PART 2: The Real Cost of Offshore Wind Cable Failure Isn’t the Cable – It’s the Downtime

In offshore wind, subsea cables account for a relatively small proportion of total project capital cost, yet they account for a disproportionate share of financial loss. That contradiction sits at the heart of why cable integrity has become such a persistent concern for operators, insurers and investors alike.

The challenge is not that cables fail frequently, it is that when they do, the consequences escalate quickly – operationally, financially and strategically.

Where the Money Is Really Lost

Across multiple independent datasets, the conclusion is consistent.

DNV, drawing on Lloyd Warwick loss-adjuster data, reports that approximately 83% of offshore wind insurance claims and associated financial losses are attributed to power cable failures.

The average downtime typically reaches:

• 40 days for inter-array cable repairs

• 60 days for export cable repairs

When both repair cost and lost generation are combined, typical financial losses fall in the range of:

• $1.2m to $12m for inter-array cables

• $10m to $30m for export cables

Strathclyde University and IMCA report closely aligned findings.[1] Crucially, DNV also notes that vessel charges frequently dominate claims costs, far outweighing the value of the physical cable being replaced.

In practical terms, the largest financial driver is not the asset, it is the interruption, in downtime and vessels.

A Familiar Pattern From Subsea Engineering

This dynamic is not unique to offshore wind. In flexible riser systems, the true cost of failures have long been understood to lie in lost production rather than in hardware replacement.

When fatigue damage or suppression-device issues emerge after installation, the consequences often extend far beyond repair to include re-evaluation, re-design, potential replacement and extended production deferment.

Deepwater riser failure investigations consistently identify installation loads, unrecognised operating conditions and interface behaviour as key contributors, with operational impact outweighing physical repair costs.

Different assets. Same economics.

Why Commercial Conversations Lag Technical Reality

Technically, the offshore wind sector already understands where the risk resides. DNV, GCube and others have repeatedly identified subsea cables as the most frequent and expensive loss category in offshore wind. GCube’s analysis shows cables are responsible for over half of total claims spend, despite representing a fraction of project capital expenditure.

Yet, commercial structures, standards and insurance terms are still catching up.

GCube’s Uncharted Waters report describes how market losses grew sharply between 2010 and 2020, with average claim values nearly doubling. The report explicitly calls for stronger design standards, improved interface management and clearer risk allocation to align commercial frameworks to operational realities. [2]

DNV similarly highlights the need for stronger project-level requirements and improved interface management through standards such as DNV-ST-0359.

In other words, the evidence is already there, but the contracts and frameworks are lagging behind.

The offshore wind sector is not unusual in this respect. Flexible risers went through the same cycle – early qualification could not fully anticipate the range of fatigue and interface failures that emerged in service. Design codes, inspection regimes and commercial expectations evolved only after costly lessons were learned.

Engineering reality usually moves first and commercial alignment follows.

What Actually Makes Insurers Nervous

From an insurance perspective, concern does not stem from asset complexity alone, but from how multiple risk factors combine.

• Multiple interfaces and transitions

• High sensitivity to installation quality

• Strong dependence on site-specific conditions

• Long outages when things go wrong

• Large, correlated losses driven by vessels and downtime

DNV points to poor interface design management and insufficient consideration of actual site conditions as root causes in many recent failures. GCube highlights contractor error during transit and installation as dominant contributors to both claim frequency and severity.

These themes mirror those long observed in riser integrity investigations:  unrecognised loads, interface complexity and installation effects that were not adequately addressed during design.

What worries insurers is not sophistication, it is uncertainty at interfaces, under real operating conditions, where financial consequences are high.

Reducing Exposure Means Minimising Surprises

The most effective way to reduce insurance exposure is not to promise zero failures - an unrealistic goal in complex offshore systems – but to minimise surprises via:

• Earlier insight into changing behaviour

• Clearer understanding of where risk is accumulating

• Evidence-based decisions on when and where to intervene

This is why the conversation increasingly shifts away from stand-alone inspection and towards how data, engineering insight and disciplined integrity management should be used together.

Data alone does not reduce premiums, confidence does.

Why Service Matters More Than Tools

Our experience has shown that measurements without interpretation and expert insights carry limited value. What really matters is the ability to demonstrate structured, evidence-based integrity management and an appetite to strive for continuous improvement. Always ask:

• Is behaviour changing?

• Are loads higher than expected?

• Are interfaces behaving as designed?

When those questions can be answered clearly, risk becomes quantifiable rather than speculative.

This is not new thinking. It is the same service-led integrity model that evolved around flexible risers and other critical subsea systems over time. Monitoring, analysis and verification were not adopted as technology exercises, but as ways to limit the unknowns that drive financial loss.

The offshore wind cable sector is now moving along the same path – not because of technology, but because of the exposure of financial realities.

The Direction of Travel Is Clear

As offshore wind assets scale and financial stakes increase, cable integrity will increasingly be judged through an insurance and investment lens, not just an engineering one.

Operators who can demonstrate visibility, understanding and informed decision-making will find risk easier to predict and manage. Those without this clarity will continue to face rising premiums, tighter conditions and increased financial exposure.

This is not about monitoring for the sake of it, it’s about managing downtime – and that is where the real cost has always been.

Acting Earlier to Protect Performance

At The Impulse Group, we believe integrity is not about reacting to failure – it is about understanding behaviour early enough to stay ahead of it.

By combining real-world offshore engineering experience with data-driven insight, we help operators turn uncertainty into clear, confident decisions that maintain operations, reduce financial exposure and extend asset performance.

If cable reliability, downtime risk or long-term asset confidence are part of your challenge, our team is ready to support you.

Learn more at www.theimpulsegroup.com or speak directly with our engineering specialists to explore how greater visibility can translate into stronger performance.

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[1] The University of Strathclyde ran an EPSRC‑funded project titled “Reliability‑Cost Analysis of Subsea Transmission Cables” (PI: T. Bedford, 2017–2020), which focuses on reliability and cost modelling of subsea transmission cables.

[2] According to a report by GCube Insurance in 2021, the average insurance claim nearly doubled from £1.7 million (€2 million) in 2010-2015 to £3.1 million (€3.6 million) in 2020. In total, claims for offshore wind grew from around £124 million (€145 million) in 2010-2015 to around £500 million (€585 million) in 2020. Of these, around 50% were down to damage to subsea cables, with other insurers estimating that damaged subsea cables represent between 70% and 80% of their claims.