I noticed something recently that I can’t find an clear explanation for, so I’m posting it here to help understand what’s going on.
In the European Union, there is a sort of law called the Energy Efficiency Directive, which I’ve written about before, and this relevant when we think about data centres and decarbonising the supply of energy they require.
Earlier this year a report was published by the European Commission, which covered loads of information about the sustainability of data centres in Europe, and at the back they listed a table of reported energy use by data centres in all of the member states of the European Union.
Here’s the screenshot of the specific page that caught my eye.
What am I looking at? Why does this matter?
look at the central column where I’ve highlighted something in yellow. This is reporting the total energy consumption for all the data centres in Germany in the year of 2024. It’s about 4608.53 GWh or if you prefer, about 4.6 TWh.
By itself, this seems like a colossal amount of energy, but after getting familiar with these numbers for some research at work, these numbers seem way too small!
Why is this too small?
In December of 2024, the German Ministry of Economy and Climate (the BMWK), published to study which estimated that in 2024 there was probably something like 20 TWh hours of energy consumption by data centres. This is around four times larger!
I’m much more willing to believe the 20TWh figure because it was carried out by a number of domain experts from different organisations who had a chance to review each other’s work, where is the reported figure is what datacentre operators could be bothered to report.
Where is the other 15TWh of energy?
This begs the question, once we see such a huge difference, of why we see such a huge difference.
We also know, that among the countries in the European Union, Germany after a slow start had, relatively speaking, pretty high uptake in terms of reporting. At least 70% of the data centres that were big enough to report did report. That leaves around 20 to 30% of all data centres that haven’t shared any information, even though the law it’s pretty clear that they have to, even if they do not choose to make this information available for the world to see.
What this looks like.
If the disclosed energy usage was less than 5TWh for Germany, when maybe 60-70% of the datacentres were supposed to have reported, actually did, and the BMWK estimates are more like 20TWh, I think that suggests the biggest consumers (i.e the ones in that missing 30%) are not reporting.