The Duck in California, and the Emu in South Australia
How the Residual Load of the System Actually Evolved When More Solar is Online with Energy Efficiency Taking Place
Read in other languages: 華文
I found an interesting graph on the evolution of the residual load curve in South Australia in May.
In 2012, the TSO in California published a famous report introducing the concept of “duck curve”, which described the observed and predicted characteristic of the residual load in California. Since then, it has been used to describe the similar situations around the world.
However, not all residual load curves evolved the same way as California; that is why some proposed to call the profile curve in South Australia the “emu curve”.
How has the Duck/Emu curve evolved in the past years?
For South Australia, the most interesting thing is the surge of residual load at midnight; traditionally heat pumps are turned on at that time because of the inflexibility of coal power plants.
In the future, it will make more sense to turn on the heat pumps during the midday. That would bring about 200MW of flexible demand.
For both curves, what is unexpected was that even the residual load peak in the evening dropped significantly due to a decreasing electricity demand. The energy efficiency programs in SA and California must have been quite successful.
This of course will reduce the need of conventional power plants to fill in the residual load gap in the evening. It also help ease the flexibility requirements. As another observer noted:
“…when the duck curve hypothesis was created, it assumed overall energy consumption would increase after the sun went down, and so bring pressure on the evening market… producing the elongated duck neck.
But in the absence of a feed in tariff that incentivises all generated electricity to be exported, it makes more economic sense for a solar panel owner to maximise self consumption — which is what they are choosing to do…
…Further, energy consumption across the OECD has been falling since the mid 2000s though gains in energy efficiency, but this trend was not properly recognised until about 2012, and was not recognised in the duck curve hypothesis when it was erected. The duck curve is not happening as predicted as the assumption of consumption was flawed.”
Solar Duck pancake
In short, the duck/emu curve isn’t as tedious as initially predicted. Furthermore, as storage becomes more and more significant and smarter demand management takes place, the duck and the emu can be well tamed in both California and South Australia.
This discussion around ducks and emus made me wonder what the residual load curve in Taiwan should be called. I will take the first pitch to call it the magpie curve.
