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Comment by tomarr | Hacker News Reader

Unfortunately not and that is one of the main issues. Even if we had limitless carbon-free energy there would still be significant carbon outputs directly from the production process. The article shows one possible way of reducing this for steel, but cement is currently a different ballgame and is a substantial emissions source from its non-energy inputs.

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Well with cheap carbon free electricity, we could cut all the CO2 emissions from iron and steel with hydrogen based reduction and about half that of cement manufacture (about half the carbon use is energy cost for heating as per Wikipedia article). Together about 15% of global emissions could be eliminated which is nothing to sneeze at.

In fact many intractable problems in the world can be solved by more clean electricity - eg. 8000 odd skyscraper farms are enough to feed the world eliminating farm-land requirements but would require enormous amount of energy to run - also would represent single points if failure to attack in war - so will need society to evolve

Well they seem to have found a way to decrease carbon emissions while producing cement as well. https://www.bloomberg.com/news/articles/2019-08-30/builders-...

I think there is a hydraulic magnesium silicate hydrate cement that can be made from seawater-derived magnesium without carbon emissions if electricity is cheap enough. These aren't trivial engineering challenges, but they are probably solvable.

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