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Comment by jeffbee | Hacker News Reader

Certainly if Germany requires a PUE below 1.3 that puts every datacenter except the big hyperscale clouds out of business. This will be yet another European regulation that shuts down local businesses and drives customers into American clouds. If such regulations spread I don't see how makers of traditional datacenter junk can survive. Operators with PUEs < 1.1 are not using UPS, managed PDUs, redundant hot swappable power supplies in servers, CRACs, or any of that crap.

Of course I think regulating the PUE is a terrible idea. This is yet another aspect of the economy that is better-regulated by a carbon tax.

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Hetzner (German data center provider) claims to achieve a PUE of 1.1 (https://www.golem.de/news/besuch-im-rechenzentrum-so-betreib...), admittedly their cloud offerings are quite limited but I think they are expanding on that front. So it doesn’t seem like only hyper scalers would fall into that limit.

Hetzner runs an intentionally primitive shop. Famously, one of their (historic) cheapest offerings were desktop "servers" on wooden shelves with flying cabling. So anything in the way of UPS, PDUs, monitoring, airflow, etc just isn't there, keeping PUE low.

Yes, and I think this leads to a more sophisticated analysis than PUE gives us, because a shop like Hetzner puts more of the burden for reliability and availability on the customer, compared to an Amazon or Google who internalize as much of the redundancy and replication that they can manage.

An example of where the PUE analysis really fails: I have two facilities, one on each American coast, and they operate in a primary-spare arrangement. This is far, far less energy efficient than if I have 20 datacenters all over the place and I am prepared to lose 2 of them at any time. In the latter architecture I am using much less energy, but enjoying much better reliability. PUE does not capture this type of architectural waste. It also fails to reflect the problem of burning megawatts because you are running your logs analysis pipeline in Perl or whatever.

> Amazon or Google who internalize as much of the redundancy and replication that they can manage

Please.

That wasn't much of a refutation. In the cloud you can move up the food chain to get durability and availability without thinking about it. It is much more efficient (and way, way easier to manage) to just chuck your data into Cloud Spanner than it would be to operate a geographically diverse triplet of Postgresql instances.

Your statement was a weasel word packed claim. They do not "pack as much as they can manage" for any civilians definition of manage.

Restaurants use as little salt in your food as they can manage.

In case anyone else was wondering:

> Power usage effectiveness (PUE) is a metric used to determine the energy efficiency of a data center. PUE is determined by dividing the total amount of power entering a data center by the power used to run the IT equipment within it. PUE is expressed as a ratio, with overall efficiency improving as the quotient decreases toward 1.0.

From https://www.techtarget.com/searchdatacenter/definition/power...

Doesn't sounds like it accounts for computing efficiency then? That would probably be quite impossible or at least very difficult anyway. Of course, it's still great for a datacenter to actually use its energy for running the computers instead of just AC and transformers.

Heat recovery from datacenters for district heating is one way to increase the efficiency; I wonder if it impacts PUE?

Even worse, a future requirement will be compulsory use of waste heat. No matter the cost or efficiency, you have to find users for the heat given off by your cooling. Good luck finding people wanting their homes heated in summer...

What a stupid waste of resources.

That capital would be much better invested building solar farms or transmission capacity.

I guess that’s what you get for trash-talking liberalism for decades.

solar farms are land intensive not just capital

You can actually use the land under solar panels for grazing if you space them off the ground. This is especially true as it gets hotter.

Or for buildings.

Is Germany doing this? Or planning to?

Planning. https://www.zeit.de/digital/2023-04/bitkom-rechenzentren-abw...

Oh no.

It is an excellent idea, so are having "waste heat networks". You could then make a heat sink at scale that is also a reservoir for reuse. This would be as simple as installing another water loop that services location just like our existing water system.

Of course the details need to be worked out, but if a business district had a WHN, it would make it easier for mom-and-pop datacenters to built in urban environments.

It wouldn't be that much different than the steam loops that lots of existing cities have in their downtown core.

On the contrary, it can be extremely difficult and expensive to do with waste heat from datacenters. Your average cooling equipment, of the energy conserving kind has 2 modes:

First mode, for cold outside weather e.g. in winter is free cooling, where you just use convection or fans to bring in cool outside air, push out warm inside air (there are also variants of this like "tokyo wheel", but those are unsuitable for heat reuse). You could at best use the warm air output (~25°C) to directly heat neighboring buildings, but the air ducts you need for that will be massive. Comfort level in the buildings heated this way will be low due to high air velocity and associated noise. Also, air ducts are a fire hazard and high maintenance to keep dust and vermin out.

The other mode is water cooling (either direct or indirect) where you cool your servers directly by water or the air through water radiators. The warm water is then either cooled down with outside air, outside air plus evaporation (both possible only when it is not too warm outside) or compressive cooling (aka heat pump, the usual big MW-scale machines in the cellar). In those cases, district heating will only be possible if you can reach a sufficient water temperature somehow. E.g. directly cooling your servers uses at most 30°C intake and outputs at most 50°C. District heating usually runs at 70°C, so you would need a running heat pump to make up for the 20K difference. When the servers are indirectly air-cooled, the difference will be even larger. So you will always need those big MW-scale heatpumps running, just to make use of your waste heat, at great expense and for the uncertain benefit of maybe selling your heat to neighbors. This is deadly for mom-and-pop datacenters because of the uncertainty (maybe you can sell your heat, maybe it'll be too expensive) and the huge investment, your cooling equipment will be far larger (more and bigger heatpumps), more expensive, redundant (because in summer you will still need to have equipment to give of heat into the outside air).

All the sufficiently large customers I know of are looking to move abroad, for this reason and the astronomical cost of electricity in Germany.

Thanks for the reply.

I think most DC equipment should have built in coolant loops, standardized to the point where you can order all the equipment and just plug it in.

Spec that DC components can run at a much higher temperature.

The issue is that DC operators get to trade money for a natural resource (water, power) for lower up front build costs. Owner operators do a much better job, but Google still extracts billions of gallons of water from municipal supplies, often even ground water which I think should be a crime.

I'd also like to see the cost of cooling be passed on to the cloud customer. Mixing it into the hourly price causes a tragedy of the commons.

But cost of cooling is passed on to the cloud customer. Different zones/DCs/regions have different hourly cost which is a function of, among other things, the local price of electricity and cooling.

It is very resource - intensive to build these low-grade waste heat networks, and you could achieve much more for the climate by NOT building them and investing the effort elsewhere - for example in building out renewable energy sources.

The market is very good at figuring these things out and you can push it in the right direction by putting a price on carbon.

Or you just do what Texas does and let Solar rip.

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