Key takeaway: The model solves a transmission network with over 200 nodes, representing individual transmission lines and substations rather than broad regional zones. The network grows over the forecast horizon in line with AEMO's transmission development pathway.
The transmission network is built from Geoscience Australia’s transmission topology, giving each modelled line its own voltage, length, thermal rating, and electrical characteristics. Generators and loads are mapped to the specific network node closest to their physical location, so the model can capture how power actually flows between generation, demand centres, and interconnectors.
The network is built up in layers, from base topology to committed and planned upgrades
The base network reflects transmission assets as they exist today. On top of this, the model applies a set of network augmentations that bring the topology forward to each forecast year:
- Named projects: committed and anticipated transmission upgrades from AEMO’s Integrated System Plan (ISP), including HumeLink, VNI West (Victoria–New South Wales Interconnector West), Project EnergyConnect, Project Marinus, and Queensland–New South Wales Interconnector (QNI) Connect, along with Renewable Energy Zone (REZ) network augmentations. Each project is added from its AEMO-committed capacity release date.
- Smaller ISP projects: upgrades too granular to model as a single new line are distributed across the existing backbone lines in the affected area, weighted by their current capacity.
This means the network’s transfer capability grows over the forecast horizon in line with AEMO’s actual transmission development pathway, rather than being held fixed at today’s rated capacity.
Renewable Energy Zones are mapped to the nodes where new capacity can connect
Each Renewable Energy Zone (REZ) is mapped to the specific transmission nodes within it that are eligible to host new generation and storage. When the model’s capacity expansion process builds new wind, solar, or battery capacity, that capacity is only permitted to connect at REZ-eligible nodes, reflecting the physical constraint that new renewable build is concentrated where REZ network access exists.
How this network translates into a distinct price at every node is covered on the Nodal Pricing page.