Category Archives: Energy

Our new Federal Government

While I was blogging about the grid batteries in South Australia, we got a new Federal Government. It took a while, we were without a functional Federal Government since December 2018 when the then coalition broke up. This new coalition consists of seven parties from four different political groups. This Frankenstein coalition want to be called the “Vivaldi” coalition (after the violin concertos “The Four Seasons” by Vivaldi, representing the colors of the four political colors of the groups in the coalition). To make such a coalition work, compromises had to be made and also political presents had to be given.

Probably one of those presents is that the Minister of Energy is provided by the Green party. Our Minister of Energy now is Tinne Van der Straeten and the readers of this blog know her as the politician who managed to increase, ahem, fossil fuel subsidies and the Green party was apparently proud of that achievement.

The new coalition is very ambitious. When it comes to energy, they aim for the closure of the nuclear power plants by … 2025. To put that in perspective, our nuclear plants currently produce almost half of our electricity and this amount of power needs to be replaced within the next five years (it took decades to come to ten or so percent of solar and wind). They want to do this replacement by stimulating intermittent technologies, cooperation with neighbor countries (increased import and export), energy saving and also some gas-fueled power plants will be needed too. At the same time they also want to make energy cheaper, ensure energy security, create more jobs and lower emissions. All this without having to increase taxes…

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The fingerprint of solar and wind on import/export balance

The subject of previous post is how South Australia, having a high share of solar and wind, balances its grid. While crunching the numbers, I noticed that there generally is more import when electricity production by solar and wind is low and that there is more export when electricity production by solar and wind is high. This reminded me of a post I wrote about the German Energiewende in which I looked at the import/export balance and compared it with solar, with wind, with solar plus wind and with lignite. The import/export balance clearly followed the solar plus wind curve, but the peaks were somewhat topped off.

This made me wonder whether the same is true of the South Australia data. Let us first look at the same graph from previous post, but overlayed with the import/export balance curve in red (click to enlarge for a much clearer view):

AEMO South Australia charts0011b Fuelmix vs import export balance small

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About intermittency and being a net exporter

While writing the post on the upgrade of the Hornsdale Power Reserve, I became curious how South Australia balances its grid. Looking into the data, it became pretty clear that it aren’t the batteries that doing the balancing. According to the fuel mix data of AEMO, the battery storage output is insignificant compared to the huge swings in output of solar and wind power.

There are several balancing strategies possible. For example, in a previous series on the German energiewende, I found that Germany’s strategy is to use fossil fuels (gas, coal and even lignite) when there is not enough solar & wind and export the surplus to the neighboring countries when there is too much solar & wind.

South Australia also has a high share of solar and wind, so how do they do it?

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When solar and wind capacity increase

When pointing to the huge fluctuations of solar and wind production in previous post, I wrote that these fluctuations will only grow when South Australia advances on its path towards 100% renewable energy. Looking at the fuel mix and demand data that I had gathered until then, I noticed a fine example of exactly that. Just look at the fuel mix and demand data:

AEMO South Australia (charts0011a) overview

Let’s focus on the minimum on September 5 at 20:00. That is around the time that I looked for the first time at the overview panel (see previous post). The data showed that the total production of solar and wind was 4.341 MWh, which is 0.29% of what was produced at that moment. Contrast this to the peak of 1,258.486 MW the next day around 22:00, just after the evening peak when energy demand was slowly starting to decrease. It is this dynamics that will lead to the fluctuations that I wrote about.

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Hornsdale Power Reserve: the share of battery power in South Australia

The Hornsdale Power Reserve is about to get an upgrade. The Hornsdale Power Reserve is a grid-sized battery build by Tesla in South Australia. It has a capacity of 100 MW and can deliver 129 MWh. I did a series on it back in March, starting with the claim that this battery could replace natural gas for peaking and gap-filling (which is not the case). The upgrade will add a capacity of 50 MW and it can deliver 64.5 MWh.

The pv-magazine article points out that the additional capacity will be put to use for frequency control and inertia. I could understand that, the main function of the original 100 MW battery is already frequency control and this service generated quite some money for its owner. There was also this claim (my emphasis):

ARENA, which contributed an AU$8 million grant toward the expansion, also believes the upgraded battery could also help to reduce renewable curtailment in South Australia. Indeed, AEMO’s Chief System Design and Engineering Officer, Alex Wonhas, said that the expansion enabled the “optimal use of this world leading battery to support higher levels of renewable integration.”

The author also didn’t shy away from using terms like “mega” and “highly successful” in the article. That all sounds very promising, but from looking into the Hornsdale Power Reserve while writing the earlier series, I think it is presented way nicer than it actually is. Even a “mega”-battery of 100 MW / 129 MWh is still tiny grid-wise and adding another 50 MW / 64.5 MWh will probably not make much of a difference.

This made me wonder: what is the current share of battery power in the South Australia grid? And what difference would this upgrade make once it gets online (the homepage of the Hornsdale website states that the expansion is still “under construction”)?

Time to look at the data.

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Wind keeping the system “nicely balanced”: does more wind power means better air and cleaner electricity?

Let’s continue with the open letter from the energy company Eneco (see previous post), in which its CEO complains that his company “felt obliged” to shut down some of their windmills despite it was windy. It is framed as the result of the “inflexibility” of nuclear power that pushes wind aside and, most importantly for this post, as a choice for better air and cleaner electricity (translated from Dutch, my emphasis):

Renewable energy could provide half of our consumption. In itself this is a good prospect: better air and cleaner electricity from wind & sun. We should all be pleased with that.

The framing in the open letter made me wonder how much wind power was curtailed exactly? Also, assuming that nuclear power would get turned down a notch during the lockdown, how much cleaner would electricity production then get?

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Wind keeping the system “nicely balanced”: wind, meet nuclear

Never could imagine that the words “wind energy” and “nicely balanced” would be used in the same sentence. This was achieved in this tweet (for the international readers, “BE” is the country code for Belgium):

BE update: Wind offshore dropped as of 10am, onshore as of 11am. And it is keeping the system nicely balanced. But of course, if only we could have dynamic demand response to this, society wouldn’t have to loose this cheap energy.

This are the graphs that accompanies the tweet:

Tweet dieterjong 20200421

There was indeed a sudden loss of wind capacity somewhat before noon, correlating with a negative price and leading to positive prices again. Initially, I assumed that the twitterer was being sarcastic, mocking a sudden wind lull, but scanning through his Twitter time line suggested that this might not be the case…

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Hornsdale Power Reserve: huffing and puffing old men coming to the aid of their colleague

Now it was established in previous two posts that the Hornsdale Power Reserve did surprisingly little to avert a frequency drop caused by a 560 MW capacity loss (contrary to what was suggested in the RenewEconomy article), the focus of this post will be on how the message was brought. Knowing how little the battery actually did, then how on earth could Giles Parkinson paint it as if something extraordinary had happened? This post will explain how this is done.

Let’s start with the title:

Tesla big battery outsmarts lumbering coal units after Loy Yang trips

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Hornsdale Power Reserve: the mouse that stopped the elephant from falling

After writing previous post, the RenewEconomy article kept going through my mind. The author of the article suggested that the response of the Hornsdale Power Reserve to a tripping coal fired power unit was extraordinary, when in reality it was insignificant in the grand scheme of things. I wondered why on earth the author was so lyrical about what was in fact a poor performance…

Then it suddenly struck me. It might well be a misinterpretation of how the event was represented.

Let me explain.

There were two graphs presented in the article. The first one is the frequency versus the response of the Hornsdale Power Unit and it stood central in previous post. There is however a second graph in the article and it is this graph that could easily lend itself to misinterpretation. It shows the sharp decline of the tripped coal unit combined with the response of the Hornsdale battery:

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Hornsdale Power Reserve: “outsmarting” lumbering coal units by four seconds?

This is an update on a previous post about the claim that the Hornsdale Power Reserve (in South Australia) is helping to prevent blackouts in Melbourne (in Victoria), roughly 1,000 km away from each other. In that post, I rejected that idea, saying that this was highly unlikely because the capacity of the Hornsdale battery is way too small to do so.

In the meanwhile, I got a link to an article that seems to describe such an event. At the end of 2017, just after the Hornsdale Power Reserve was put into use, a coal fired power plant unit in the state of Victoria tripped, causing a sharp drop in frequency and that triggered the Hornsdale battery to supply power to the grid. Its response was much quicker than that of a coal fired power plant commissioned to compensate for the loss.

Melbourne was not specifically named in the article, but the question doesn’t really change much: did the Hornsdale Power Reserve in South Australia actually helps to prevent a blackout in the neighboring state of Victoria after a coal fired plant unit failed there in December 2017?

Did this article really provide some solid evidence that this happened? And if so, how did the battery manage to do so, considering its capacity is only 100 MW and can store 129 MWh?

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