Batteries Power 37% of Western Australia's Peak Demand

On May 9th, battery storage systems across Western Australia did something remarkable: they powered 37.2% of the state's peak electricity demand, marking one of the highest battery penetration levels ever recorded in an isolated grid anywhere on Earth.

The record came on a Saturday evening after a sunny day when renewable energy supplied 78% of the state's power generation. For the entire weekend, renewables provided more than half of Western Australia's electricity needs.

These numbers come from the South West Interconnected System, Western Australia's main power grid that operates completely independently from the rest of Australia. The grid covers an area larger than many European countries and serves the state's 2.8 million residents.

What makes this achievement even more impressive is how quickly it happened. Western Australia's battery capacity has exploded over just the past two years, driven by some of the largest battery installations in Australia.

The biggest system is a massive 2,400MWh battery in Collie, owned by energy company Synergy. Right next to it sits another giant 2,200MWh battery owned by renewable energy company Neoen. Collie isn't randomly chosen—it's the heart of Western Australia's coal country, where aging coal plants are scheduled to close by 2030.

The Ripple Effect

Western Australia's battery boom isn't happening by accident. Federal and state governments created funding programs specifically designed to replace coal with clean energy storage as old plants retire.

Under the Capacity Investment Scheme, the government has funded battery projects totaling over 6 gigawatt-hours of storage capacity across the state. Many are paired with solar farms in regional areas where coal plants once dominated.

One upcoming project includes a 350MW solar farm with 2.1GWh of battery storage—enough to power tens of thousands of homes through the night. These projects are timed to go live right as the last coal plants shut down in 2030.

The strategy contrasts with Australia's eastern states, where batteries have focused on shorter bursts of power for grid stability. Western Australia went bigger, building batteries that can store energy for hours and discharge it when the sun sets and families turn on lights and dinner.

The approach is working so well that Western Australia now sits alongside South Australia and California as one of only three places worldwide where batteries have powered more than 35% of peak demand. But Western Australia's grid is the largest isolated system to hit this milestone.

Energy coordinator Jai Thomas noted the 37.2% figure doesn't even count rooftop solar batteries at homes and businesses, meaning the real contribution from battery storage is actually higher.

This is what the energy transition looks like when it goes right—bold investments replacing retiring coal plants with clean technology that's ready to go when the grid needs it most.