Nexans’ deepest HVDC subsea cable off Italy: design and integrity notes for engineers
Reviewed by Joe Ashwell

First reported on New Civil Engineer
30 Second Briefing
Nexans has installed a 500 kV high-voltage direct current subsea cable for the western section of Italy’s Tyrrhenian Link at a record depth of 2,150m in the Tyrrhenian Sea. Laying HVDC infrastructure at more than 2km water depth pushes current limits on submarine cable design, thermal performance, and mechanical protection under high hydrostatic pressure. The project signals growing demand for deepwater route engineering, advanced burial techniques, and long-term integrity monitoring for interconnector-scale power links.
Technical Brief
- Overboarding and touchdown at >2 km depth demand tight control of cable tension and bend radius.
- Record-depth HVDC work will inform design envelopes and installation procedures for future Mediterranean interconnectors.
Our Take
Among the 368 Infrastructure stories in our database, very few involve ultra‑deep subsea power assets, so Nexans’ work on the Tyrrhenian Link positions Italy as one of the more technically advanced HVDC grid-interconnection hubs in Europe.
A 500 kV HVDC rating implies a long-distance, high-capacity corridor, which in practice can help Italy integrate more remote renewable generation and reduce congestion costs on the mainland grid without adding equivalent overhead line infrastructure.
For UK-based engineering and marine contractors, the combination of a UK-headquartered publication (New Civil Engineer) covering an Italian project signals that deepwater HVDC cable installation is now seen as a specialist export opportunity rather than a purely domestic Italian capability build-out.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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