Belgian offshore wind with a capacity of „3.5 nuclear power plants“

From Trust, yet verify

In her interview in the Flemish newspaper (subject of previous two posts), our Minister of Energy not only said that the wind always blows somewhere in Europe, and especially at sea, but she also made following remark about Belgian offshore wind (translated from Dutch, my emphasis):

When I became minister, I hoped that our new offshore wind farm would be operational by 2027. It has a capacity of 3.5 nuclear power plants and can supply all Belgian households with electricity.

I heard members of the current Federal Government draw (variations on) this analogy between offshore wind and nuclear power plants quite a lot lately, especially (and unsurprisingly) by members of the Flemish Green party.

For the record, there is a core of truth in this statement. It is true that the capacity of offshore wind in Belgium is expected to be 3500 MW in 2027 and since most Belgian nuclear power reactors (not “plants”) have a capacity of about 1000 MW, the capacity of offshore wind will equal the capacity of 3.5 nuclear power reactors by 2027. That is where the similarities end.

It is however a very misleading claim for (at least) three reasons. Firstly, the capacity factors of offshore wind and nuclear are vastly different. The capacity factor of offshore wind is somewhat below 40% and that of nuclear around 90%, so that capacity of “3.5 nuclear power plants” will only produce less than half of what 3.5 actual nuclear reactors would produce.

Secondly, the output of nuclear is steady over time while the output of wind is intermittent and depending on what the wind does at that moment. Electricity production from (offshore) wind can be next to nothing at one time and going to full force somewhat later.

Thirdly, this argument is mostly used to show that Belgium can do with less or even without nuclear power thanks to offshore wind. Those who don’t know the different capacity factors of both power sources will understand from this analogy that those offshore windmills are able to replace 3.5 nuclear power reactors. That is not even close to true.

The Greens have been pointed to deceptive nature of this argument so many times by now, so I am not sure whether they genuinely still aren’t aware of this or whether they just choose to ignore it.

That made me wonder what this capacity of “3.5 nuclear power plant at sea” actually would have done during the dunkelflaute. This is the output of offshore wind from November 28 until December 2 compared to this output normalized to 3500 MW:

The installed capacity at the end of 2022 is 2787 MW, so Belgium is currently very close to the expected capacity expected in 2027 and it would not have made much of a difference from November 28 until December 1.

Now let’s crank it up a bit. The expected maximum capacity of offshore wind in Belgium is 8000 MW, so let’s see what the potential output of 8000 MW offshore capacity would have been:

This assuming that there is a linear relationship between capacity and output (which might not be the case here because this 8000 MW capacity will get crammed in a relative small area and this could impact the efficiency of those windmills in a negative way).

Anyhow, even with the same efficiency, that 8000 MW capacity is doing not much better than the 3500 MW capacity in the first 4 days, especially on November 29. On that day, there was single-digit output (on an installed capacity of 2787 MW!) during one fifth of the day and only double-digit output for the rest of the day. Doubling or even tripling those low numbers would still give low numbers. Normalized to 8000 MW, only 1 quarter hour of November 29 would have seen triple-digit output.

Let’s hope that the wind in other places in Europe will blow or that the Minister brings a shitload of batteries online, because this capacity of 3.5 (or even 8) nuclear power plants at sea will not make much of a difference during a dunkelflaute.