Concrete is a bit of a double whammy, because, typically, you are emitting CO2 during both the process of creating cement (to create high heat to drive oxygen off limestone), and then again when it cures.
Both contributions of the CO_2 emissions are from the production procedure: The CO_2 of the heat generation and CO_2 (not oxygen) being released from e.g. limestone CaCO_3 -> CaO + CO_2.
A decade or more ago, on the Low Tech website ( which I still find ironic ), I pointed-out that a solar-concentrator is THE ideal method for roasting the ingredients of cement, instead of using conventional/fossil energy.
Use solar-concentrator for the roasting, you can reach any temperature you want, I think the way to make solar-concentrators not kill birds ( flash-incineration ) is with either sound they don’t like, or with making a dome over the entire site, & just putting a sparse “spiderweb” of fiberglass strands over it, so as to keep them away.
So long as the concentrator is still able to work, it’d be good-enough, & it would detach cement-manufacturing from the conventional energy-sources, for the heat.
( moving the materials would still cost electricity, but that’s minor, compared with the roasting )
That sounds awesome! Do you have a link to the article you wrote?
