Comparing solar and wind in the Netherlands with Belgium

In the post at the end of February, I compared two graphs showing the electricity production by solar and wind versus household electricity demand of the Netherlands, this for the months of June 2021 and December 2021. Belgium is a neighbor country of the Netherlands, so I wondered how electricity production by solar and wind in Belgium would compare with the Netherlands in the same period.

Both countries have around the same share of solar and wind in electricity demand, but population is different (more people in the Netherlands) and also have different installed capacities of solar and wind (much more solar capacity in the Netherlands), so that could show some interesting differences.

The Belgian solar and wind data is registered at 15 minutes intervals, but I don’ t think that this is the case for the graphs of the Netherlands. My guess is that it uses 1 hour intervals (quarter hour intervals or half hour intervals would give much more fluctuations). Combining the data of Belgium at 1 hour intervals with the digitized data from the Netherlands gives this:

Chart16b: solar and wind, Belgium vs the Netherlands

In general, both curves follow each other more or less. When there is less production in Belgium, that is also the case in the Netherlands. When there is a lot of production in Belgium, the same is happening in the Netherlands. That is to be expected, Belgium and the Netherlands are neighbor countries and weather systems are not that different over such a short distance.

What however jumps out are the huge spikes of solar (and wind) production of the Netherlands compared to Belgium in June. Both countries have very pronounced daily peaks in June, but the peaks of the Netherlands go pretty high compared to Belgium.

However, December shows a different story. Production is generally lower in December compared to June and production is also much more irregular. There are also some spikes, but they don’t rise that high and production in the Netherlands is often only slightly above the Belgian production. What is going on there?

Let’s first look at the capacity of both countries. In the BP Statistical Review of World Energy tables, I found these capacities for solar and wind for Belgium and the Netherlands (data of 2020, so 2021 maybe slightly different):

Capacity Solar (MW) Wind (MW)
Belgium 5,646 4,692
The Netherlands 10,213 6,600

The solar capacity of the Netherlands is almost double that of Belgium and this clearly shows in the June daily peaks. Solar at our latitude has a capacity factor of around 11%, but this is on average per year. Days are much longer in summer and it is less cloudy, so the capacity factor can be double the average in summer. This, together with the almost double capacity of the Netherlands, is likely driving these steep peaks in June.

Solar is much less prevalent in December in the Netherlands due to the shorter days (roughly 8 hours day light in December versus 16.5 hours day light in June) and that is not much different from Belgium in June and December. The capacity factor of solar in December is about 2%, so the December curve is mostly influenced by wind production. Solar is much more regular than wind. The sun is rising and setting every day (albeit at different times throughout the seasons), but wind is much more irregular. There can be times of prolonged wind lulls (like in the middle of the month of December) of periods of stronger wind (beginning and end of December). If solar is hardly presented in December, then it falls back to wind and this explains the more irregular production in December.

There is also a difference in onshore and offshore wind. Belgium has only slightly more onshore than offshore wind capacity. The difference is likely much bigger for the Netherlands. The offshore wind page of the Dutch Government gives a capacity of 2.5 GW in 2021, so probably somewhat less in 2020. It is not really clear what the exact capacity for onshore wind is. Contrary to the offshore page, the onshore page only gives the target capacity for 2020 (6 GW). Later on that page is mentioned that extra measures are introduced in order to meet the target in 2020, so this might indicate that their target was not reached in 2020. It is also possible that they did reach their target in 2020, but that the BP data is off. Either way, the Netherlands likely has a much bigger share of onshore than offshore. Which seems plausible, this would then give a lower capacity factor than wind in Belgium (the capacity factor of offshore wind is higher than that of onshore wind) and combined with a somewhat higher capacity, this would result in a not much higher production than Belgium.

As an aside, the different dynamics of solar and wind reminds me of a post of a couple years ago in which I tried to figure out whether it is better to increase solar capacity or to increase wind capacity. My original assumption back then was that it would be better to increase solar because its production coincides better with demand than wind. Yet that was not what the model output showed. The reason for this now becomes much clearer when comparing above graphs. Solar has a much bigger seasonal difference, therefor it will be harder to integrate it in a grid that has its highest demand in winter and lowest in summer.

Anyhow, even the combination of solar and wind will have its consequences. Those graphs learn us that the more Belgium and the Netherlands will increase their intermittent capacity, the more they will experience the same problem in the same situation (a lot of production at times of low demand and low production at high demand). The problem is that Belgium is expected to rely systemically on import during its transition in the next couple decades and dynamics will exclude the Netherlands from the countries that will be able to provide electricity when Belgium needs it the most. As a country that is going to rely heavily on import, I don’t think it is a bright idea to use the same strategy as its neighbor country (make that neighbor countries, also Germany is betting on the same strategy).


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