Tag Archives: Wind energy

Do wind and solar “complement” each other during winter?

The second fact check of the “factchecker energy” of SER is titled: Is there a future for solar energy in the Netherlands?. Although the author of this fact check admits that solar energy only has a very tiny share (0.1% of the energy consumption) and it needs to be balanced by other flexible energy sources, he is very optimistic about the future. His “fact” check seem to rely on future developments related to solar energy.

As a whole, it seems a quite bland and overly optimistic fact check, but there was one statement that caught my attention (translated from Dutch, my emphasis):

There is a factor of ten difference between summer and winter output of solar panels. What the share of solar power in the electricity mix will be, will depend to a large extent on the developments in electricity storage (for short and longer periods) and of the expansion of the electricity connections with other countries. Wind power and solar energy complement each other in that respect: the supply of wind power is higher in the winter when the supply of solar energy is lower.

That is an interesting statement. Apparently wind energy produces more power in winter and this compensates for the loss of output of solar cells during the same time. I decided to have a look at the data to find out to what extent “wind complements solar”, but also the significance of this phenomenon in a continuous working grid.

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Half News: (installed) capacity of wind energy has overtaken coal

From the half-news department comes the article titled Capacity of wind energy has overtaken coal in De Morgen (the Flemish Guardian).

Wind energy overtakes coal - De Morgen , February 9, 2017

This is how it is explained (translated from Dutch):

Last year, the installed capacity of wind power in Europe surpassed that of coal. This according to figures from the industry association WindEurope.

In terms of capacity, only gas-fired power plants preceded wind energy.

The source was an article with the same title from Belga (a news agency) and it was copied verbatim by a huge flock of news sites in Flanders.

The article in De Morgen jumped out as a sore thumb: it appeared in the section “Science”. Probably copied by a “science” journalist who had no clue that comparing installed capacity of wind with coal is meaningless and a direct comparison of the two is misleading.

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Flemish (onshore) windmills have almost the same capacity as a nuclear reactor

The journalists of our beloved Flemish media seem to go ballistic lately. Yesterday there was the item in the VTM news about the current “drought” that was “direct result of climate change”. Today the VRT news felt it had to compete with that and went full stupid in an article with the sensational title:

Flemish windmills have almost the same capacity as a nuclear reactor

vrt news 20161228 windmil

Apparently the onshore windmills in Flandres have a total capacity of 920 MW, which is only slightly below the capacity of (some of) our nuclear turbines (at somewhat above 1,000 MW).


I am afraid that I have to spoil that party…

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In search of “only” 1414 MW (if non-dispatchable power sources are dispatchable)

Last Thursday, a Flemish newspaper brought the story that “the lights will go out in 2020”. We heard that many times before in the past. This time the statement was made by Andries Gryffroy, who was called the “energy expert” of N-VA (Flemish political party on the center right). He rightfully questioned the “energy plan” of current Flemish Minister of Energy, which is solely based on extra solar and wind energy. Even with those extra windmills and solar panels, we will not be able to produce enough energy to meet our demand in a few years and could face power shortages by 2020. More, several old conventional plants will need to be decommissioned in the next years and the new solar panels and wind mills need backup. He gave the example that in winter only 3% of nameplate power of solar energy is produced, while we use most energy in winter.

Okay, I dig that. Solar and wind provide less energy in the winter when we need most energy. Just adding more intermittent energy sources without backup and additionally decommissioning older conventional power plants, makes a good recipe for energy shortages. Especially in winter at peak demand. Especially with our aging power plants. Our politicians are talking about energy security for years now, but in the end go for extra windmills and solar panels. Probably to meet the EU goals.

Although I agree with what was being said, there were some things that seemed rather odd. For example, it was calculated that in winter we will have a shortage of 1,414 MWh and explained that this is the equivalent of 1.5 Belgian nuclear power plants. Which doesn’t make much sense. 1,414 MWh is the electricity that 1.5 nuclear power plants will produce in one hour. My guess was he was confused between “megawatt” (power) and “megawatt hours” (energy). Or was it the journalist that brought in the confusion?

Also the calculated number was puzzling. At first glance, it seems rather unrealistic. Apparently, we would be able to decommission older gas power plants PLUS arrange backup for a doubling of our capacity of intermittent energy sources, yet only need 1.5 conventional power plant to compensate for all that!?

Luckily, the paper version of the news paper mentioned how the calculation was actually done:

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Creative accounting with wind energy

As seen in last post, it is deceitful to use the metric of “household equivalents” when talking about an intermittent energy source injected in a continuous working grid. It is one thing that journalists do this, but producers of wind power should know better, right? Then think again. The very first post on this blog, back in february 2013, was about such a claim made by a wind energy producer, C-power. They went even furter than this in their environmental impact page in which they paint an incredibly rosy picture of wind energy. It all starts with the “it is good for our (grand)children” meme:

“With our 325,2 MW offshore wind farm, we contribute to delivering a cleaner and safer environment to our children and grandchildren”, says CEO Jaak Rutten.

Throughout the years I have learned this to be a red flag. They continue:

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is very positive. Wind power consumes no fuel, and emits no air pollution. Wind power does not generate any toxic waste nor does it constitute a major safety risk.
The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months.

C-Power will, with its expected yearly production of 1 TWh, avoid every year 415,000 tonnes CO2, which represents:

  • the annual CO2 absorption of a forested area of 65.000 ha
  • 1/3 of the forest area within the Flemish Region

The story they paint is so skewed that I don’t really know where to start here.

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The misleading measure of “household equivalents”

In last post there was a statement from a documentary maker about wind turbines that:

… each one [is] capable of powering 2000 households” …

Such statements are common in the media when alternative energy is concerned. For a country like Denmark I think this could somehow work, but other countries don’t have for example a couple of bigger neighbors that are able to absorb their overproduction or readily provide power when there is a shortage on their grid. Yet, also in Belgium this statement is used plentiful and, according to me, unwarranted.

The problem with this statement is that it has no relation whatsoever with reality. None of those households can actually rely on the supply of one or even more turbines. Those households get the average of the energy produced by it. In a way, one could say that over one year the turbine produces as much energy as the average yearly demand of those households.

What is not to like?

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Wind, a free source of energy and other one-sided information

danish windmills

A couple days ago I watched the Discovery Channel program “Incredible Engineering Blunders”, the episode that looked at the problem which the early Denmark offshore windmill suffer from. To summarize: the foundations of the early windmills were build on a monopile foundation, but because a windmill is very top-heavy, there are huge strains on the joints. If the grout in that connection cracks or grinds away, the windmill could sink down on the base pipe. Although there are stoppers in place that initially prevent this from happening, these were not designed to take the full load of the turbines on a permanent basis. If they crack under the pressure, the turbines could collapse into the sea.

But that was not the thing that got my interest. It was the typical way in which wind energy was described (my emphasis):

[…] I am heading out in the freezing North Sea to help to fix a blunder that threatens the lights switch off in Denmark. […]

[…] The wind that is churning up these waves and my stomach, is a free source of energy that is helping to meet Europe’s increasing power demands. […]

[…] On this site alone there are 80 turbines. Each one capable of powering 2000 households. This is a booming industry and it really is the future of power generation. […]

[…] Europe’s off shore wind turbines create a clean, unlimited power. […]

[…] They also work in deeper water, opening up more potential sites out at sea. That means cheaper, more abundant, clean power for everyone. […]

Basically, this is exactly the same what the media is tells us: wind energy is free, clean, unlimited, it can power x number of households, it already has an important share and it is the future of energy production. These are not exactly lies, but it is only part of the truth.

It threatens the light switch off

It seems to have such an important share that it threatens the lights to switch off in Denmark. That is a bit over the top. While Danish wind mills produce on average 34% of the electricity supply, that is on average. Wind energy, being intermittent, it has sometimes a higher share (and then this fact is hyped all over the media) and sometimes has a smaller share (not reported in the media). I think their negative effect on the reliability of the grid is threatening much more the lights switching off than when their share would be declining for whatever reason.

How much less than average? Well, a lot less. When downloading the Denmark wind data from 2015, the minimum production was 1.1 MWh on October 4, 2015 at 08:00 (0.023% of the installed capacity)! The total load at that time was 3008 MWh. So something was able to take over to compensate for the other 3006.9 MWh that hour. That day the production was really low, a meager 634 kWh for the full day (about 0.5% of the installed capacity). Total load was 78625 MWh. So something took over for the 77991 MWh that day. Anybody heard about that in the media?

If the other sources could compensate for such a huge dip in production, then some windmills that stop working because of foundation problems would very unlikely threaten lights to switch off…

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