Inside the hall where the model runs.
A data centre is a shed full of electricity bills. Four problems, stacked, and the building is really just the cooling.

A data centre looks like a warehouse. It behaves like a power station that happens to own some computers.

Then it all turns into heat
Computers do not consume electricity so much as pass it through and hand it back as warmth. Near enough every watt that goes in comes straight back out.

That is why the cooling plant is not an accessory bolted to the side. At this scale it substantially is the building, and it is why these sites argue with local councils about water.
The expensive part is keeping it busy
An idle accelerator still costs what it cost. The bill is set by how much of the time the silicon is actually working, which is an operations problem dressed up as an engineering one.
And the network nobody mentions
Thousands of chips training one model have to talk constantly. Get that wrong and you have bought thirty thousand homes' worth of electricity to run something at half speed.
Why it matters to you
Every answer you get from a model is a round trip to a shed like this. What you wait, what you pay, and whether it works at all were decided by concrete poured eighteen months ago.