South Australia’s growing fleet of big batteries has hit a stunning new milestone – grabbing a world-leading 40 per cent share of instantaneous demand in the evening peak on Tuesday in Australia’s most advanced renewable grid.
The new milestone was recorded by both GPE NEMLog and Open Electricity, with the two grid data providers having slightly different figures – 39.6 per cent in the case of the former and 40.1 per cent in the case of the latter.
Both came at 7.55 pm, when they agreed that a record 611 MW was being delivered by the state’s battery fleet. The new record share is significantly higher than the previous peak of 37.4 per cent in early October and just over 20 per cent a year ago, according to GPE’s Geoff Eldridge.
The dominant role of battery storage relegated gas-fired generation to a mere 5 per cent, or 83 MW, according to Open Electricity. Wind was contributing 1,350 MW at the time, rooftop solar just 6 MW and 529 MW was being exported to Victoria and NSW.
The new record share of around 40 per cent beats California’s recent record peak of 37 per cent – reached a month ago – and highlights the rapidly evolving nature of grids with a high share of renewables.
South Australia leads Australia, and the world, with a record share of 75 per cent wind and solar (averaged over the past year), and a world-leading target of reaching 100 per cent net renewables by the end of 2027.
Smaller mini grids – such as those in remote towns and mine-sites – have reached higher shares of wind and solar, but South Australia is the first gigawatt scale grid in the world to reach such levels.
South Australia was, of course, the first grid to host a major big battery with the installation of the “Tesla Big Battery” at Hornsdale in late 2017.
Since then, that project has been expanded, and seven others have joined the grid, with more than a dozen others already under construction or committed.
The latest – announced on Wednesday – is the 200 MW, 400 MWh Pelican Point battery, which is being built in place of a planned third turbine at the neighbouring gas generator.
The first big batteries at Hornsdale and Dalrymple North were mostly focused on providing services such as frequency control and system protections, acting as a kind of shock absorber to the grid.
These have been followed by the addition of grid forming inverters that allows those batteries to provide other critical grid services such as synthetic inertia and system strength.
But the sheer scale of the batteries is now allowing for more time shifting of excess wind and solar, leading to a greater share of renewables and fewer constraints, although levels of curtailment still remain high.
This is being supported by the construction of a new transmission link to NSW, which will help the state run at times “engine off”, with no fossil fuels.
The market operator still requires at least one gas unit to be running at all times to ensure grid stability, but that need will soon pass, thanks also to the installation of four large spinning machines known as synchronous condensers.
Some batteries have specific roles, such as the Blyth battery – so far the state’s biggest, built by Neoen – that is helping provide a steady power feed for BHP’s giant Olympic Dam mine. The new Goyder battery, next to the Goyder North wind project, will have a similar role once complete.
Eldridge notes that growing share of battery discharge is a sign of things to come in South Australia and more broadly in the National Electricity Market.
On Tuesday, there was virtually no large scale solar fed into the grid during the day, as it was curtailed due to the impact of rooftop solar PV and negative prices.
More batteries are likely needed to soak up that power, and Potentia Energy is believed to be considering one such addition next to the state’s biggest solar farm at Bungala, near Port Augusta.
Meanwhile, the growing impact of rooftop solar is having an impact on other parts of grid management, with the market operator posting near daily alerts on “minimum system load” in the past few weeks.
Already, on at least three occasions, the market operator has had to issue directions to a big battery – in these cases the Torrens Island battery – to discharge and sit on standby in case it is needed to charge up and create demand for the grid operator to maintain grid security in case of a disruption.
Nearly all new large scale solar farms are now being built as solar-battery hybrids, with big batteries sharing the same connection point and storing excess solar during the day so it can be injected into the grid in the evening. It likely means that sometime soon the bulk of the evening peak will come from stored solar.