(Note: This story has been updated to reflect the sudden fall in demand was due to outages at the Tomago aluminium smelter).
The anti-renewable lobby love to complain about the intermittency of “variable” renewable energy sources such as wind and solar, saying that it is impossible to manage on a large grid.
But there’s nothing quite so variable as demand … and the grid operator has been handling it just fine, as it has done for decades.
Just minutes before yesterday’s running of the Melbourne Cup there was a 1,000MW “cliff” in the NSW grid, as demand was suddenly lost.
It was first speculated that it was because of disappearing demand as punters took leave of their work stations and work places wound down. Turns out it was a sudden “trip” at the Tomago aluminium smelter which took three pot lines and more than  930MW of demand out of the system
As the graph shows, demand went from more than 8,200MW to less than 7,200MW in the space of five minutes, before gradually recovering over the next hour.
By the way, the big fall in demand on the previous day – though gradual – is an example of the so-called duck curve, where rooftop solar hollows out demand in the middle of the day, once one of the most profitable parts of the day for fossil fuel generators.
One of the differences between wind and solar and fossil fuels is that while the changes in output in wind and solar are quite predictable, sudden outages from coal and gas-fired plants and industrial users are often not.a
Giles Parkinson is founder and editor of Renew Economy, and is also the founder of One Step Off The Grid and founder/editor of The Driven. Giles has been a journalist for 35 years and is a former business and deputy editor of the Australian Financial Review.
Giles, the race was in Victoria, why are you talking about the NSW demand?
Or is it because yesterday was a public holiday in MEL and so offices were closed.
Or it could be that people who live in Sydney are not aware that Australia extends beyond Sydney’s boundaries.
i reckon there are a couple of people in NSW interested in the race. as you suggest, public holiday in Vic so no change in demand.
Where do you live Giles? 🙂
NSW
Jacob
The chart included in this post also shows a few days for VIC demand – you can see in this lower demand for VIC on the Melbourne Cup day:
http://www.wattclarity.com.au/2015/11/it-wasnt-the-horse-race-that-led-the-large-drop-in-load-in-nsw-coincident-with-the-race/
This would be due, at least in part, to public holiday
Paul
The WattClarity article says the horse race did not cause a dip in NSW demand. But then does not say what did.
Thanks Jacob
When I posted on WattClarity yesterday, I was aware of the cause – but was not aware that this was public knowledge (hence had to keep confidence).
Note in Giles’ article (above) that it was updated with more details…
Paul
So what you’re saying is a dispatchable grid can easily be redispatched. Thank you, that’s very helpful.
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