Dutch survey specialist Deep has secured a multi-year contract from TenneT covering annual integrity surveys across the transmission operator's offshore cable infrastructure.

The Amsterdam-based company will carry out the campaigns annually between 2026 and 2029. The work will rely on hydrographic and geophysical surveys to measure cable burial depth and identify seabed features or objects that could pose a threat to cable integrity. Where required, selected findings will also be followed up with visual inspections.

Cable burial depth monitoring is a core part of offshore grid maintenance, as seabed conditions can change over time through natural processes such as sand waves and scour, potentially leaving sections of cable less deeply buried than originally installed. Regular integrity surveys allow operators to identify such exposure before it becomes a risk.

TenneT, the Dutch and German transmission system operator, is responsible for connecting offshore wind farms in the North Sea to the onshore grid and is expanding its offshore grid under the Netherlands' rollout of large-scale offshore wind capacity, making systematic monitoring of an expanding cable network an ongoing requirement.

The survey results will feed into TenneT's maintenance and integrity management programme, as the Dutch transmission operator continues to expand its North Sea offshore grid.

No contract value was disclosed.

Deep specialises in hydrographic, geophysical and UXO surveys, and operates its own fleet of crewed and uncrewed survey vessels.