Last Monday, our Prime Minister gave a speech on the occasion of the Belgian Diplomatic Days (Dutch ahead). In his speech, he claimed that a lot has been achieved by the current Government and, as an example, he made the remarkable claim that the Belgian wind farms in the North Sea produce the same as four nuclear power plants! He raised four fingers and said “four” twice, so he apparently wanted to make a point with this specific claim.

Initially, I was not sure what he actually meant. He used the term “produced capacities” (translated from Dutch). So what did he mean: production (MWh) or capacity (MW)?

My first guess was that he was talking about “capacity”. That doesn’t add up however: the current capacity of Belgian offshore wind is 1,178 MW according to Elia (Belgian transmission system operator).

That is a tad more than the capacity of a large Belgian nuclear reactor of roughly 1,000 MW (from 962 to 1,048 MW). So, when it comes to capacity, that is not four reactors, in fact it is only one.

Maybe he didn’t mean large reactors, but small ones? Belgium also has smaller reactors of 433 MW. But that would still be somewhat less than three reactors, not the four he claimed.

It couldn’t be production either. The capacity factor of offshore wind is almost 40% (it was 37% in 2018). The capacity factor of a good working nuclear reactor could exceed 80%, so it is roughly double that of offshore wind. That is just the production of a small nuclear power plant or only half the production of a large one. Definitely not four.

Then maybe he also included the planned capacity? But then no, he clearly made the claim in the present tense, not the future tense. It wouldn’t match what he was saying: the point of his speech was that the current Government achieved a lot already. Also, there is some planned capacity in the pipeline, but not thát much.

I realized after a while that I might be looking in the wrong direction. He is most likely just confusing capacity with production. I think that this is the (faulty) reasoning:

1. Turbines with a total capacity of 1,187 MW can theoretically produce 10,400 GWh per year at maximum capacity. Remember 10,400.
2. Offshore wind however has a capacity factor of a tad below 40%, so average production will be: 10,400 x 0.4 = 4,160.
3. If you now divide 4,160 by the capacity of a large nuclear reactor, the result is four…

And, hey pronto, here is your proof that our Belgian offshore wind produces as much as four nuclear power reactors. Unfortunately it is production, not capacity, that we were counting, so the conclusion is wrong.

If you confuse between capacity and production, then it is very tempting to come to this (wrong) conclusion, especially when you need success stories to justify the own (meager) energy policies. With the added pressure of several climate marches in the streets of Brussels and elections just around the corner.

Concluding, does Belgian offshore wind produces as much energy as four nuclear reactors? Well, not exactly and that is not very hard to understand: it is mathematically impossible to come to the conclusion that offshore wind produces the same amount of electricity as four nuclear reactors when we know that Belgian offshore wind has the capacity of only one reactor and has a capacity factor of roughly half that of a nuclear reactor…