Tag Archives: Fallacy by omission

The Sahara or not the Sahara, that is the question

Another thing that I wanted to write about in the solar-and-wind-will-green-the desert story is the region that was modeled by the researchers. I understood from the BBC article that the researchers distinguished two regions: the Sahara and the Sahel. Which puzzled me at the time. These are two distinct regions. The Sahara is a desert, while the Sahel is a transitional zone between the Sahara Desert to the north and the more humid savanna belt to the south.

It is not very clear from the BBC article what the exact relationship is between the two in that paper. For example this statement (my emphasis):

“Our model results show that large-scale solar and wind farms in the Sahara would more than double the precipitation, especially in the Sahel, where the magnitude of rainfall increase is between 20mm and 500mm per year,” said Dr Yan Li, the lead author of the paper from the University of Illinois, US.

That is rather confusing. The title is “Large-scale wind and solar power ‘could green the Sahara'”, but this quote seems to suggest that the large-scale installation in the Sahara would have the most effect in the Sahel, which seems to contradict the title since the biggest effect is not in the Sahara, but in a nearby region of the Sahara.

Also what was found is rather confusing. I can understand the bottom value of 20 mm (probably the northern part of the Sahel/southern part of the Sahara). If a region is a desert, then a precipitation increase of 20 mm/year will not change much. Unless the precipitation is close to 250 mm/year (which is widely taken as the upper limit of being a desert). On the other part of the spectrum there is the 500 mm/year increase (probably the southern part of the Sahel). That much precipitation increase would make a desert green, but the Sahel is not really a desert.

There was however a graph in the BBC article that contained some numbers that I could use to shed some light on the issue. Let’s go back to that graph:

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Large-scale wind and solar power ‘could green the Sahara’

That is the promising headline of a BBC news article. They referred to a paper in Science from the University of Illinois. Lead author Yan Li explains that they modelled what would happen if (really) huge parts of the Sahara desert are covered by renewable energy sources. They calculated that if 9 million km2 of the Sahara is covered, then precipitation would more than double and vegetation cover fraction would increase by about 20%. It has to be of that scale, fewer panels and turbines would have a limited effect.

The researchers focused on this region because it is close to large energy markets in Europe and the Middle East (weird, the journalist forget Africa as a close-by energy market) and they add that such “a massive installation in the desert would generate four times the amount of energy that the world currently uses every year”.

The impact on humans living there would be “mostly positive”: the extra rain will improve agriculture and growth in production of livestock.

Now my head begins to spin. It solves the EU energy transition, optimizes land use, creates more precipitation therefor greening the desert & beneficial for agriculture/livestock and, in one fell swoop, it fixes the climate. Everybody wins.

Not so fast! It seems pretty straight forward to look at the Sahara as a potential energy provider able to deliver plentiful solar and wind power, but it is anything but. There are some things that the journalist is rather silent about.

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Oreskes 2004 and Peiser

As mentioned in previous post on the consensus article in skepticalscience, there was an entry explaining the Oreskes 2004 paper. In the article, it was presented as “Oreskes 2004 and Peiser”. Which was an odd thing. Peiser didn’t write the paper together with Oreskes (otherwise it would be “Oreskes and Peiser, 2004). At the contrary, Peiser wrote a critique on the conclusion of the paper (that not a single paper rejected the consensus position). The author of this article seems to have a lot of confidence also mentioning the critique together with the Oreskes paper.

At that time, I did not know much about the Peiser critique and initially had to rely on the explanation provided by the author of the skepticalscience article. This is how the critique is presented in the article:

Oreskes 2004 and Peiser

A survey of all peer-reviewed abstracts on the subject ‘global climate change’ published between 1993 and 2003 shows that not a single paper rejected the consensus position that global warming is man caused (Oreskes 2004). 75% of the papers agreed with the consensus position while 25% made no comment either way (focused on methods or paleoclimate analysis).

Benny Peiser, a climate contrarian, repeated Oreskes’ survey and claimed to have found 34 peer reviewed studies rejecting the consensus. However, an inspection of each of the 34 studies reveals most of them don’t reject the consensus at all. The remaining articles in Peiser’s list are editorials or letters, not peer-reviewed studies. Peiser has since retracted his criticism of Oreskes survey:

“Only [a] few abstracts explicitly reject or doubt the AGW (anthropogenic global warming) consensus which is why I have publicly withdrawn this point of my critique. [snip] I do not think anyone is questioning that we are in a period of global warming. Neither do I doubt that the overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact.”

A [snip] in a skepticalscience article? I need to know more about that! What exactly got snipped in that quote from Peiser?

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Just an innocent bystander?

The more I look into the story of the family that owned a Tesla powerwall (see previous four posts), the more I get the impression that there is more to the story than what meets the eye. In the article (and also the video that was linked to), it was the man of the family who did the talking. He was portrayed as a family man from Kermt (a tiny village with a population of 4.122) who installed a powerwall and this allowed him and his family to reduce their dependence on the power grid.

Yet, I was not really convinced. He looked indeed as an ordinary family man, but he sounded knowledgeable, the video was well made and only the advantages were highlighted, avoiding the disadvantages altogether. It seemed more like a slick sales pitch than an objective news item.

Later I learned that he signed in for the new model of the Tesla (the car). It is a hyped status symbol, not something that an ordinary family man would go for and he probably would have a higher than average salary.

There was also the puzzling tagline on his Facebook account:


Here you find all details on the home battery of Tom Nijsen and his strive for an inter-dependent energy landscape.

His strive for an inter-dependent energy landscape?

These are not the words that I would expect from a simple family man.

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Easily through the night on a fully loaded powerwall

This is already the third post on the Tesla powerwall series and especially how it is (mis)presented in the mainstream media. This misinformation is not only limited to the mainstream media, it is also strong in social media. The subject of this post is a facebook post by the owners of the Tesla home battery mentioned in previous two posts.

It starts informative with a description of their powerwall (translated from Dutch):

Our home battery is a lithium ion battery with a usable capacity of 6.4 kWh (slightly less than our average daily consumption). We decided NOT to go for the #offgrid option, so when the grid voltage is lost, our battery will also not be able to power us. The battery can deliver 2 kW continuous power, with a peak power of 3.3 kW.

The capacity of their powerwall is indeed somewhat lower than their average consumption. I understood from a previous post that their annual consumption is around 3,200 kWh, meaning around 8.77 kW per day. On average of course, their consumption will be lower in summer (when production is high) and in higher in winter (when production is low).

Not sure whether all this 6.4 kWh is really usable and how long it stays that way (this battery is currently brand new, but lithium ion batteries degrade after a while). But that aside.

It becomes a bit trickier in the next sentence when it comes to the limitations of the powerwall (translated from Dutch):

With a load of 2 kW, the battery is depleted after 3 hours.

Followed by the justification that this is not much of a restriction for them (translated from Dutch, my emphasis):

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The experts who forgot that wind energy is intermittent

A final post in the energy fact check series from SER. Fact check number 4 is titled “Do wind mills run mostly on subsidies?“.

This is the reasoning why subsidies are necessary according to the fact check: since the cost of wind energy is somewhere between €0.074 to €0.098/kWh for onshore wind and €0.133 en €0.157/kWh for offshore wind and on the price on the energy market is around €0.04, therefor subsidies has to be provided to settle the difference.

I have no problem with that.

The fact check starts with the costs of wind energy: cost of the wind mills, installation and maintenance. That is rather brief, but luckily there was a source at the bottom of the page for more information. Unfortunately, no link to it, just a name of a report: Final advice base costs 2014 by ECN (Energy research Centre of the Netherlands). Fortunately that report (Dutch) was easily found on the internet. Strange, why was there no link provided for a source that is readily available online?

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The (actually not so) “excellent” fact check

There was some controversy related to the third fact check of SER on energy. This fact check is titled “Nearby residents have mostly nuisance and little benefit from windmills(Dutch). Two action groups opposing wind mills read the fact check and were not amused. They claimed that the information of the fact check was not objective and incomplete.

Rightfully so. That fact check exaggerated the advantages of wind energy and minimized its disadvantages.

This is no big surprise. This kind of framing is not only done in this fact check, but also in the four other energy fact checks of SER. I would even say that this framing is endemic in alternative energy reporting. The advantages are being emphasized and the disadvantages minimized or even ignored. Being confronted with the nuisance of wind mills first hand, it was probably not that hard to notice for those two groups.

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