We have enough renewables to reach 100%, but coal is in the way
Australia’s renewables could generate more than enough electricity to power the entire grid for a brief time over the June long weekend.
Unfortunately, a variety of factors including negative pricing events and the presence of inflexible coal fired generators got in the way.
The grid hit new records over the weekend, including the lowest levels of coal output.A record was also set for low grid demand, thanks to rooftop solar which accounted for more than half of generation at various times.
The high level of actual renewable generation was massively curtailed – 7796 MW at 1140 am (AEST) on Sunday.
If this curtailed output had been allowed to flow, renewables would have delivered enough output to provide 101.4% of grid demand at the time.
That's a record for renewables production plus curtailment – up from the 100% of demand first reached on September 16 this year, which was a big leap from the 90% recorded last November.
Five years ago, the maximum level of renewable production plus curtailment was just 26%, although in those days very little needed to be curtailed.
When AEMO released its engineering roadmap to 100% renewables in July, it expected that instances of 100% renewables could happen as early as 2025 - so these results are clearly a surprise.
So, why were the wind (3,182 MW) and large scale solar (4614 MW) curtailed?
Mostly it was because of negative prices, and contracts which require some of those facilities to switch off when prices go below zero.
But AEMO says it isn't yet ready to accommodate periods of 100% renewables, because it still has a long list of engineering and operating protocols to put in place.
There are four key areas of focus – managing distributed energy like rooftop solar, new technologies like grid inverters, more power system studies, and “operational readiness.”
Some Australian state grids already operate at 100% renewable or more on occasions.Tasmania, for instance, does this on an almost daily basis thanks to its hydro resources.