T&I · Submarine Cable · Offshore Wind

TPC II

End-to-End T&I Delivery — Concept to Offshore Execution

Year 2025 Region Taiwan · Changhua Phase 2 Programme 8-Month Concept-to-Install

Concept to ready-to-install in 8 months — engineering, mobilisation strategy, vessel chartering (CLV, CLB & support), MWS approvals, pull-in systems and a redesigned CPS for scour mitigation. A scope that normally runs 2 years, delivered for the entire submarine cable installation programme on TPC II.

The Challenge

2-Year Programme. 8 Months on the Clock.

Develop the entire operation strategy for the TPC II submarine cable installation — from concept to ready-to-install — in 8 months. That meant owning mobilisation, chartering of the CLV, CLB and support vessels, the full MWS approval chain, designing the pull-in systems, and redesigning the CPS for scour mitigation. Programmes of this scope normally run two years end-to-end.

01Strategy in 8 MonthsConcept through ready-to-install for the full T&I programme — a 2-year scope compressed into eight months.
02Vessel CharteringCLV, CLB and support-vessel chartering, mobilisation and integration sequenced inside the same window.
03MWS & Pull-In SystemsFull MWS approval cycle and engineered shore / TJB / OSS / FOU pull-in systems to operation-ready.
04CPS RedesignCable Protection System redesigned for scour mitigation — engineered, validated, and approved on schedule.

Overview

TPC II

Awarded as the engineering and offshore-execution partner for the TPC II (Taiwan Power Company / Changhua Phase 2 — 300 MW) programme, Dimension delivered the full T&I scope from concept through offshore execution — from cable, vessel & subsea engineering to PLGR, seabed levelling, TJB pull-in, OSS & FOU pull-ins, CLV operations, cable burial, tower transfers and post-lay support.

The work integrates cable laying, equipment supply & mobilisation, CPS stabilisation & scour protection, crossings, walk-to-work solutions, vessel mobilisation, cable repair and full T&T support under a single delivery framework.

Scope of Work

What Dimension Delivered

01Cable, vessel & subsea engineering — end-to-end FEED through detailed design
02Shore / HDD pull-in — long intertidal & alter-course pull-ins, beach roller solutions, intermediate barge engineering
03TJB pull-in — layouts, winches, sheaves, rollers, HDD seal installation, pull-in crew & equipment operators
04OSS pull-in — pull-in layouts, equipment mobilisation, cable J-tube hang-offs, walk-to-work crew transfer
05CLV operations — layout, equipment mobilisation, 1st & 2nd-end pull-ins, CPS & pull-in head assembly, trencher and ROV ops, DP assessments
06FOU pull-in — foundation pull-in layouts, J-tube hang-offs, FOU crew & equipment transfer
07Cable burial — trenching support vessel layout, CBRA, BAS, post-lay & simul-lay-and-bury, jetting sleds, ROV trenchers, vertical injectors
08Tower transfer — walk-to-work, tower lifting, SOVs, emergency response and evacuation procedures
09Seabed preparation — mass-flow excavation, seabed ploughing, jetting solutions, PLGR debris clearance, dredging volume assessments
10Scour assessments & CPS stabilisation — rock bags, mattresses, rock berms, CPS interface engineering
11Subsea survey — geotechnical review, metocean, sub-bottom profiler, magnetometer, side-scan sonar, MBES, touchdown monitoring, ROV-based monitoring, as-trenched survey
12Cable crossings — mattress / bridge, rock-bag, scour and stability assessments, ROV release deployment frame
13Cable repair — in-line repair with omega loops, vessel deck arrangement, joint over-boarding and subsea protection

Parameter	Value
Export Cable Voltage	161 kV
Export Cable Diameter	280 mm
Export Cable Length	22 km per cable
Number of Lines	3
Total Cable Weight	≈ 8,700 tonnes
Wind-Farm Output	300 MW (Changhua Phase 2)

Highlights

What Made It Notable

— 01
Single point of accountability across 13 T&I workstreams from cable engineering through cable repair.
— 02
SFE Adventurer cable-lay package delivered by Dimension — carousel, tensioner, quadrant, chute, A-frame, trencher integration.
— 03
Burial Assessment Study (BAS) + post-lay burial + simul-lay-and-bury executed across 3 export cables.
— 04
Subsea survey suite — sub-bottom profiler, magnetometer, side-scan sonar, MBES, touchdown monitoring and as-trenched.