South Australians have so much wind power, too much, that in Quarter 3 last year the AEMO had to intervene to cut off excess wind and solar generation. Ever since the Great Blackout of 2016 new rules mean that there must be enough back up power running to cope with the fickle vagaries of intermittent energy. (Obviously, this wasting of sacred green electrons wouldn’t need to happen if people weren’t so persnickety about blackouts!)
This graph is from the Quarter 3 AEMO report for 2018. It is technically about both wind and solar, but it appears to be mostly wind. Solar is not a star player in Q3 because it’s winter.
Would we put up with any other industrial output that had such a dismal performance. Imagine this was your car….
Synchronous generation is the kind that comes from machines that spin at 50 Hz (like coal, gas, hydro, nukes). These keep the system stable. Happy happy hertz.
But ten percent of all the wind and solar power had to be thrown away in SA because there wasn’t enough reliable back up power to guarantee the stability of the system.
During Q3 2018, total curtailments of non-synchronous generation (large-scale wind and solar farms) in South Australia increased to around 150 GWh (or 10% of South Australian non-synchronous generation) (Figure 6), with curtailment occurring for 26% of the time during the quarter. This was the highest amount on record and around 70 GWh higher than the next highest quarter (Q3 2017). Key drivers were record high wind generation (Section 1.3.4) and insufficient synchronous generators being available to meet system strength requirements.
The reliable generators had gone home for the day (so to speak) because they couldn’t make enough money in a screwed market where intermittent and unsynchronised electricity is preferentially subsidized. So in order to make up for the damage done by a subsidy designed to drive fossil fuels out of business, we added another subsidy to keep them running. As you would.
The extra subsidy to counter the first subsidy cost $7m that quarter.
We may have the illusion of free market competition but increasingly the government controls more and more of the industry.
Over the quarter, AEMO intervened on multiple occasions to direct synchronous generation to remain online to ensure adequate system strength in South Australia and thereby maintain the grid in a secure operating state. On average, directions were in place for around 40% of the time during the quarter (Figure 5), with a cost of $7.4 million, which was $0.35 million higher than the prior quarter. This compares with directions in place for 50% of the time in Q2 2018 and 30% in the period since the system strength unit combinations were introduced in September 2017. Key drivers of system strength directions during the quarter included periods of relatively low prices (<$50/MWh) and high wind output (>1,100 MW) which resulted in synchronous generators seeking to decommit from the market for commercial reasons
After the SA system black, the AEMO brought in new rules which “… allow for wind to go up to 1200MW without restriction if three gas units are operating, and beyond 1200MW if four are offline.”
No wonder the renewables team want us to buy them a big Interconnector.