“Electricity prices” decrease the more sun and wind there is in the mix

Are solar and wind the cheapest? That seems to be the suggestion in this this tweet (translation from Dutch, my emphasis):

Time and time again, it appears that electricity prices decrease the more sun & wind there is in the mix.
Likewise, all trend lines will reach ZERO once the share of solar & wind approaches 100%.
January 2023 is no exception.
#graphoftheday

Ah, that elusive electricity-prices-go-down-when-the-share-of-solar-and-wind-increases narrative again. As expected, there were several commenters singing the praise of the cheapness of solar and wind energy. But then, what does he mean by “reach zero once the share of solar and wind approaches 100%”? And what exactly are those “electricity prices” that he is talking about?

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Offshore wind with a capacity of “3.5 nuclear power plants”

In her interview in the Flemish newspaper (subject of previous two posts), our Minister of Energy not only said that the wind always blows somewhere in Europe, and especially at sea, but she also made following remark about Belgian offshore wind (translated from Dutch, my emphasis):

When I became minister, I hoped that our new offshore wind farm would be operational by 2027. It has a capacity of 3.5 nuclear power plants and can supply all Belgian households with electricity.

I heard members of the current Federal Government draw (variations on) this analogy between offshore wind and nuclear power plants quite a lot lately, especially (and unsurprisingly) by members of the Flemish Green party.

For the record, there is a core of truth in this statement. It is true that the capacity of offshore wind in Belgium is expected to be 3500 MW in 2027 and since most Belgian nuclear power reactors (not “plants”) have a capacity of about 1000 MW, the capacity of offshore wind will equal the capacity of 3.5 nuclear power reactors by 2027. That is where the similarities end.

The wind always blows somewhere in Europe

As seen in previous post, Belgium experienced a dunkelflaute (a period of low solar and wind power production) on November 29 and, depending on one’s definition of dunkelflaute, it may even be longer. Belgian politicians envision a situation in which Belgium relies more on import of electricity, so I wonder what those neighboring countries did during this event and whether they would be able to help us in such a situation. My expectation (based on previous posts like here, here, here and here), is that they all went through the same or at least a similar event.

Let’s start with what happened in Belgium from November 28 until December 2:

Dunkelflautes last just a few hours (oops, days)

There was a dunkelflaute at the end of last month. “Dunkelflaute” is a German word, mostly translated as “dark doldrum”. It is a period in which there is no(t much) sunlight and no(t much) wind, resulting in very low electricity production from solar panels and windmills. The media told us that Monday November 29 was such a day.

This is what solar and wind did compared to total load:

Solar and wind indeed did not do well on that day. Electricity production by solar and wind was mostly hugging the x-axis for most of the day. The combined average capacity factor for solar and wind was a measly 1.53% (between 0.06% and 7.89%). It was particularly wind that did poorly. Luckily there was some sun to elevate the capacity factor, but even that was pretty limited because days are short at this time of the year at our latitude.

A capacity of 3.5 nuclear power plants produced at sea by wind energy

The Ventilus project is a future 380 kV high-voltage power line with a capacity of 6 GW that will connect the Belgian coast with the rest of the country and will also serve as a (second) interconnection with the UK. There is quite some protest against it. It was planned as an overhead power line, but people living along the trajectory want the cables below ground. To my surprise, the Green party wants them above ground and demands a quick approval of the project by the Flemish Government. This is how Jeremie Vaneeckhout (the Flemish green party co-chairman) explains the urgency of the project (transcription translated from Dutch, my emphasis)

Ventilus is not only the project that can ensure that a capacity of 3.5 nuclear power plants produced at sea by wind energy, that we get that on land. It is also the guarantee that the vehicle fleet can be made electric, can be electrified, and that our grid will not fail, that all West Flemish companies can certainly remain on the grid.

The first time that I heard this, it didn’t make much sense to me. Our largest nuclear reactors have a capacity of 1 GW, but offshore wind currently has a capacity of 2.2 GW, so he is likely talking about a future capacity (but then (much) less than the 8 GW that the Minister of the North Sea envisioned). Where does this 3.5 GW number comes from? My guess was that it is the future capacity of offshore wind by the time that Ventilus will come into use. I found dates between 2027 and 2030, but Belgian offshore wind should already exceed 3.5 GW by then.

There also were others that started to use that the Ventilus-is-3.5-nuclear-reactors claim around the same time relating to Ventilus. The chairman of the Flemish socialist party said the following in an interview on Flemish television news one week earlier (translated from Dutch, my emphasis):

Claim: 8 GW offshore wind capacity corresponds to 8 nuclear reactors

A couple months ago, I wrote about the claim of our Minister of Energy that 1 GW of renewable capacity equals 1 large nuclear power plant (she obviously meant “reactors”). I recently came across a variation on this claim made by another member of our Government, the Minister of the North Sea (at least the stretch of the North Sea that belongs to Belgium). Here is what he said about the future plans for wind power in the North Sea as reported by a journalist of a Flemish newspaper (translated from Dutch, my emphasis):

According to Van Quickenborne (Minister of the North Sea), it is even possible to reach 8 gigawatts with a third wind farm by 2040. “This capacity is enormous, it would correspond to 8 nuclear reactors,” says the Open VLD politician, who believes this is enough to supply all Belgian families.

This seems impressive at first glance. Basically, the total capacity of wind mills on the Belgian part of the North Sea is expected to amount to 8 GW by 2040, which the Minister then compares to the capacity of 8 nuclear reactors.

There is a core of truth in this claim (our largest nuclear reactors have a capacity of 1 GW each, so 8 GW would correspond to 8 of those), but it is pretty misleading. It is comparing two different types of electricity generation having a (radically) different output.

Electricity price briefly below zero thanks to sun and wind!?

There was a high production of electricity from solar and wind previous weekend (weekend of April 23-24). As expected, there was the usual cheering and celebrating of this event. One of the many was this tweet from a member of the Flemish Green party (translated from Dutch)

Still need arguments for the roll-out of renewable energy?

Electricity price briefly below zero thanks to sun and wind

He links to a newspaper article with the same title and brings forward these negative prices as a decisive argument for more solar and wind: if you weren’t convinced yet, then this surely is the argument that will.

I don’t really agree with that. Those negative prices over the previous weekend are not an argument for the roll-out of solar and wind (maybe even the contrary) and it shows his poor understanding of why exactly electricity prices dipped below zero in that weekend.

What when the sun doesn’t shine and the the wind doesn’t blow: batteries!?

The big question was asked again. Remember, a few posts ago, our Minister of Energy tried to answer the question “What happens when the wind doesn’t blow?”, a question she apparently got asked a lot. Back then she managed to evade answering that question.

The question came back in an interview (Dutch ahead) about the energy transitions she gave to a news magazine from Brussels. Initially, it seemed we would not get an answer (the interview was interrupted at the exact moment when the question was asked), but fortunately the reporter was persistent enough to ask the question again later in the interview (translated from Dutch, my emphasis):

Wind from Denmark to the rescue?

One of the solutions that our Minister of Energy proposes for the energy transition is interconnectivity. In the webinar she gave at the end of 2020 (see previous post) she was pleased that Belgium got connected to the German grid and therefor could start to take advantage of the electricity produced by solar and wind in Germany. I am less optimistic about that. As I found in some previous posts like for example here, here and here, Belgium and Germany are neighbor countries and therefor have similar patterns of solar and wind production.

That doesn’t necessarily mean that no gains could be made by this interconnection. There will be times when Belgium could use the solar/wind overproduction of Germany, but when Germany has a excellent intermittent production, then generally Belgium does too. The same when Germany has only little intermittent production, then Belgium generally experience the same. The more intermittent capacity build in the two countries, the less Belgium will be able to take advantage of excess electricity production from intermittent energy sources.

This is however not the only interconnection that our Minister of Energy wants. A year after the webinar, she signed a memorandum of understanding (Dutch ahead) with Denmark to look into the possibility of a submarine power cable connecting Denmark with Belgium. That made me wonder whether this submarine cable would make it possible for Belgium to take advantage of Denmark’s excess intermittent electricity production and that is what I will look into this post.

What happens when the wind doesn’t blow?

Can’t get enough of the unthinking claims of our Minister of Energy. In my search for more information on the nuclear exit, I came across a webinar that she presented at the end of 2020 in which she explained her vision on this nuclear exit and the energy transition needed to accommodate this exit. She explained that a diverse set of solutions is needed, among which interconnectivity, gas-fired power plants and storage like batteries. She then continues (at 33:45 in the webinar, translated from Dutch, my emphasis):

And at the same time, we are also going to need baseload capacity, so energy sources that are running well and offshore wind really has a potential for that.

Those two statements took me by surprise. Green politicians generally don’t like the idea of baseload. The concept of baseload comes from conventional grids in which some power plants generate power at a fairly constant rate over an extended period of time, meeting minimum demand. With that definition, offshore wind obviously doesn’t have much potential for being baseload.

That she believes that “baseload is needed” is surprising at first, but notice that she redefines the term. According to her, baseload just means power sources that “run well” and then intermittent power sources can obviously also be considered baseload. They just have to “run well” (whatever that might mean).

Okay, just look at what this offshore wind “baseload” did the past two weeks (from when I started writing this post):