Securing the grid for a renewable future

As Australia moves to a renewable electricity supply, the foundations of power system security are being challenged and transformed.

Coal-fired generators are retiring, new technologies are scaling rapidly, and decades-old rules and assumptions are being tested in real time.

The Securing Power Systems in the Renewable Revolution White Paper, released early February by the NSW Decarbonisation Innovation Hub’s Electrification and Energy Systems Network, UNSW Energy Institute and the University of Wollongong, offers a clear-eyed view of what this transition means for grid security.

Drawing on insights from industry, academia and government, it identifies the key issues for maintaining reliable, cost-effective energy in a high-renewables system.

From spinning machines to software

The power system has historically relied on large spinning generators in coal-fired power stations to maintain grid stability, respond to faults and ensure equipment works together. As generators are retired, these functions can no longer be taken for granted.

“We’re moving from a system governed by physical properties to one controlled by software and power electronics,” said UNSW Professor and AGL non-executive director Mark Twidell, a White Paper co-author. “That’s effectively an analogue-to-digital transformation of the network.”

The system increasingly relies on inverters to convert renewable energy into grid-ready power. They are fast and flexible, but respond differently from traditional generators during disruptions.

“The main risk isn’t normal day-to-day operation,” Mark said. “It’s how inverters respond during faults and disturbances, and whether existing protection systems can continue to operate reliably when those responses change.

“The White Paper calls for closer industry collaboration to harness existing data to understand inverter behaviour and plan ahead.”

Dealing with uncertainty

Australia’s energy transition is not a leap into the dark. Renewable penetration has already reached 70-80% at times, without compromising system security.

But operating a highly renewable grid at scale, across seasons and under extreme conditions introduces new uncertainties.

“This hasn’t been done before on grids of this size, and some core protection mechanisms may not function the way we assume,” Mark said. “There are also unknown unknowns, particularly around large, unexpected events like faults, storms or major network disruptions.”

To address this, the paper calls for greater investment in testing, validation and simulation, including digital twins and real-time simulation environments that allow future systems to be built and tested virtually before deployment.

“No pilot flies a new aircraft without thousands of hours in a simulator,” he said. “Power systems need the same level of rigour, so we have confidence in how new technologies will behave together before they are rolled out at scale.”

The heartbeat of the grid

The White Paper questions assumptions about managing the grid as distributed energy resources expand. Australia now has more than 4.3 million rooftop solar connections, alongside a rapidly growing battery ecosystem.

“At some point we have to ask whether we’re still connecting new things to a legacy grid, or whether the new things are the grid,” said co-author Ty Christopher, Director of the Energy Futures Network at the University of Wollongong.

A key concern is maintaining the grid’s “heartbeat” – the steady frequency that keeps electricity stable – without traditional generators.

One solution is synchronous condensers, or syncons: large spinning machines that provide inertia to dampen fluctuations and power surges, enabling safety systems to operate. But they are costly, slow to install and globally scarce.

The paper explores whether distributed, inverter-based resources could play a greater role in network stability, using newer grid-forming inverters that actively regulate voltage and frequency during disruptions.

“Inverters can respond in fractions of a second and could play a similar role to syncons in stabilising the grid, but this hasn’t been proven at scale,” Ty explained.

“Ultimately, grid stability is unlikely to come from inverters or syncons alone. The most likely outcome is a mix of technologies. The question is: what is the right mix?”

The paper also examines whether existing rules and standards are fit for purpose to support that technology mix.

“We’re trying to manage a 21st-century grid with 20th-century regulation,” he said. “Those rules were written for a system that simply no longer exists.”

Pathways forward

The White Paper sets out a national approach to electrification built on partnerships between industry, academia and government. It seeks to address the immediate, high-stakes challenges, while also establishing a framework to resolve longer-term strategic issues that affect a wide range of stakeholders.

Its ultimate purpose is to provide a shared evidence base and clear priorities for those shaping the energy transformation.

“This is about laying out the questions and the research pathways needed to answer them,” Mark said. “It’s about helping stakeholders move from uncertainty to informed action.”

Ty describes the paper as an invitation to regulators and policymakers to engage with independent, academically rigorous analysis as the pace of change accelerates.

“Not making a decision is still making a decision,” he said. “The goal is to support reform that maximises long-term benefits for energy consumers, while keeping the system safe, secure and reliable.”

The White Paper aims to help the sector navigate one of the most critical technical, policy and economic challenges of the energy transition: keeping the lights on while transforming the grid for a fully renewable future.

We thank the White Paper authors: Mark Twidell, John Fletcher, Georgios Konstantinou, Felipe Arraño-Vargas, Ty Christopher, Mark Lewis and Dani Alexander, and reviewers: Shan Jiang, Gregor Verbic, Jin Ma, David Hill, Neville Henderson and Stefan Trueck, for their invaluable input.