Transend - Appendix 5 Renewal capital expenditure - Australian ...

7.6.3 DRAWBACKS
The drawbacks for this option are that:
0BInvestment Evaluation Summary
TNM-GS-809-0720
� it may require longer outages for implementation, depending on the implementation methodology adopted; and
� technology risk as Transend has not previously utilised hybrid switchgear in its transmission network.
7.6.4 CONCLUSION
This option is technically viable.
8 OPTION ESTIMATES
A comparison of the net present value of options is provided in Table 1.
Table 1 – Comparison of options considered
Option Net present value of costs ($M June 2007)
1 Manage existing assets and defer replacement -12.71
2 Replace assets in-situ -13.63
3 Staged replacement of selected assets in-situ -13.16
4 Redevelop using air insulated switchgear -13.07
5 Redevelop using gas insulated switchgear -12.68
6 Redevelop using hybrid switchgear -12.67
The economic analysis includes the cost impact to customers in the event of a major circuit breaker failure using a
probabilistic approach based on current and forecast load data for each individual transmission circuit connected to
Creek Road Substation.
9 PREFERRED OPTION
Given the constraints and numerous construction methodologies that may be implemented, options 3, 4, 5 and 6 are
acceptable options.
Transend intends to issue this project as a design and construct package to achieve the best economic outcome. The
project documentation will leave it open to tenderers to submit arrangements that may include AIS, GIS or hybrid
switchgear solutions. Transend completed a very similar redevelopment project at Risdon Substation. This project was
competitively sourced using a ‘design and construct’ contracting framework. The least-cost solution proposed by
tenderers was the application of GIS technology.
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