Spencer Gulf Emergency Bypass

The customer

As the principal owner and manager of South Australia’s high-voltage transmission network, ElectraNet plays a critical role in driving the state’s global leadership in the clean energy transition. The company is actively building the “electricity superhighway” required to support South Australia’s target of reaching 100% net renewable energy by 2027. Through major infrastructure expansions and a commitment to achieving net-zero operational emissions by 2040, ElectraNet is ensuring the grid remains affordable, secure, and capable of unlocking massive economic and industrial growth.

The Eyre Peninsula relies entirely on the radial Davenport-to-Cultana 275 kV double-circuit overhead transmission line. A critical 1.5-kilometer stretch of this line crosses over the waters of the Spencer Gulf.

With their joint focus on supplying consistent access to power for the community, Enerven were appointed to parter with ElectraNet in the design and construction of a bypass.

The opportunity

The key driver for this project is to mitigate consequences for prolonged disruption of supply to Eyre Peninsula should structure failure of the gulf crossing occur due to extreme wind events or other, by preparing alternative transmission lines for emergency deployment. It was proposed that both northern and southern bypass options are made ready to provide a credible bypass solution, enhancing preparedness for community power access.  This also provides an opportunity to reinstate the second 275 kV circuit in a timely manner.

The solution

Key specifications delivered by Enerven:

• Structure uprating from 132 kV structure and insulator arrangement to 275 kV structure and insulator arrangement
• Re-insulating and re-conductoring existing structures to ensure both bypasses are suitable for 275 kV
• Increasing the wind rating of F1808 and F1809 so that at least one bypass is likely to withstand a high wind event. Part of this solution was removing 30m and 20m sections of two different towers in the Spencer Gulf. Two 10m sections were rebuilt and flown back on each of the towers.

Reflections from Kurt Mirus, Enerven Manager of Transmission Lines Construction

The Enerven team demonstrated exceptional performance and technical expertise on the Spencer Gulf project. Enerven’s established capability in complex conductor stringing was fully demonstrated, further enhanced by our successful integration of internal drone operations.

A massive commendation goes to the entire team for seamlessly and safely coordinating a highly complex, multi-modal interface. Managing the simultaneous deployment of watercraft, barges, heavy-lift helicopters, and specialised drone technology over a marine environment—all while maintaining zero-harm safety standards—is a testament to the team’s operational discipline and execution efficiency.