Zero-carbon steel
Steel is valued for its strength and malleability when heated, and to make it, one needs pure iron and a small amount of carbon. Iron is abundant in the earth's crust, but it is typically combined with oxygen and other elements in iron ore. To produce steel, one must separate the oxygen from the iron and introduce a small amount of carbon. This is typically achieved by melting iron ore at high temperatures with a type of coal called coke, which releases carbon and allows some of it to bond with the iron. However, this process also produces a significant amount of carbon dioxide, contributing to climate change.
To address this issue, the green premium for "clean steel," which incorporates carbon capture to reduce emissions, currently adds 16-29% to the cost of production. To reduce this premium, we need to develop reliable sources of clean electricity, which already account for a quarter of the energy used in manufacturing worldwide. Electrification is another option, where electricity replaces fossil fuels in industrial processes such as steel making. For example, one approach involves using clean electricity instead of coal. Another promising technique, called molten oxide electrolysis, involves using electricity to break down iron oxide into pure iron and oxygen without producing carbon dioxide. However, these ideas have yet to be proven at an industrial scale.
Recycling more steel alone is not sufficient to eradicate greenhouse gas emissions, although it can contribute. We should strive to recycle more materials and discover innovative methods to reduce the energy required for recycling. Furthermore, since reusing a product consumes significantly less energy than recycling it, we must also explore ways to construct and manufacture items using repurposed materials. In addition, we can design buildings and roads to minimize the utilization of steel, and in some situations, cross-laminated timber, which is composed of layers of timber glued together into a stack, is strong enough to serve as a substitute.
Gates, Bill. How to Avoid a Climate Disaster (p. 100-110). Penguin Books Ltd. Kindle Edition.