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- 01 30, 2025
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At the steelworksAG near the German city of Salzgitter, ironmaking is a dramatic affair. Red-hot molten metal pours forth from the bottom of towering blast furnaces. The noise is deafening. Sparks fly everywhere. Soon things will be much more sedate. Seven wind turbines already tower over the site, run by a firm called Salzgitter . In a few years the electricity they generate will power banks of electrolysers, container-sized machines that split water into oxygen and hydrogen. The hydrogen will replace coke in reducing iron ore to iron in a new type of furnace, which will operate at much lower temperatures. Instead of CO, the process will emit HO.The fireworks will be gone—but the climate will be grateful. Conventional steelmaking emits carbon dioxide twice over: first to generate the intense heat needed to force the coke to react with the ore in the blast furnace; then in the chemical reaction itself, as the coke snatches oxygen atoms from the ore to form iron and CO as a by-product. As a result, steelmakers account for between 7% and 9% of annual global carbon emissions, about as much as India and not much less than road transport. The Salzgitter steelworks alone contribute around 1% of Germany’s total emissions. No global net-zero goal will be possible to attain if the industry’s belching is not radically reduced, says Julia Reinaud of Breakthrough Energy, a fund which invests in climate-friendly technology.