Wind Power Generation Intermittency – It’s Worse Than You Think It Is – Part Three

Posted on Mon 11/30/2020 by


By Anton Lang ~

Sustained Power Loss Over Longer Time Frames

I showed and explained in Part Two how the weather itself has an impact on wind power generation intermittency over short time frames, and the same applies for power losses over longer time frames, only for a completely different reason. With those short time frame losses in power, that was due to the wind being too high, and the towers turning off at the upper wind speed level. When it comes to these longer time frame power losses, this is due to the opposite happening, wind towers turning off because the wind is too low. Whereas with the short time frame power losses, they happen very quickly and result in power losses equating to hundreds of wind towers turning off, hence very fast losses of power. Now, with these long time frame losses, those falls in power may look to be gradual in nature, so not as much in a short time, but what does happen is that power generation falls away continuously, and just keeps falling, sometimes to the point where very little power is being generated by the whole range of EVERY wind plant in the Country, and, as with those short term power losses, this long term sustained losses of power is also something I can show you as well.

Now, here again, you might actually think of this as being quite a rare thing, but it actually is quite prevalent. It happens when those large High Pressure weather systems move over the areas where there is a concentration of wind plants, and here, the largest concentration of wind plants is in that area of the Country I explained about in the earlier Posts, a large area covering South Eastern South Australia, and Central Western Victoria. As those large High Pressure systems move into that area, the large central area of that system just sits there directly over the top of all those wind plants. Because there are no isobars, then there is no wind, and as long as that system sits there, then there is virtually no wind, and all those wind towers at all those wind plants just turn of, so there is very little, and sometimes even no power generation at all.

Power loss between three and eight and a half hours

With all the images of the graphs and maps shown here, if you click on the image, it will then open on a new page at a larger size so you can better see the detail.

Here, there were 42 occasions when this happened starting in May of 2018, and the losses in that time frame between three and eight and a half hours were between 1200MW and 2490MW. (Here, there were in fact a lot more occasions than these 42 that were between 500MW and 1200MW, but to keep the list relatively shorter, I used the start point of 1200MW, otherwise there would have been hundreds) Keep in mind here that this start point of 1200MW equates to the loss of around 600 or more individual wind towers, and that upper mark of 2490MW is around 1300 wind towers, so around 15 or more wind plants.

As you view each of these images, be aware of the scale change for the left side vertical axis. So even though the graphs look similar, they have been sized to best fit the original page they were shown on.

This first image is from 01October 2018, and this shows a power loss of 2000MW across seven hours. Here, I have placed the marker at the top of the fall, and that is at 2336MW, and the low point is just after 14:00. (2PM) Here, keep in mind this was when the total Nameplate was a lot lower than it is now. Even though there was a small rise it, still fell sharply across that time frame, and this loss of that 2000MW, equates to around a thousand or so individual wind towers, and 20 or more separate wind plants in that one area.

This second image shows the largest power loss for this time frame, and this was on 06October 2019, and this was a power loss of 2490MW over eight hours and forty minutes. In the intervening year, overall Nameplate had increased. Again I have placed the marker at the top of the fall, and that was 3508MW at 3.05PM, and the loss of power eases off at 11.45PM, just prior to Midnight. That sustained loss equates to around 1300 individual wind towers with their blades stationary, a loss of as many as 25 wind plants.

This third image shows a more recent power loss, from 23June 2020, and this shows a power loss of 1760MW. Even though the total Nameplate for wind power has increased, this graph does not show the increasing nature of total power generation, (this one similar to the second graph) and I have included this graph only to show how the time frame of the loss has shortened. Now, while this loss of power is only mid range on the table of power losses for this time frame, this loss was over a shorter time period, losing this 1760MW in just five hours and 40 Minutes. Most power losses over that 1700MW total were all across longer time periods for those earlier dates on the table for this time frame of power losses. Again, the total Nameplate has risen to the most recent total of 7728MW. What this indicates is that with the addition of more wind plants in this area, then, when these High pressure weather systems come into the area, that loss of power has become greater, more prevalent, and faster in the duration of the fall. Here, I have included the Synoptic chart for this same day, and as you can see, there are two of those High Pressure systems just about to join into one larger one, and it is sitting directly over that area where there are the largest number of wind plants.

Sustained power loss over long time frames of nine hours and longer

This is the last of these power loss versus time, and here, I want you to consider this. There were 64 of these events, and keep in mind here that the period this data is recorded over is around 800 days, so effectively, that’s one of these sustained losses of power every 12 days, and then add on every other loss from all of the previous time frames as well. These sustained falls are a loss of power from a high level of generation back close to zero generated power. I have only included those power totals starting at 1500MW (with just two which are slightly less than that) and the largest fall is 3670MW, and of those larger falls, ten of them are 3000MW and higher. That fall of 3670MW is around 1950 individual wind towers and also almost 40 wind plants.

What is the difference between this sustained loss over long time frames and the earlier one above up to eight and a half hours? These are very large High pressure weather systems, that move very slowly across the area where the largest number of these wind plants are located. In the earlier time frame above, those High pressure weather systems were not quite as large in size, and moved across the area a little more quickly. Because these ones for this time frame are so large, they are slow moving, so the loss of power is sustained over long time frames from nine hours upwards, and the largest one I recorded was 27 hours, and there were 17 of them where the time frame was spread across two days. Those losses which are spread across two days are images I cannot show you, as they are over those two days, and as I mentioned in red above, the scales are different on days like those so the images best fit the graph they are shown on.

This first image was taken on 31 May 2018, when the total Nameplate for wind power was a lot less than it is today, and at that time, that Nameplate was around the 5000MW total. This graph shows a sustained loss of 1630MW in the ten hours from that little blip just after Midnight. As you can see for these sustained losses, I have now placed the marker on the low point, and here that is at five past ten and at 600MW, and the drop started at a level of 2630MW. You can see that other than that small uptick, the fall was sustained at a relatively constant rate. Now, why I have placed that marker at the low point is to show you that low power generation total, when viewed in conjunction with the Synoptic chart of this same day. On that Synoptic chart, note the time in the bottom left box of the map image at 10.00AM AEST, the exact time of that low on the power generation graph. The centre of that very large High pressure system is directly over the area where there are the largest number of those wind plants. So, in effect, very little power is being generated by those plants and the only power being generated is from the plants in the other three States. This loss of that 1630MW is around 800 plus individual towers and around 16 to 20 wind plants, all of them back to zero output.

Wind Generation Sustained Power Loss

This second graph is from 22Aug 2019, and shows a very long sustained power loss of 3670MW over 20 hours and 40 Minutes. It starts at just before 1.00AM with the power generation at a high of 4520MW, and falls at a high rate across the day to a low of that 850MW where I have set the marker at just after 11.00PM. Again that huge loss is around 1900 individual towers out of action from almost 40 wind plants. Again, view this power loss in conjunction with the synoptic chart, showing that large High pressure weather system directly over the same area, and while the time of this weather image is 10AM, that is half way down the graph showing power loss, as that system moved further Eastwards over the next 12 hours. For some perspective here, that loss of the 3670MW is the equivalent of taking out the whole six Units at the Loy Yang coal fired power plant in the State of Victoria. That coal fired plant with its six Units has a Nameplate of 3210MW, so less than the total Nameplate loss for wind power across these 20 hours. If those six coal fired Units went off line in that same time frame, the whole State of Victoria would be blacked out. Something like that, the loss of all six coal fired Units in that time frame would be viewed as a catastrophe, literally, and yet when something like happens with wind generation, no one says a thing, and in actual fact, no one even knows it even happened.

This third image is again one of the most recent ones, when wind power now has a total Nameplate of 7728MW. This graph is taken from 03June 2020, and shows a power loss of 2550MW in 14 hours and 20 Minutes. It starts at just after 1.00AM where you can see the peak of just a little less than 3600MW and drops to that marked low of 1027MW at 3.45PM. Again, the fall is fairly constant across that time period, with just a couple of times where it rose a little before falling again. This power loss of 2550MW is around 1300 individual wind towers and around 25 wind plants, all back to zero. The synoptic chart again shows a large High pressure weather system directly over this area where there are those large numbers of wind plants, and again, while showing the time stamp at 10AM, it was moving very slowly Eastwards across this area.

Again, this shows just three of those 64 separate occasions where there has been a sustained loss of power over an extended period of time.

Now, if none of that convinces you, I have one last graph to show you. This one is also a recent one, taken from 26June 2020. This shows a larger graph, as under the graph, you can see the ticked boxes for the wind plants in question, and under that, right along the bottom, you can see the States listed there, and the only two States I have ticked are South Australia, and Victoria. and above those States, are the coloured boxes indicating each individual wind plant in those states. There are 45 Wind plants in those two States, (22 in South Australia, and 23 in Victoria) with a total Nameplate of 4916MW, and all up, that’s 64% of the total Nameplate for all wind power in the whole of Australia. That’s around 2500 individual wind towers. Now, what the graph shows is that at the indicated mark at 6.30PM, (incidentally, the same time as the usual evening peak power consumption is happening) those 45 wind plants in those two States are generating ZERO power, in fact, they are even drawing power from the grid.

The synoptic chart shows the date and time, at the bottom left at 4PM on this day, the closest chart for the zero power time, and again, as you can see, that large High pressure weather system is right on top of that area where all those wind plants are in South Australia and Victoria.

45 wind plants – ZERO POWER.

Did you hear about this? Was it mentioned in any media outlet? Did anybody even know it happened?

Victoria has ten coal fired Units in total, and the Nameplate for all of them is 4690MW. The Nameplate for the wind plants in both States is 4916MW, and ALL of them were delivering zero power, a greater loss than ALL the coal fired power in Victoria. If all ten coal fired Units went off line in Victoria, the State would be blacked out, and with no wind power in South Australia, and knowing their reliance on the Interconnector to Victoria, then South Australia would also be blacked out. Without a shadow of a doubt, you WOULD certainly hear about that. They would shout it out from every media outlet, how coal fired power was unreliable, and cannot be depended upon to supply power, and in utter irony, the answer from the renewables lobby would be to construct more wind plants, and here, the loss of power from those wind plants was greater than the loss of ALL those ten coal fired Units.

These two States are where most of those new wind plants have been constructed over the last two years, when the total Nameplate for wind power has increased by almost 3000MW. So, instead of spreading out the location of those wind plants to hopefully alleviate the problem of intermittency and power loss, they have instead concentrated it, and made it worse. So now, when they have these weather problems, both with high wind situations and low wind situations, the power loss is greater for both occurrences, it happens more quickly (high wind) and lasts longer. (low wind)

Here we have 265 separate occasions where wind power has gone missing across only 800 days, and this is not small losses, as the minimum loss is 500MW, and as many as I have detailed at that high power total of 500MW, there were as many in smaller ranges as well.

You can call it intermittency, you know, up and down, a little bit here, a little bit there. Well this is most definitely NOT that.

This is the outright loss of large amounts of power. If it happened with any other source of power generation, especially from coal fired power, they would be screaming it out constantly. The point here is that it is not happening with coal fired power anywhere even remotely close to this scale with wind generation.

It IS happening with wind power, and what do you hear about it.


The time has come to start telling the public how big a failure wind power really is.


The two tables for each of those time frames are at the links shown below. Each Table is a pdf document. When you click on the link, the table will open in a new window.

(a) Loss of power between three and eight and a half hours.

(b) Loss of power over long time frames of nine hours and longer.

The first column is the date of the fall in power. The second column is the size of that fall in MegaWatts (MW) and the third column is the duration of that drop in power from when it started to when it settled at the new lower level.


Anton Lang uses the screen name of TonyfromOz, and he writes at this site, PA Pundits International on topics related to electrical power generation, from all sources, concentrating mainly on Renewable Power, and how the two most favoured methods of renewable power generation, Wind Power and all versions of Solar Power, fail comprehensively to deliver levels of power required to replace traditional power generation. His Bio is at this link.