Australia’s first 2GWh battery is aimed at eliminating a very big solar duck curve

Western Australia is one of the most fascinating grids in the world when it comes to the transition from fossil fuels to renewables.

It’s not the most advanced in the uptake of renewables – South Australia has double the wind and solar penetration with a 12-month share of 70 per cent – but what makes it so interesting is the fact that W.A. main grid is still big, and completely isolated. It can’t share with other grid if it has too much, or too little supply.

After a multi-year investment drought deliberately encouraged by the previous Coalition government, the boost switch to green energy has been well and truly pushed – by consumers, by industry, and now by the government.

Western Australia already has one of the highest penetrations of rooftop solar in the world, and now industry is pushing for vast amounts of new wind, solar and storage to support its plans for significant zero-carbon industry, essential to meet the supply chain demands in a world accelerating to net zero.

The state government has recently paid out the demand potential for this new industry in a roadmap that estimates it could need more than 50GW of wind, solar and storage.

But it is already moving quickly – from a standing start – to find ways of storing the excess rooftop solar that is proving increasingly difficult to manage, and causing other renewable energy sources to be heavily curtailed in the midday sun.

Last month it started operations at the first big battery to be built on the main grid, a 100MW/200MWh facility at Kwinana, and this week won planning approval for a second stage battery at the same site – 200MW and 800MWh, or four hours to storate.

State utility Synergy, which will own both batteries, is also marketing its even bigger battery venture – a 500MW/2000MWh facility at the coal town of Collie, that will be the first battery of this size in the country, and quite possibly the world (depending on timing).

At a recent community meeting in Collie, Synergy officials presented the graph above, highlighting the issue that the state is trying to address. The growth of rooftop solar is so rapid that it visually eliminated daytime demand in sunny conditions.

Within a couple of years, rooftop solar could be producing some 500MW more than daytime demand – the choice is either to force the solar to be switched off, or to store it.

The state has clearly decided that the smartest, and ultimately the cheapest and most efficient thing to do is to store it. And the scale of the problem clearly demands a battery of the size proposed for Collie, whose remaining coal generators are scheduled to shut down by the end of the decade.

This massive storage will ensure that the market operator still has access to the necessary tools to keep the grid stable during the rooftop solar day-time hours, and the evening peaks.

The Collie battery is expected to be built by the end of 2025. It is part of a $2.8 billion commitment for battery storage and also for more wind power, including a new wind farm at King Rocks and an expansion of the Warradarge facility.