ACEREZ, a partnership of ACCIONA, COBRA and Endeavour Energy, is amongst the first in Australia to use next generation cloud-based grid simulation software for large scale application in the Central-West Orana Renewable Energy Zone (REZ) transmission network and the first in the country to build 16 digital substations.
The partnership was recently appointed network operator by EnergyCo for the Central-West Orana REZ, Australia’s first REZ.
In the single largest new customer order of grid simulation software for Siemens in the region, ACEREZ is using PSS®E software, part of Siemens’ Gridscale X portfolio that is used in managing 70% of the world’s electricity consumption. This software, used in over 145 countries for transmission planning, will enable faster and more scalable computing for network operators that can help save engineers up to 85% wait time in the design, operation and maintenance of the transmission network.
In addition to the grid simulation order, Siemens SIPROTEC 5, SICAM and RUGGEDCOM protection and automation technology, including digital twin capabilities, will be used in the largest venture of its kind, building 16 digital transmission substations in the Central-West Orana REZ. Compared to traditional substations, digital substations can deliver cost savings of 30–40%, significantly reduce environmental impacts, including up to a 90% reduction in copper cabling, and accelerate project timelines by as much as 50%, enhancing both infrastructure resilience and economic viability.
"ACEREZ is a showcase of leading technology and digitalization. With digital substations we have seen copper reduced by 90% and concrete reduced by 75%. With grid simulation software we can make the best decisions before we even put a shovel in the ground. Ultimately, we help avoid unintended consequences. It’s good for business and good for the environment," said Peter Halliday, Siemens Australia and New Zealand CEO.
When operational, the Central-West Orana REZ transmission project will initially unlock up to 4.5 gigawatts of network capacity, allowing generation and storage projects to connect at scale. This is expected to deliver $3 billion in net benefits for New South Wales (NSW) energy consumers, drive $20 billion in private investment to the Central-West Orana region by 2030 and bring lasting economic benefits to the area, fostering a sustainable energy future for NSW and help the state achieve its net zero targets.
Siemens technology will play a crucial role from helping simulate and analyse various aspects of the energy system – from optimising power flow to creating voltage stability, supporting grid stability and ultimately, helping speed up Australia’s energy transition.
In addition to Siemens’ technology being used, ACEREZ is also being supported by Siemens’ Power Technologies International (PTI) consultancy for energy infrastructure on the development of an automation framework to assess the compliance of new power plant PSS®E models using a digital twin of the network. PTI will help establish methodologies and requirements for conducting Small Signal Stability assessments on the new power plants.
“It’s great to see ACEREZ adopting ground-breaking technologies in their commitment to making a real difference to communities and future generations. Ultimately, people want a resilient grid delivering constant power, one that is sustainable and efficient. The pathways to this are ensuring digitalization at the heart of the grid, in the substations to increase the availability, reliability, and sustainability of the entire power supply, and staying ahead of expectations by simulating what the future could look like. The end result is an improvement in the energy transition that is better for business, society and the environment,” Mr Halliday said.

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