Author Archives: trustyetverify

A “skewed” distribution: synchronizing intermittency

According to some of our politicians (among them our federal Minister of Energy) we are missing out on cheap electricity from solar and wind. They look forward to abundant electricity from abroad, specifically from Germany, and to be able to import this cheap electricity.

We surely will get dependent on imported electricity soon. Belgium is going to decommission 6 GW of nuclear capacity (currently producing roughly half of our demand) by 2025 and replace it with 2.3 GW of gas fired power plants plus increasing solar and wind capacity. It is expected that Belgium will get structurally dependent on import for about 25 to 30% of its demand (and likely a whole lot more by 2050).

As I wrote several times before, I have my doubts whether that import will be cheap and my suspicion has to do with the time when this cheap electricity is produced. I think that the three dates explored in previous post can shed some light on why the prices of imported electricity from Germany will not be cheap. Let’s just look what prices did during those three days.

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A “skewed” distribution: interconnecting intermittency

While creating the graph that I used in previous post, I noticed something that I expected for a long time. Remember, my graph was a recreation of this graph showing the sorted daily contribution of solar and wind in the Netherlands:

Sorted contribution of solar and wind of the Netherlands

It shows that the lowest daily production of solar and wind between January 1 and November 16 was measured on November 16. When I was creating my graph depicting the Belgian sorted daily contribution, I found that the lowest production of solar and wind in Belgium over the same period was also November 16. That should not have come as a surprise, Belgium and the Netherlands are neighboring countries.

That November 16 date was not the only date that appeared in that original graph. Besides November 16 (lowest production) there are also July 29 (highest production) and August 2 (in between). That made me wonder whether those two other days match as well and to what extent this is also true in other neighboring countries. I have some data from solar and wind in Germany, so I will also include Germany into this comparison. Let’s dive right in.

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A “skewed” distribution: the volatility of solar and wind

This tweet sums up the biggest problem with intermittent power sources:

Yesterday, a fairly dramatic low in terms of solar & wind output. Fortunately, there were also great days this year.
Although sun and wind often complement each other, the total forms a rather ‘skewed’ distribution. We will have to learn to deal with that soon.

Tweet WM_visser 2021-11-17

This is the graph he is talking about:

Sorted contribution of solar wind (The Netherlands)

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The fossil-fuel subsidies blind spot

Belgium apparently signed the declaration to end “fossil fuel financing”:

Tweet John Murton 2021-11-12

The guy on the left is John Murton (UK Envoy to COP26) who is thanking Zakia Khattabi sitting on the left (Belgian Minister of Climate, Environment, Sustainable Development & Green Deal from Ecolo, the French-speaking Green Party of Belgium) for joining the declaration. The inconvenient reality is that the Belgian Federal Government very recently approved subsidizing the building of new gas-fired power plants in order to replace nuclear power plants.

Most comments below the tweet highlighted the hypocritical nature of that signature, rightfully so. John Murton tried to defuse the situation by responding that he actually meant “international financing” or “overseas financing”, but nobody was particularly impressed by that intervention, also rightfully so. It is still hypocritical to pledge to end international/overseas fossil-fuel financing while at the same time subsidizing the fossil-fuel industry nationally.

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Pumped hydro more expensive than batteries: a tongue-in-cheek analogy

Having written the last five posts on the comparison between hydro and batteries based on the calculations in the SolarQuotes article Snowy Hydro 2.0: More Expensive Than Battery Storage, I think it is time to conclude this series. In previous posts, I focused primarily on the errors and had split up the series into several posts. This allowed me to discover the different aspects in more depth, but re-reading those posts, I had the impression that the technique that was used to favor the batteries over hydro now might not really that clear anymore. It might also not be very clear how absurd the comparison between average output versus maximum capacity actually is.

I try to remedy this by illustrating those techniques in a tongue-in-cheek example in which I will make the same flawed calculations as done in SolarQuotes article and making equally nonsensical arguments. If you want to appreciate this post and you didn’t read previous posts yet detailing the (flawed) arguments that were made in that article, then it might be advised to do that first or read the SolarQuotes article. Otherwise you might not understand the gist of this post.

To illustrate this technique, I will tell a story of a transport company and its CEO who wants to buy a new delivery van for long-haul transport. He is in favor of a big van that he thinks is suitable for handling the bigger loads that the van is expected to handle.

Now assume that I am an employee of that company and that I am assigned to prepare the dossier. However, I don’t like the bigger van and I am in favor of a much smaller van that unfortunately is less suitable for larger loads. The task before me is to convince my boss that the smaller delivery van is nevertheless the better choice…

That seems pretty impossible to do, but after having written already five posts on the argumentation of batteries versus hydro, I think that I now have sufficient insights to successfully finish this difficult job. Trust me, this is going to be a breeze…

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Pumped hydro more expensive than batteries: apples-to-apples

A lot of effort in the article in SolarQuotes (that is the subject of the series that starts here) went into avoiding a direct, apples-to-apples comparison between hydro and batteries. That made me wonder what the result of such a comparison would be.

Let’s just jump in. This is what we are working with:

  Snowy Hydro 2.0 Hornsdale battery Victorian Big Battery
Capacity (MW) 2,000 100 300
Storage (MWh) 40,000+ 129 450
Price (million AU$) 10,000 89 180

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Pumped hydro more expensive than batteries: battery replacement(s)

Even when accepting the flawed calculations of Ronald Brakels, it provided only a fragile win for the battery scenario. This prompted him to start a new calculation in order to justify the battery/solar setup. It involves a battery system that is currently being built: the Victorian Big Battery. His reasoning is that battery prices drop rapidly and he also proposes a way to set aside some the initial investment in order to replace the battery at the end of its economical life.

Let’s just jump right in. This is the information he gathered about the Victorian Big Battery:

  • Capacity: 300 MW
  • Storage capacity: 450 MWh
  • Price: AU$180,000,000
    (again no justification for this price tag, just his hunch)

Then he repeats the flawed calculation by calculate the price:

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Pumped hydro more expensive than batteries: why the winner is unclear

Previous post ended with the conclusion of Brakels’ article that the “winner is unclear”. That is quite a surprising conclusion of an article praising the strengths of the batteries while downplaying the weaknesses. These are the two reasons why Brakels thinks that the winner is unclear (my emphasis):

But because Snowy Hydro 2 may come in at less than the $10 billion or so I expect and because I can’t be certain the additional return from the battery setup will be enough to replace them when they fail, I can’t pick a winner.

The second argument is the most interesting. That statement looks rather cryptic and the meaning depends on the definition of the words “return” and “fail”.

“Return” could mean financial return and “fail” could mean end of economical life (additional financial return of the battery/solar scenario is not enough to replace the installation after its economical life). I will explore this meaning in the following post.

“Return” could also just mean output and “fail” could mean when the additional output of the battery/solar scenario is insufficient (additional output of the setup is not enough to fill in demand and then there would nothing to replace it with). If that is what he means, then he is rightfully pointing to the fatal flaw in his calculation:

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Pumped hydro more expensive than batteries: the calculations

Now let’s take a look into the calculations that Ronald Brakels made to prove that hydro power (Snowy Hydro 2.0) is more expensive than battery storage (Hornsdale Power Reserve). His arguments were spread over many paragraphs and at first glance it was not very clear what he was calculating exactly and why. Therefor, I thought it might be a good idea to redo his calculations. This reconstruction will be the subject of this post and I will clearly write out all his calculations in order to better understand his arguments.

The calculation can be divided into three parts.

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Pumped hydro more expensive than batteries: the intro

At the end of last week, I came across a SolarQuotes article about Snowy Hydro 2.0 being more expensive than batteries. Snowy Hydro 2.0 is a pumped hydro project in Australia (New South Wales and Victoria) and is currently under construction. The brunt of the article is that pumped hydro is too expensive compared to (grid sized) batteries and the plea is made to halt the project in favor of batteries.

That was new to me. As far as I know, pumped hydro is the cheapest way of dispatchable backup in order to counter intermittency and definitely cheaper than batteries. Yet, the author of this article argues that it is the exact opposite.

The name of the author of the article, Ronald Brakels, rings a bell. Not even a year ago, I wrote a post on his claim that South Australia has the second cheapest electricity in Australia, despite it having the most expensive electricity. He did this by applying two neat tricks, sneakingly morphing South Australia from by far the most expensive to the “second cheapest”.

With that in the back of my mind, I expected some trick(s) to be performed in this one too.

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