Decoupling heavy industry from fossil fuels requires moving away from coal and gas as chemical reagents, not just heat sources. For steel, the primary shift involves replacing coke-based blast furnaces with hydrogen-direct reduction (H-DR). This process uses green hydrogen to strip oxygen from iron ore, leaving only water vapor instead of CO2. Scaling this requires massive electrolyzer capacity and advanced electrode materials that can withstand extreme temperatures.
Cement production faces a different hurdle. Most emissions come from the chemical reaction called calcination, where limestone turns into lime. Even if we use renewable electricity for heat, the chemical reaction itself releases carbon. Breakthroughs must focus on carbon capture and storage (CCS) integrated into kiln designs, or developing alternative binders like magnesium-based cements that absorb CO2 during curing.
Silicon manufacturing demands intense, steady heat for melting quartz. To ditch coal, we need breakthroughs in electric arc furnace (EAF) efficiency and perhaps molten salt heat storage to smooth out the intermittency of wind and solar. We also need better recycling technologies to recover silicon from old solar panels, reducing the need for virgin ore processing altogether. These shifts move us from combustion-based chemistry to electrochemical and thermal-electric workflows.
