When Elon Musk bet that Tesla could build a 100MW battery in South Australia in 100 days back in 2017, plenty of people called it a publicity stunt. Eight years later, grid-scale batteries have become one of the most important technologies in Australia’s energy system, and the pipeline of projects under construction is massive.

Here’s where things stand.

The current fleet

Australia now has over 5GW of committed or operational grid-scale battery capacity. That’s up from essentially zero in 2017. The major operational projects include:

Hornsdale Power Reserve (SA): The original “Big Battery,” now expanded to 193.5MW/580.5MWh. It’s been wildly successful, earning its owners hundreds of millions in frequency control and energy arbitrage revenue while saving SA consumers money through reduced reliance on gas peakers.

Victorian Big Battery (VIC): 300MW/450MWh at Moorabool, near Geelong. One of the largest in the country. Had a rocky start with a fire during commissioning in 2021, but has been operating well since repairs.

Waratah Super Battery (NSW): 850MW/1,680MWh in the Hunter Valley. This is the largest battery in the southern hemisphere and one of the biggest in the world. It provides both energy shifting and system security services.

Bouldercombe Battery (QLD): 200MW/400MWh near Gladstone. Queensland’s entry into large-scale storage, providing grid stability for the central Queensland region.

Why grid-scale batteries matter for rooftop solar owners

You might think big batteries only matter for the grid, not for people with panels on their roof. But they’re deeply connected.

They reduce wholesale price spikes. Batteries charge when renewable energy is abundant (cheap) and discharge during peaks (expensive). This smooths out wholesale prices, which eventually flows through to retail rates. Less price volatility means more predictable bills.

They enable more renewable generation. Batteries address the intermittency criticism of renewables. The more storage on the grid, the higher the percentage of renewable energy that can be absorbed without stability issues. This means fewer curtailment events for rooftop solar.

They’re replacing gas peakers. Every megawatt of battery storage that displaces a gas peaker reduces the system’s dependence on expensive, carbon-intensive gas generation. This is good for the planet and good for your power bill.

The economics that changed everything

The original Hornsdale battery was partly a political statement. But it quickly became obvious that the economics were outstanding. Grid-scale batteries earn revenue from multiple sources:

• Energy arbitrage (buy low, sell high)
• Frequency Control Ancillary Services (FCAS) — keeping the grid at 50Hz
• Network support — reducing congestion on transmission lines
• Capacity payments — being available to generate during peaks

The revenue stacking makes batteries profitable in ways that surprised even their advocates. Hornsdale reportedly paid back its capital cost within the first few years of operation.

This has triggered an investment boom. The pipeline of announced battery projects in Australia exceeds 50GW — far more than will actually get built, but indicative of the confidence investors have in the technology.

What’s next

The next frontier is longer-duration storage. Current lithium-ion batteries typically store 2-4 hours of energy. That’s great for evening peaks but not for multi-day weather events where renewable generation is low for extended periods.

Technologies like compressed air, pumped hydro (Snowy 2.0, if it ever finishes), iron-air batteries, and vanadium flow batteries are being developed for 8-72 hour storage durations. Australia needs a mix of short and long-duration storage to fully replace fossil fuel generation.

Some companies are using AI consultants in Brisbane and other cities to optimise battery dispatch strategies using machine learning. The revenue maximisation algorithms for grid-scale batteries are becoming increasingly sophisticated, predicting market conditions hours or days ahead to position batteries optimally.

The political dimension

Grid-scale batteries have become surprisingly bipartisan. Even politicians who were sceptical of renewables have warmed to batteries because they address the reliability concerns about wind and solar. “What happens when the wind doesn’t blow?” is a lot less potent as a political attack when you can point to a 1,680MWh battery sitting ready to dispatch.

The CSIRO and AEMO both project that Australia needs about 60GW of storage (grid-scale plus distributed) by 2050 to support a fully renewable grid. We’re at roughly 7GW total today. The scale of investment required is enormous, but the trajectory is in the right direction.

If you care about Australia’s energy future — and if you’ve read this far, you clearly do — grid-scale batteries are one of the most encouraging developments in the sector. They work, they’re economic, and they’re being built at increasing scale. The energy transition isn’t just happening at the household level. It’s happening at grid scale too.