Tag Archives: Wind energy

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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Record hunting continues: a contribution of … 85%!

Hopefully it is not getting boring by now, this is another post on the meaningless metric of contribution of solar and wind. For those who have had enough of it, some reassurance, it will probably be the last on this subject and I will keep it as short as possible.

In this post, I am going to mine for an inconvenient example again. There are other energy sources in Belgium than solar and wind. The most interesting is nuclear. Half of our electricity comes is produced by nuclear power plants. If we do the same as solar and wind (look for record contribution), then this might get us some interesting numbers. Since total load varies throughout the day/the week/the seasons, we are bound to to find some high numbers, maybe even really high numbers.

And yes, when I calculated the contribution of nuclear in the period September 2017 – July 2018, the record value was …

… wait for it …

85%!

Eighty five percent? Where were the Minister and Elia on September 11, 2017? I also didn’t hear anything on the news either. If we have to cheer for the 45% contribution of solar PLUS wind, why was there not a peep about a 85% contribution of nuclear, all on its own?

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A new record: 0.016% contribution of solar and wind to total load!

Can’t get enough of the (meaningless) metric of record contribution of solar and wind to total load. This time, I will go hunting for another such record myself, using the exact same data that leads to that cheered record.

Remember from previous posts that the claim was made that Belgian solar and wind contributed 45% of total load on July 28 and that it was brought as something significant. Also remember that July 28, 2018 is a Saturday and that there was coincidentally a lot of solar PV and wind energy production, leading to a big contribution of solar and wind to total load. When it comes to intermittent power sources, that record is basically meaningless.

There was also this graph from Elia (our network manager) that showed other similar records of the last 11 months (see also this post):

As I explained in my first post on the subject, it suggests a steady increase. Until you realize that these are spot counts of coincidental high values, it is no less than cherry picking.

But if our Minister (and the network manager) are allowed to cherry pick, so am I! Solar and wind are intermittent energy sources and the record values are directly related to the failure to follow demand by those sources. Therefor, if there are records of maximum contribution (low demand at times of high production), then there are also records of MINIMUM contribution (huge demand at times of low production).

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Solar and wind: some suggestions on how to inflate the numbers

The previous post focused on the contribution-of-solar-and-wind-to-total-load metric as used by our Flemish Minister of Energy. In short, there was a lot of electricity production by solar and wind on a Saturday afternoon (when electricity consumption is traditionally low) leading to a 45% contribution by those two power sources to total load. This was praised as a “new record”. We can’t control the sun nor the wind and consumption of electricity follows certain patterns, so some pretty high contribution values are bound to happen, making it a rather meaningless metric.

He also used other equally meaningless metrics in te past. At the beginning of the year, he surprised us all with the MWh-per-km2 metric. According to this metric the Belgians are among the best in “Europe” when it comes to solar and wind energy! We are in the top 3 when it comes to production of solar energy per km2 and in the top 4 when it comes to production of wind energy per km2.
The problem with this metric is that it is mining for small countries with a high population density like, well, Belgium. If one want to classify countries by their population density, then this is most definitely a wonderful metric, but that is probably not what he was trying to do.

Although these two claims are as brilliant as they are meaningless, I think there are many more meaningless claims that the Minister has neglected. I want to play advocate of the devil and help him a little bit in his communication on solar and wind. In this post I will propose some other utterly meaningless claims that can be used to deceive the public in order to promote solar and wind.

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Yet another meaningless metric: contribution of solar and wind to total load

“A new record for solar and wind”. This is stated in a tweet by our Flemish Minister of Energy:

The hashtag “stroomversnelling” (the Dutch word for “rapids” and used in expressions it roughly means “speeding up” or “moving faster”) and he often uses it in relation to his policies. So, do I understand it correctly that he connects the current policies are the reason that this record was broken?

That “new record” was solar and wind producing 45% of the Belgian electricity load on Saturday July 28 at 15:00. My first reaction was: “So what?”. It probably would boil down to a few minutes in the weekend. The Minister has a history of unnuanced and misleading tweets, so I thought it would be a good idea to check what that record is all about. I turns out that this record was even less significant than I expected.

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When the relevant data doesn’t fit the narrative, just use other data that will and suggest that the relevant data fits even better

A graph that caught my attention in the “100% renewable electricity in Australia” paper by Blakers and Stocks was this one:

It shows growth of the installed capacity of solar PV and wind compared with other energy sources between 2014 and 2016. The remarkable increase of solar energy stood out, it almost doubled in three years time. Wind energy did not do bad either, the increase grew in 2015, dropped a bit in 2016, but nevertheless stayed above the 2014 value.

There is something weird about this graph: there is also an entry “nuclear” and, as far as I know, Australia doesn’t have any nuclear power plants. So this is obviously not the Australian situation.

The relevance of the graph was explained in the paper as (my emphasis):

PV and wind constitute half of the world‘s new generation capacity installed in 2014-16 (Fig. 1). In recent years, these sources provided nearly all new generation capacity installed in Australia.

That PV and wind constitute half of the new generation capacity is rather meaningless since they are comparing intermittent energy sources with dispatchable energy sources. But let’s assume, for the sake of the argument, that this comparison is somehow meaningful. What they apparently want to say is that the installed capacity of solar PV and wind did very well compared to other power sources worldwide (which explains the “nuclear” entry) and that solar PV and wind in Australia were responsible for nearly all of the growth. Therefor suggesting that there is a similar increase for Australia, only much better since solar PV and wind provided most of the new installations there.

The big question then is: why don’t they just use the Australian data to illustrate their case? The subject of the paper is renewables in Australia, yet they illustrate their claim with renewables in the world. More, since Australian solar PV and wind were almost the only generation capacity that increased between 2014 and 2016, the Australian situation should in theory be a much better illustration of what they want to prove.

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100% renewable electricity at “low cost”: the more costs are not accounted for, the “cheaper” it will get

It is not unusual in alternative energy communication to ignore or minimize its negative sides. This is no different in the Conversation article on solar PV and wind being on track of replacing fossil-fuels within two decades as discussed in the last two posts. Halfway the article there is the only admission that there might be a negative side to solar PV and wind energy:

A renewable grid
PV and wind are often described as “intermittent” energy sources.

When I read this the first time, I had high hopes that real issues would be tackled. That hope was in vein, it was followed by this sentence in full cheering mode:

But stabilising the grid is relatively straightforward, with the help of storage and high-voltage interconnectors to smooth out local weather effects.

Relatively straightforward?!?!

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