Solar power continues to set stunning new milestones in the renewable state of South Australia, reaching 80 per cent of total demand on Saturday and accounting for more than 70 per cent of demand over four hours in the middle of the day.

The 80 per cent share (well, 79.6 per cent actually, but we are rounding up) was reached at 1.10pm (network time, AEST) on Saturday, with rooftop solar providing the bulk of the output – 819MW or 63 per cent of state demand – and utility scale solar (Bungala 1, Tailem Bend and the partially complete Bungala 2) providing a combined 219MW, or 17 per cent.

While that took solar’s total share of demand to 80 per cent at 1.10pm, according to the OpenNem website, its share of total generation at that time was closer to 66 per cent (see second graph), with just over a quarter of the total coming from gas generation. The excess over state demand was exported to Victoria, as it was for most of the week.

The interesting thing about this new milestone is that it means it will not be long until solar output is high enough during some daytime hours to meet all the state’s demand. Bungala 2 is currently on a “hold point” position (as it has been for a long time), that limits its output to around 20MW.

But if and when Bungala 2 satisfies AEMO requirements and reaches its its full rating of 120MW, and Sanjeev Gupta’s 280MW Cultana solar farm comes on line, and more rooftop solar is added, as is inevitable, then the total output of solar will inevitably exceed total demand on some occasions. AEMO has warned that rooftop solar alone could do that within a few years.

Given the new wind farms being built (including the 214MW Lincoln Gap), it will be interesting to see what happens to the gas generation when the four synchronous condensers are installed next year by ElectraNet.

These spinning machines do not burn fuel, but provide the spinning mass that AEMO says is needed to maintain system strength. This will allow more gas generators to be switched off when not needed for electricity output.

The state Liberal government has a target of net 100 per cent renewables and become a major exporter of renewable power. It says this net 100 per cent target will meet by 2030, or soon after, but it will likely be met earlier given the huge pipeline of projects.

The government, and AEMO, will be hoping to see more examples of the complementary qualities of wind and solar output as occurred in near, but not quite perfect sequence in South Australia over this past week. Wind generated mostly at night, while solar provided the bulk of output during the day, although they didn’t quite get the handover quantities right in the early evening.



There was enough wind an solar to meet 100 per cent of state demand on some occasions, and 67 per cent of local demand across the week, a percentage that will grow significantly as more projects are added.

Of course, gas generation will continue to be needed when the combined output of wind and solar is insufficient to meet local demand. Shorter term storage will help remove the pricing peaks that occurred this past week in the early evening, when the sun sets and wind generation hadn’t yet ramped up.

But given the huge quantities of new wind, solar, and pumped hydro and battery storage projects, and even hydrogen plants, that are in the pipeline in the state, then the role of gas generation may be reduced to just a series of fast-start generators.

That’s why AGL is building two new fast-start generators at Barker’s Inlet , and plans to close down capacity at Torrens Island, although part of this closure has been delayed for one summer to ensure the transition is smooth. Infigen and Nexif plan to lease and operate the state-owned fast-start generators in a similar way, alongside the wind and battery storage assets they own.

A new transmission line is expected to be built between Robertstown in South Australia and Wagga Wagga in NSW, which will increase South Australia’s ability to export excess capacity, and to import when needed, as well as an added back-up to the current line to Victoria.

This is also expected to unlock a huge amount of new developments, including Neoen’s Crystal Brook and South Goyder projects, and the Solar River solar and battery project that has already secured a power purchase agreement with Alinta.