The 500k-ton typo: Why data center copper math doesn't add up

[Fiveplus]

The funniest part is beyond the typo, the complete lack of physical intuition from the analysts who circulated this. 500,000 tons is roughly the weight of 1.5 Empire State buildings. If your rack busbars weigh more than the structural steel of the facility housing them, you have a geotechnical engineering crisis on your hands. It is wild that we reached a point where financial modeling is so decoupled from physical reality that nobody paused to ask if the floor would collapse.

[lm28469]

When I asked gemini it got it right away and as a source it provided a link to your comment... what a time to be alive, I hope you got the Empire State buildings calculations right because you're now part of the Truth ™

https://imgur.com/a/NaTfvtS

[Aurornis]

The world of financial analysis and modeling is broad. It’s common to give these tasks to juniors and expect them to grind through it when the output doesn’t really matter.

In this case the output wasn’t actually used for financial modeling. If it had been, it would have been caught immediately when someone put it into a table where they calculated the price or the supply constraints or anything else.

[viggity]

Kinda like when someone said that instead of running for mayor, Bloomberg could have given everyone in the country $1M. A guest said it on NBC and Bryan Williams, nor the pundit had any intuition that it seemed grossly wrong. https://www.politifact.com/factchecks/2020/mar/06/msnbc/bad-...

[matthewaveryusa]

Just to make it even more real: During covid I added a sub-panel and the wire (more like the sausage given the girth) between the sub-panel and main panel was aluminum because of cost. You just need to be a tad careful at the connection points with copper -- nothing a caring literate person can't handle

[franktankbank]

I wouldn't be surprised if that part was not really reviewed by an expert. They have the unit mass correct but maybe an editor is like ok but what does this look like for a gw project? It doesn't take more than 3rd grade math and a pocket calculator to do it correctly but journalist hasn't had to fumble that ball before. An expert knows its all too easy for any person to make that mistake and would second guess their own work.

[carlesonielfa]

My first thought was, this is the kind of thing that an LLM writes and nobody checks. But then I realized, any decent LLM would have probably caught that inconsistency

[cyanydeez]

Do we think the people pushing new age LLM saviors are more or less stupid?

[schainks]

2008 would like a word.

[crote]

With regards to the copper market: it keeps surprising me that some people seem to assume copper is a hard requirement for conducting electricity.

In reality copper is just convenient. We use it because it's easy to work with, a great conductor, and (until recently) quite affordable. But for most applications there's no reason we couldn't use something else!

For example, a 1.5mm2 copper conductor is 0.0134kg/m, which at current prices is $0.17 / meter. A 2.4mm2 aluminum conductor has the same resistance, weighs 0.0065kg/m, which at current prices is $0.0195 / meter!

Sure, aluminum is a pain to work with, but with a price premium like that there's a massive incentive to find a way to make it work.

Copper can't get too expensive simply due to power demands because people will just switch to aluminum. The power grid itself had been using it for decades, after all - some internal datacenter busbars should be doable as well.

[dzink]

You just have to not mix and match. If you mix them the two need special bonding at every single connector or they can cause arching and fires.

[y-curious]

I am not an electricity/wiring guy so maybe you can help me understand. I thought aluminum is dangerous to wire with because it is a fire hazard (I bought a home this year and this was a prominent warning in my reading). Is that because it needs to be done very carefully? I imagine most data centers would not mess with a fire risk on such a scale.

[nerdralph]

Most residential 200A electrical panels use tin plated aluminum busbars. https://www.eaton.com/cr/en-us/catalog/power-connections/bus...

[pfdietz]

One good reason for moving from copper to aluminum is that copper contaminates recycled steel, but aluminum doesn't. Fortunately these days it's profitable to carefully extract most of the copper wire and such from scrap steel before it's melted down.

[zahlman]

> In the Earth's crust, aluminium is the most abundant metallic element (8.23% by mass[68]) and the third most abundant of all elements (after oxygen and silicon).

TIL. I thought it would be relatively expensive due to the difficulty of extracting it.

(Iron is much cheaper than I thought, too.)

[candiddevmike]

AFAIK Aluminum wires will become a heat liability, especially at higher amps

[kmbfjr]

Aluminum conductors are dangerous unless the entire system is designed for it. It is not a case of switching to something cheaper.

Look at the electrical fires of the 1950’s and 1960’s as an example, and that was at household levels of current.

Aluminum is used, but everything accounts for the insane coefficient of linear expansion and other annoying properties.

[nirui]

> In reality copper is just convenient. We use it because it's easy to work with, a great conductor, and (until recently) quite affordable

It's convenient, it's easy to work with, great conductivity, and cheap enough all at the sametime... Dude, I think you just explained why cropper is used instead of anything else.

[amluto]

> Sure, aluminum is a pain to work with

Really? In larger sizes, an equivalent ampacity aluminum cable is generally lighter and more flexible than copper. The main downside is that it’s thicker.

(Common terminations for larger wire sizes are often dual-rated for aluminum and copper. The engineering details for how to design lugs that work well for aluminum and copper were worked out long ago.)

[fedeb95]

interesting, thanks!

[daeken]

This sort of mistake is easy to make when you're mixing up your units; if they kept to one system of measure, it would've been trivial to catch, before or after release.

[testplzignore]

We need to standardize on using Earth circumferences as the unit of length. Or better, football fields! (the type of football of course being implied by the website's ccTLD)

[eterm]

If only there were some kind of international system of standard units.

[NoNotTheDuo]

Amazingly ironic that in an article about a typo, there is a typo.

> "Tat sounds like the ultimate catalyst for the commodities market and copper has been hitting records."

"Tat" should be "That", imo.

[NooneAtAll3]

you should've made a typo as well, as per tradition

[zekyl314]

I saw this too, awesome to report on a typo when you yourself have a typo. What are the odds?

[sidewndr46]

I interpreted the typo as a meta commentary on the state of journalism in the 21st century.

[compressedgas]

The error in the original article has been corrected.

https://developer.nvidia.com/blog/nvidia-800-v-hvdc-architec...

[mrbonner]

It’s interestingly related that Amazon is also buying a copper mine: https://www.wsj.com/finance/commodities-futures/amazon-is-bu...

[flakeoil]

They don't buy a mine they buy the output.

[nine_k]

> If the "half a million tons" figure were accurate, a single 1 GW data center would consume 1.7% of the world's annual copper supply. If we built 30 GW of capacity—a reasonable projection for the AI build-out—that sector alone would theoretically absorb almost half of all the copper mined on Earth.

Quickly doing such "back of an envelope" calculations, and calling out things that seem outlandish, could be a useful function of an AI assistant.

[9dev]

Using your brain is so vastly more energy efficient, we might just only need half of that 30 GW capacity if fewer people had these leftpad-style knee-jerk reactions.

[CamperBob2]

Nobody on HN is a bigger AI stan than I am -- well, maybe that SimonW guy, I guess -- but the truth is that problems involving unit conversions are among the riskiest things you can ask an LLM to handle for you.

It's not hard to imagine why, as the embedding vectors for terms like pounds/kilograms and feet/yards/meters are not going to be far from each other. Extreme caution is called for.

[Gravityloss]

I think this is exactly the thing that should be done by a person without AI, to check what AI is writing.

[kergonath]

It’s one of the useful functions of an engineer.

[jandrewrogers]

These kinds of errors are not rare in the media.

Even among engineering fields routine handling of diverse and messy unit systems (e.g. chemical engineering) are relatively uncommon. If you work in one of these domains, there is a practiced discipline to detect unit conversion mistakes. You can do it in your head well enough to notice when something seems off but it requires encyclopedic knowledge that the average person is unlikely to have.

A common form of this is a press release that suggests a prototype process can scale up to solve some planetary problem. In many cases you can quickly estimate that planetary scale would require some part of the upstream inputs to be orders of magnitude larger than exists or is feasible. The media doesn't notice this part and runs with the "save the planet" story.

This is the industrial chemistry version of the "in mice" press releases in medicine. It is an analogue to the Gell-Mann amnesia effect.

[bradfa]

With a higher voltage you can reduce your copper needs by a substantial amount. Seems if copper cost was a concern this would be what these data centers would do.

[sidewndr46]

Agreed. I was kind of surprised to see 54 VDC mentioned. I am assuming this is low enough to meet some threshold for some kind of safety regulation. In other words, it doesn't shock you just 220 VAC would. I'm not entirely convinced of that however as it turns out bus bars are really dangerous in general. A 54 VDC bus bar won't shock you, but if you drop even a paperclip between the bus bar and a metal part that is grounded it basically disappears instantly in a small blast of plasma. The injury from that can be far worse than any shock you'd receive.

[hireshbrem]

I wonder how many 'innocent' inaccurate data is taken by journalists to use for their agenda. I think this happens a lot in the age of AI.

[JohnMakin]

Efficient markets!

[tlb]

Checking the arithmetic in every paper published seems like an good use case for LLMs. Has someone built a better version than uploading a PDF to ChatGPT and asking it to check the arithmetic?

[ironbound]

LLM's are why we're in this mess, they can't do math or count r's