Marine inspection surveys: a way to safeguard subsea power cables

Subsea power cables can be impacted by external forces, such as fishing activities, anchoring, waves and currents, but also by malicious activities. Following several incidents with damaged infrastructure in recent years, submarine power cables and their significance to the security of supply have gained attention, highlighting the potential consequences of neglecting cable maintenance.

Cable incidents result in operational disruptions and safety risks, and they typically incur substantial costs for their operators. However, hidden beneath the surface and mostly out of sight, preventive monitoring and maintenance can be intricate and complex.

So, how can offshore cable operators proactively achieve long-term cable health and operational efficiency? One way is by conducting periodic marine inspection surveys mapping among other things how deep the cable is buried or whether it is spanning freely over the seabed, or if there are large rocks that may damage the cable. Also, data from past marine surveys can be compared to the current information to identify possible risk areas.

Subsea cables are exposed to different kinds of surfaces or subsurface anomalies, such as damaging structures or objects lying in their vicinity. Also, there is a risk of incidents from cables being exposed on the seabed or not lying deep enough.

To safeguard offshore wind electricity production and interconnectors, power outages must be prevented. Improved cable designs, manufacturing, and installation can only form part of the solution. The other part of the equation is continuous asset monitoring, paired with proactive risk mitigation activities, such as marine inspection surveys, which provide additional operational insights.

To improve a cable's availability, it is important to keep track of its latest physical condition, investigate associated risks, and mitigate them well in advance – before they potentially materialise into an unexpected breakdown.

To efficiently utilise offshore power cable systems, it is critical to safeguard and enable their infrastructure. Preventive maintenance and marine inspection surveys play a role in maintaining high-performing cable connections essential to the transition to renewable energy.