At about the same time as the running of Victoria’s Melbourne Cup race on Tuesday, energy market watchers were given a lesson in electricity variability – not the variability of solar and wind generation, but the variability of demand, and how the grid operator handles 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.
© 2015 Solar Choice Pty Ltd