A niggle on cement. It’s not really about energy. Cement kilns run at >1,300 C, and need huge amounts of heat. They are very unfussy about where they get it from. Some even burn old tires, including the steel reinforcement. Green hydrogen will do; but so will green electricity, and cheaper, see previous comment. Survey of rapid progress on electric cement in Europe:
The other half of current emissions from cement comes from the *chemistry* of calcining limestone, independently of the energy used. to drive it. The key reaction is: Ca.C.O3 ⟶ Ca.O + C.O2 . No hydrogen is involved. A lot of work is going on to find alternative cements that inherently emit less CO2, or even extract it from the air during hardening, but it’s a difficult problem.
PS: All previous comments have disappeared, in Firefox, Edge and Chrome. But a link to my earlier one in a Facebook post still works.
A niggle on cement. It’s not really about energy. Cement kilns run at >1,300 C, and need huge amounts of heat. They are very unfussy about where they get it from. Some even burn old tires, including the steel reinforcement. Green hydrogen will do; but so will green electricity, and cheaper, see previous comment. Survey of rapid progress on electric cement in Europe:
https://www.cemnet.com/News/story/174030/the-electrified-commercial-cement-kiln.html
The other half of current emissions from cement comes from the *chemistry* of calcining limestone, independently of the energy used. to drive it. The key reaction is: Ca.C.O3 ⟶ Ca.O + C.O2 . No hydrogen is involved. A lot of work is going on to find alternative cements that inherently emit less CO2, or even extract it from the air during hardening, but it’s a difficult problem.
PS: All previous comments have disappeared, in Firefox, Edge and Chrome. But a link to my earlier one in a Facebook post still works.