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at #4574Tingting ZhangKeymaster
In the electricity grid, the transition to green energy is usually incremental. Growth in capacity and production is measured in megawatts and megawatt hours, while the changes in the share of fossil fuels and renewables ebb and surge in fractions of a percentage point.
That’s what makes the great leap forward in South Australia all the more significant. On eight consecutive days in late October, the state reached a level of more than 100 per cent wind and solar.
But the big event was news that the shackles are being released on the constraints imposed on the state’s vast and growing resources of wind and solar power. Until now a cap had been imposed for fear there was not enough “synchronous generation” to keep the grid stable.
On Monday 25 October it reached 100 per cent renewables on solar only. On Friday 22 October and again on Friday 29, it did the same trick with wind only. Indeed, at 2.05am on Friday 29/10, wind set a record share of 128.2 per cent of state demand, beating the previous record of 126 pct, according to Geoff Eldridge at NEMlog.
That meant limits on how much wind could be produced at any one time, depending on prevailing demand, generation and the state of the transmission links to Victoria. Wind and solar had to make way for sufficient gas to be generated if needed.
That’s no longer the case. On Monday 25 October the local transmission company ElectraNet announced that the installation of four synchronous condensers had been completed at Robertstown and Port Augusta.
These big spinning machines mimic the actions of gas generators, without burning any fossil fuels. Their mere presence means the limits on wind and solar can be relaxed – in certain conditions – to up to 2,500MW. That’s more than the current installed capacity, but not for long.
Keen grid watchers quickly noticed the changes. On Tuesday 26/10, one watcher noted, South Australia moved on from its normal limit of 1,300MW without ramping up the amount of gas generation.
It’s interesting to note that in the past year South Australia has averaged 62 per cent wind and solar, a world-leading figure. In the month of October, that share has jumped to 72 per cent, mostly due to seasonal factors, and mild weather.
In one week, the share of wind and solar went up to 81 per cent, and in three days of that week it jumped to 85 per cent, helped by the relaxation of grid constraints on the output of renewables.
The SA government has a target of “net 100 per cent” renewables by 2030, but it is likely to reach that target well before then.
There will still be constraints on the output of wind and solar, but these will mostly be economic, and will mostly focus around the need for wind and solar farm owners to dodge negative pricing events – now mostly caused by the growth of rooftop solar – as much as they can.
The long term solution for those problems will be storage, new transmission links, and new load, such as the renewable hydrogen projects being contemplated, or the switch to renewable contracts like that of BHP, which will now source half of the power needs for its Olympic Dam mine from wind and solar.
Further leaps will come with the opening of the $2.3 billion project EnergyConnect transmission link to NSW, which will inspire a number of other wind and solar and storage projects to be built.
Batteries, operating in “virtual synchronous machine” mode are likely to negate the need for more syncons, and will offer multiple other grid services and flexibility too.
By: Giles Parkinson
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