I would expect a large provider like Hetzner to refresh hardware continuously - every year a fraction of old hardware is retired and replaced by new. Given price shock they could stop doing this but older hardware is less energy efficient and has limited life anyway.
Hetzner mostly ate up the rising energy prices in germany for the last 3 years and they have big problems with their hardware supply since then. It is hard to get cloud instances in nbg and fsn. So an increase in pricing is very much expected from my side.
German electricity prices have been falling for the last 3 years. They've been below the pre-war levels for a while now.
Hardware prices, especially with the current chaos, and the huge spike in demand they've doubtless seen is more than enough to explain this price hike though.
In their email they say their operating costs increased too. Whether it actually did or not, that is their reasoning to increase prices on already sold products.
A PUE of 1.00 means all of your electricity is used for compute and none for cooling (and other things). "as much electricity for cooling as you spend of compute" would be a PUE of 2. It's "total / compute". And PUE of 2 would be quite bad, most facilities are better than 2.
Thanks. Looks like I misremembered the formula. We run way lower than 2. I have seen some systems running with 1.0x values (I don't remember the exact value).
However, this doesn't mean that the increase in energy costs are not affecting Hetzner.