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

Original Article ↗ Hacker News Discussion ↗

Unit mix-ups and numeracy

  • Commenters see the “500k tons of copper” error as a classic unit/scale mistake that basic dimensional sanity-checks should catch.
  • Jokes about non-SI “units” (football fields, Olympic pools, bananas, elephants, cheetahs) underline frustration that people don’t stick to consistent standards.
  • Some recall the historical definition of the meter (Earth meridian fraction) and note that we already indirectly use “Earth circumferences” as a base.

AI/LLMs as arithmetic checkers

  • Many argue this is a perfect task for LLMs or tool-using “reasoning” models: back-of-envelope checks, verifying that quantities are within plausible bounds.
  • Others are skeptical, noting LLM failures at counting and unit conversion, and warning that similar-looking unit tokens (lb/kg, ft/m) can confuse models.
  • A counterpoint is that modern models plus calculators are strong at routine arithmetic and would likely have flagged the copper claim.

Energy efficiency: brains vs AI

  • One thread compares energy cost of human reasoning versus AI queries. Rough numbers suggest a single careful human check is lower energy than an LLM call, but humans are “always on” whereas AI can be spun up on demand.
  • Some argue AI can already be more energy/CO₂-efficient than humans on certain narrow tasks; others point out that training and infrastructure energy must be included, just as human upbringing and lifestyle energy should be.

Copper demand and market impact

  • Several highlight how trivial it is to see that 500k tons per 1 GW implies absurd fractions of annual global copper production, so the claim was obviously off by orders of magnitude.
  • This is used as an example of a sanity-check engineers routinely do, and that journalists and financial analysts often skip.

Copper vs. aluminum for conductors

  • A substantial subthread notes copper is not a hard requirement: aluminum can provide the same resistance at larger cross-sections and far lower material cost.
  • Aluminum is already used widely in power grids and busbars, and many lugs/panels are dual-rated for Cu/Al.
  • Fire risks with aluminum are tied to oxidation, higher thermal expansion, bad terminations, and especially older alloys and DIY residential work; in professional, well-designed data centers, commenters think it’s manageable.
  • There is disagreement over how dangerous aluminum is in general, but consensus that:
    • It demands proper connectors, torqueing, sometimes antioxidant paste, and design for expansion.
    • It’s a poor fit for small-gauge DIY home wiring, but reasonable for large, engineered feeders and busbars.

Physical intuition, media, and finance

  • Many see the copper error as symptomatic of a broader lack of physical intuition in media and finance: numbers that imply ludicrous masses (e.g., >1 Empire State Building of copper per facility) go unchallenged.
  • Similar examples are cited where journalists mis-handle orders of magnitude (e.g., money per person) because “sounds good” beats “is correct.”
  • People note such scaling errors are common in “planet-saving” tech stories and industrial chemistry coverage.

Power distribution design

  • Commenters note that higher voltage distribution (hundreds of volts DC) greatly reduces copper needs compared with 54 VDC, but safety and regulatory thresholds drive choices.
  • Even at “safe” voltages, exposed high-current busbars are dangerous due to arcing and plasma from short circuits, so mechanical protection is crucial.

Miscellaneous

  • The original Nvidia text has been corrected; people joke about the article itself containing a typo while reporting on a typo (invoking “Muphry’s law”).
  • There’s brief mention of Amazon contracting copper output, and a wry one-liner: “Efficient markets!”