In his 2021 book How to Avoid a Climate Disaster, Bill Gates lists 19 technologies needed to achieve net-zero carbon emissions by 2050. Two of these technologies focus on construction materials: zero-carbon cement and zero-carbon steel.
When Gates uses the term “zero-carbon,” he doesn’t mean steel, concrete or cement without any carbon atoms; he means that greenhouse gas emissions from the manufacture and transport of these products are zero. Alternatively, he means “net-zero,” where emissions are offset by removing GHGs from the atmosphere. In addition to the list of technologies, Gates includes a factor for each called the “green premium.” This green premium is the additional cost of choosing a zero-carbon option over the current GHG-emitting one.