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0 pointsfilleokus4y ago0 comments

Huh, that's interesting!

I wonder, in a strictly thermodynamic way (ignoring CO2 etc), how big of an impact it would have to remove all internal combustion engines in land-based transportation and power generation (coal plants).

ICE's have like a 30-40% efficiency? Compared to electric engines 80-90%. But on the other hand, you probably consume quite a bit of energy producing the batteries...

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ben_w4y ago

Per battery or overall to the planet?

Per unit of storage, Wikipedia says the lifetime storage capacity of batteries etc. relative to energy needed to construct them is:

Lead acid: 5 times construction energy; Vanadium redox: 10; LiIon: 32; Pumped hydro: 704; Compressed air: 792.

I can’t remember where I’ve seen this, but I think a unit of PV produces all the energy it took to manufacture after a month or two.

If you mean overall? As a rough guide we emit about 35GT CO2/year which is about 9.5e12 kg carbon; burning carbon releases about 32MJ/kg; so about 3e20 J/year, or 9 TW, or 19 mW/m^2.

There’s more energy in the hydrogen in gases and oils, this is just a ballpark estimate of the thermodynamic output of burning that much does to directly heat the planet.

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