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Comment by CydeWeys | Hacker News Reader

> Large semiconductor fabs use as much as 100 megawatt-hours of power each hour

Ooof, this kind of writing where the author doesn't understand units just gets my goat. Just say it uses 100 MW! Geez.

I prefer it as written, because the additional information of timeframe for measurement indicates that the author is not talking about momentary/peak power.

Which indicates the author knows nothing about how semiconductor fabs use power. Power usage is stable with a few percent...and 100MW is really on the low side for this fab. If all 6 phases are completed as they are expected to be...it's more like 250MW.

I think we can forgive the author for the low estimate considering that this project didn't exist publicly at the time of writing.

How does power usage remain stable in a fab? Please say more about how that works.

Much of the power is used for keeping air clean with temperature and humidity controlled in a very tight range. More energy is used for water cooling, waste treatment and other facilities. The rest of the power is used for production tools...which when a fab is running are generally consistent users. The power usage will scale with wafer loading, but again advanced fabs like these will run at near 100% capacity for years at a time.

I'd still much rather see "100 MW continuous" over "100 megawatt-hours of power each hour". And the former actually tells you a lot more than the latter, as with the latter it could be bursty (e.g. much more than 100 MW momentary draw), which would be a lot harder to supply. Fortunately for everyone the power draw is actually steady.

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