In a post on Monday, I advised readers to "pay attention to the news out of South Australia."  The prior week, on September 28, the entire state of South Australia was plunged into a power blackout in the midst of a major rain and wind storm.  Those who follow the subject know that South Australia has made a big thing in recent years of turning itself into the world leader of "renewable" energy, principally from the wind.  Immediately prior to the blackout, SA was getting some 50% or more of its electricity from its wind farms.  I have written several posts here (for example, this one) about how difficult it will be to make a fully-functioning 24/7/365 electricity system for a modern economy when production from intermittent sources like wind gets above about 30% of total electricity supply.

So was SA's blackout caused by over-reliance on the unreliable wind, or did it have other causes?  In my post on Monday, I merely raised the question, and did not attempt to answer it.  Instead, I linked to a source with information on all sides of the issue.  Others were less cautious.   The religious promoters of wind power immediately came forward to say that SA's dependence on wind had nothing to do with it.  For example, we had Karl Mathieson at Climate Change News on September 29 ("No, South Australian blackouts were not caused by renewables") and Josh Butler at the Huffington Post also on September 29 ("No, Renewable Energy Didn't Cause South Australia's Blackout").  The alternative cause put forward for the blackout was that high winds had knocked over several transmission towers.

Well, yesterday the Australia Energy Market Operator (AEMO) came out with its first preliminary report.  Here is the press release, and here is the full report (pdf).  Key quote:

Generation initially rode through the faults, but at 16:18hrs, following multiple faults in a short period, 315 MW of wind generation disconnected, affecting the region north of Adelaide. The uncontrolled reduction in generation increased the flow on the main Victorian interconnector (Heywood) to make up the deficit and resulted in the interconnector overloading.

Translation:  nearly all the wind generation conked out all at once as high winds made it dangerous for the turbines to keep operating; and the back-up sources could not kick in quickly enough, let alone that the transmission lines to bring in the back-up power promptly got overstressed.  So the whole system went down.

Did the felling of a few transmission towers contribute in some way?  I'm not sure that that has yet been completely ruled out.  But the real question is, how much extra back-up (fossil fuel or nuclear) capacity do you need to have, and how much extra transmission capacity do you need to have, if you are going to have an electricity system getting half or more of its power from wind and hope that it will withstand major storms?

Here's a further substantial post from Australian blogger Joanne Nova.  Key quote:

The bottom line is that wind energy comes at a very high cost and makes the system either very expensive or horribly fragile or both. Given that wind farms aren’t providing cheap electricity — when the infrastructure and the costs of having back up “spinning reserve”  and baseload is taken into account — what’s the point of adding all this risk to the system? To change the weather?

Meanwhile, back home here in New York, we just committed in August to a new "renewable portfolio standard" of getting 50% of our electricity from "renewables" by 2030.  Brilliant!  Has anybody even considered the question of whether or how this thing is actually going to work?  The good news is that between places like South Australia, and others like Germany and Denmark that haven't had a big disaster yet but are operating very much on the edge, we are likely to have some bad experience of others to learn from before we dig ourselves too far into this hole.