Maintaining a reliable electricity supply to the NSW North West Slopes

Transgrid forecasts indicate electricity demand in the North West Slopes is expected to increase substantially due to a number of significant industrial loads anticipated to connect as well as general load growth in Narrabri and Gunnedah.

If the longer-term constraints on load growth aren’t resolved it could result in the interruption of a significant amount of electricity supply

Transgrid has been reviewing options to avoid interruption to customers and has published the Project Assessment Conclusions Report (PACR) into securing the region’s power supply into the future.

Executive General Manager of Network Marie Jordan says it is a significant milestone.

“We looked at multiple options for addressing load constraints on our network and we are excited to say that grid-scale batteries have been identified as the preferred option as they provided the greatest overall benefit.

“This project is amongst the first in the National Electricity Market where a solution involving a large-scale battery has outperformed other options throughout the regulatory test.

“It is another sign of how rapidly our energy system is changing and how we need to adapt and embrace new technology as we embark on the energy transition. Transgrid actively seeks out opportunities to partner with non-network providers to deliver innovative solutions where they are better for customers than traditional network infrastructure alone,” she said.

Two proposals from separate third parties for a grid-scale Battery Energy Storage System (BESS) were ranked equal in the PACR assessment.

The two BESS options were found to deliver approximately $513 million and $496 million in net benefits respectively.

The non-network solutions will provide up to 57 MW and 20 MVAr in the Gunnedah area, providing both network and dynamic reactive support by 2030 to manage thermal constraints and voltage variations during high demand periods.

The BESS options were generally found to have higher benefits because they can be commissioned sooner than the network only options, avoiding the risk of supply outages in the short-term.

The preferred option also includes upgrades to the local transmission network:

• A non-network BESS at Gunnedah substation
• The installation of a third 60 MVA 132/66 kV transformer at Narrabri substation
• Rebuilding the existing transmission line between Tamworth and Gunnedah substations as a double circuit line (longer term)
• Upgrading the line between Narrabri and Boggabri North to a higher rating (longer term)

All transmission line upgrades would use existing routes so we can minimise disruption to the community.

Subject to all relevant approvals, the battery at Gunnedah could be in operation by 2024-2025.

Transgrid will now enter a competitive procurement process and begin commercial negotiations with non-network proponents to put a contract in place.

You can also read more about the North West Slopes Area supply project here.