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Comment by littlestymaar | Hacker News Reader

> Plastic is relatively cheap, energy-wise. Your embodied energy usage is dominated by semiconductors.

Given how energy costly cement is, and how much quantity we use, I'd be really surprised if it didn't dwarf semiconductors by several orders of magnitude.

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Concrete takes 1.1MJ/kg to manufacture[1]. So, you get ~4000kg of concrete for one laptop's worth of embodied energy. Amortised over the expected lifetimes of the items in question, manufacture of high-density electronics still represents our greatest usage of energy.

[1]https://en.wikipedia.org/wiki/Embodied_energy

Thanks for this. Something to keep in mind - concrete weighs an awful lot and comes in at 2.2-2.5 tons per cubic meter. That 4000kgs is less than 2 cubic meters of concrete.

If it’s reinforced steel the energy usage leaps up.

Building is incredibly energy intensive and very wasteful.

Thanks for your link, it’s really interesting.

Yeah, concrete is dense and we use a enormous amount of it! We're making 4 billion tons of concrete each year, nnd without even counting the energy needed for transporting it (which is also high, because of the enormous mass involved), concrete production represent 8% of the total CO2 emissions!

https://www.archpaper.com/2019/01/concrete-production-eight-...

I'm wondering whether the 1.1MJ/kg takes into account that the heat used for cement production is often used for heating nearby households.

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