AEMO to allow more wind and solar in South Australia grid, needs less gas

The shackles on large scale wind and solar farms in South Australia are about to be loosened, with the Australian Energy Market Operator flagging that the maximum amount of large scale wind and solar allowed into the grid at any one time will be lifted by around 15 per cent.

AEMO’s current operating constraints allow for no more than 1750MW of large scale wind and solar (plus rooftop solar) to be generating at any one time, and for a certain amount of gas generators (usually around 300MW) to be operating to provide essential grid services.

Those restraints are about to be relaxed, and up to 2,000MW of wind and solar to generate at any one time, because newly installed synchronous condensers that are to come on line soon will provide some of the “synchronous” system services now provided by gas generators.

The current constraint has not stopped wind and solar providing more than 60 per cent of South Australia’s electricity demand over the last 12 months, and more than 100 per cent at certain times – usually from wind but also just from solar on occasions. See “World first”: South Australia achieves 100pct solar, and lowest prices in Australia

However, at times of strong winds and good sunshine, large scale wind and solar often has to scaled back to meet those grid constraints, which often lead to negative pricing events. Gas generators often have to be “directed” to stay on line to ensure the services are provided.

The two new synchronous condensers will begin operating at Davenport, near Port Augusta, close to the now closed Northern coal generator, at the end of April. Another two syncons – spinning machines that do not burn fuel – will come on line at at Robertstown at the end of May, allowing for constraints to be eased further and more wind and solar to be generated at any one time.

South Australia currently has around 373MW of large scale solar, and more than 2,050MW of large scale wind capacity, but this will grow significantly over the next year with the 320MW hybrid Port Augusta Renewable Energy Hub near Port Augusta currently under construction, the second stage of the Lincoln Gap also being built, and the first 100MW stage of the massive Goyder South project also starting work, along with the 260MW Whyalla solar farm.

But there are many gigawatts of large scale wind and solar in the pipeline, some of them waiting for confirmation that the proposed new $2.4 billion link from Robertstown to Wagga Wagga in NSW, the 800MW Project EnergyConnect, will be built by 2023 or 2024.

The South Australian government has a target of “net 100 per cent renewables” (wind and solar) by 2030, but experts suggest it will reach that milestone before then. The government has a longer term target of 500 per cent renewables, or about 12GW of installed wind and solar capacity, as part of its plans to become a net exporter of clean energy, either through transmission links or the three green hydrogen hubs that it plans to create.

For those wanting more detail, energy expert Allan O’Neill canvasses the impact of the syncons, and other grid constraints, in this detailed analysis at WattClarity.

“The first key point here is that the limits on total non-synchronous generation – under “system normal” conditions, when there are no relevant transmission outages that might tighten the system security envelope, move to relatively high levels of 1,900-2,000 MW, compared to current limits of 1,300-1,700 MW very frequently observed in December (and in many other months),” he writes.

“This makes it seem very likely that after commissioning of the syncons – and assuming that these devices run more or less continuously – the updated system strength constraint will bind much less frequently than seen recently. (At least until additional renewable generation is commissioned in South Australia.)”

Around one dozen syncons have been installed elsewhere in the main Australian grid, but much of this has been on an “ad-hoc” basis under the controversial “do no harm” rules that network operators have criticised, and have suggested make the grid less stable rather than more secure.