Construction Type / Project Phase
Procurement Fabrication
Offshore Installation
MC + 2 % + 32 %
HUC
Net Total Savings
IC + 11 % + 68 % + 15 %
Figure 6: Cost Estimation Comparison
Based on similar rates for unit steel and labour, material costs for the IC method is slightly higher mainly due to additional steel requirement for LSF however, the fabrication cost for MC are higher due to additional work on steel interfacing and MSF. Furthermore, the installation cost for IC far exceeds that for MC due to more stringent barge requirement to cater for the float-over installation method for IC. In terms of offshore installation duration, the IC still took less days compared with MC. In addition, the HUC cost for IC resulted in significant cost saving of more than 60 % compared with that of MC due to less offshore HUC requirement. All the above indicates that overall, the IC method offers significant cost saving compared with MC.
Conclusion
Both integrated and modular concepts have their merits. While the IC provides opportunity for an accelerated first production date and overall cheaper project cost, it suffers from higher upfront investment, heavier FEL activities and lower design flexibility, as the installation vessel needs to be locked-in upfront. The modular concept provides the flexibility, with wider selection of fabricators and installation vessels.
Eventually, it is up to the project owner to weigh the pros and cons of both options, to suit the needs of the project.
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