. It has exposed an old one.
Across subsea systems, a familiar pattern continues to emerge. Assets rarely fail because engineers misunderstood the fundamentals, more often they fail because real operating behaviour gradually drifts away from design assumptions, and the change goes unnoticed until it is too late.
From our perspective, the cable failures emerging across offshore wind feel uncomfortably familiar. At The Impulse Group, we recognise these patterns because we have seen them before – in subsea risers, foundations and interface systems across decades of offshore engineering.
Different assets, but the same underlying story.
Where Operators Are Still Being Surprised
Subsea foundations, inter-array cables and scour protection systems operate in aggressive, dynamic marine environments. They are continuously exposed to changing seabed conditions, metocean loading and installation realities that no model can ever fully replicate.
The most critical moment often comes earlier than expected.
At the moment a cable leaves the laying vessel and meets the seabed, it can experience over-bending, tension loading and interface geometries that differ significantly from the original design intent. Lead-ins to monopiles, crossings, touchdown zones and transitions quickly become high-stress areas.
What follows is rarely a sudden failure. Instead, damage accumulates quietly and gradually through fatigue, cyclic strain and repeated loading.
This pattern is not new – in deepwater riser systems, investigations repeatedly showed that actual field behaviour was more severe than design assumptions predicted, particularly at interface zones such as bend stiffeners and top sections.
One well-documented deepwater riser failure investigation concluded:
“The consensus was that the failure was due to fatigue, progressive crack growth, caused by unrecognised operating loads.”
The failure itself was not unexpected – the warning signs were simply not visible early enough.
The Limits of Survey Only Thinking
In offshore wind, subsea cables are still largely managed through periodic inspection.
Typically, this involves ROV or sonar surveys, sometimes supported by electrical testing once performance degradation has already begun. These surveys provide valuable information, but they are expensive, weather-dependent and provide only a single snapshot in time.
If a cable becomes exposed following a storm, develops a free span or starts accumulating fatigue damage at an interface, that change may remain undetected for months. By the time it is observed, the damage is already embedded.
As one cable monitoring specialist puts it:
“Sudden and catastrophic failure in subsea power cables is most frequently the consequence of a lack of consistent and comprehensive data on mechanical endurance.”
This is not a criticism of inspection, it is a recognition of its limits. Inspection shows what the cable looked like at a moment in time. It does not show what the cable is doing.
The Risks You Cannot See Without Continuous Insight
Failure trend data consistently shows that the largest contributors to cable failure originate from installation effects, manufacturing variability and interface behaviour. These issues rarely present as immediate faults; they develop gradually as fatigue and strain problems in very specific zones.
· Touchdown areas
· Crossings
· Structural interfaces
· Zones of insufficient burial or evolving seabed conditions
These are precisely the areas where static inspection provides limited foresight, and where continuous insight adds the most value.
The same lesson was learned the hard way in riser systems. Flexible risers are vulnerable to dynamic loads, with fatigue driven by wave action, vortex induced vibration and platform motion. Studies repeatedly showed fatigue damage concentrating at upper and lower sections, often driven by operating loads that were never fully recognised during design.
In both cables and risers, operators are surprised for the same reason – the behaviour that mattered most was never continuously measured.
Why Service Matters More Than Sensors
One of the clearest lessons from subsea riser integrity management is that the real value never resided in the sensor itself, it sat in the engineering service around it:
· Design challenge and understanding
· Installation oversight
· Data interpretation
· Clear, actionable recommendations and decision support
Modern cable monitoring providers are increasingly adopting this same philosophy. The focus is not simply on measuring temperature, strain or acoustic signals, but on turning those signals into meaningful insight that reduces uncertainty and guides intervention.
In other words, the value is not the data, the value lies in what you do with it.
This is how riser integrity has been successfully managed for years: not as a technology exercise, but as an engineering-led service that supports decision-making across the asset lifecycle. The same model is now emerging for cables.
Inspection vs Visibility
Put simply, inspection is like an annual MOT. Visibility is having a live dashboard and warning lights every time you drive. Both have value, but only one tells you when something is changing in real time.
The Real Shift the Industry Is Facing
The offshore wind industry does not lack technology, it lacks continuous confidence.
As projects scale, water depths increase and interfaces multiply, managing cables through episodic inspection alone becomes an increasingly high-risk strategy. The shift now underway is not about adding more systems, but about adopting the same integrity mindset that subsea engineering has already learned through experience.
Understand behaviour, track change and act before failure, because this is not fundamentally a cable problem; it is a visibility problem.
From Visibility to Confident Decisions
At The Impulse Group, we help operators move beyond snapshots and into true asset understanding. By combining continuous insight with decades of subsea integrity expertise, we turn data into clear, practical decisions that protect safety, performance and long-term asset value.
Whether supporting offshore cables, risers or complex interface systems, our focus remains the same: give operators the confidence to act early, not react late.
If you are reassessing cable integrity, managing ageing assets, or seeking clearer insight into real operating behaviour, our engineering team is ready to support you.
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