SP Renewables 1.8km HDD subsea ducts: design and stability notes for engineers
Reviewed by Tom Sullivan
First reported on New Civil Engineer
30 Second Briefing
ScottishPower Renewables has installed two 1.8km-long, 800mm-diameter subsea cable ducts from the Suffolk coast towards its East Anglia TWO offshore wind farm using horizontal directional drilling, which it describes as a global engineering first. The HDD drive length and pipe diameter push current limits for marine landfall works, reducing the need for open-cut trenching through the intertidal zone. For civil and geotechnical teams, the project signals growing demand for long-reach HDD design, precise bore path control and robust annulus stability in weak offshore sediments.
Technical Brief
- HDD landfall works are being delivered for ScottishPower Renewables’ East Anglia TWO offshore windfarm export route.
- Similar long-reach HDD landfalls are likely to become standard for UK offshore wind export cables.
Our Take
The East Anglia TWO offshore windfarm already features in our database via Smulders’ contract to equip 64 turbines with Palfinger davit cranes, signalling that ScottishPower Renewables is locking in specialist contractors across both foundation and cable-landfall scopes at an early stage.
Using horizontal directional drilling for 800 mm, 1.8 km subsea ducts at the Suffolk landfall reduces open-cut disturbance on a sensitive coastline, which aligns with the ‘Sustainability’ tag pattern in our Infrastructure coverage where HDD is increasingly preferred for grid connections in constrained coastal zones.
ScottishPower Renewables’ separate five-year O&M deal with Natural Power on Scottish onshore sites suggests the operator is building a long-term stable of service partners, which could streamline future operations once East Anglia TWO transitions from construction to O&M.
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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