South Australia gets 40% of its electricity from wind and solar
Of all the Australian states, the South has the most wind and solar capacity per person. Wind power generates electricity equal to about a third of the state’s total consumption and rooftop solar generates about 6%. All up, South Australia gets about 40% of its electricity from wind and solar.
Negative electricity prices
On Tuesday the 30th of September, South Australia managed to go most of the working day with enough electricity generated by wind and solar to meet all demand, and electricity prices went negative for a considerable period that morning (see graph).
Grid demand started off very low at 5 a.m. but soon increased as people woke up and started to cook breakfast, cows were plugged into electric milk sucking machines, and bakers eagerly shoved their thick sticky dough into hot ovens.
But then, at about 9:15 or so, demand for grid electricity started to fall. This was not because people were using less electricity but because production from rooftop solar was increasing and this doesn’t show up as grid demand but subtracts from it.
By about 11:30 grid demand was lower than it had been in the earlier hours making almost the middle of the day our new off-peak time.
At 12:00 rooftop solar would have been providing about 28% of the state’s total electricity use.