The long-term aspirational objective of the Paris Agreement regarding climate change aims to limit global warming to 1.5 degrees Celsius above preindustrial standards, subsequently decreasing the occurrence and intensity of floods, droughts, wildfires, and other extreme climatic phenomena. Accomplishing this target necessitates a substantial decrease in global carbon dioxide (CO2) emissions across all economic sectors. A significant obstacle, however, could be the industrial sector, which is responsible for approximately 25 percent of global energy- and process-related CO2 emissions — especially from the iron and steel sector, the largest CO2 emitter in industry.
The current production of iron and steel heavily depends on fossil fuels (coal or natural gas) for heating, transforming iron ore into iron, and enhancing the strength of steel. Steelmaking could be rendered carbon-free by employing a variety of techniques, such as carbon capture technology, utilizing low- or zero-carbon fuels, and increasing the recycling of steel. Recently, a new study published in the Journal of Cleaner Production rigorously investigates the feasibility of various strategies for decarbonizing iron and steel production.
Today’s array of strategies encompasses boosting energy efficiency, shifting fuels and technologies, utilizing increased amounts of scrap steel, and curtailing demand. Using the MIT Economic Projection and Policy Analysis model, a comprehensive multi-sector, multi-region model of the global economy, investigators at MIT, the University of Illinois at Urbana-Champaign, and ExxonMobil Technology and Engineering Co. assess the decarbonization potential of substituting coal-based production methods with electric arc furnaces (EAF), utilizing either scrap steel or “direct reduced iron” (DRI) — either fueled by natural gas with carbon capture and storage (NG CCS DRI-EAF) or hydrogen (H2 DRI-EAF).
In a global climate mitigation scenario aligned with the 1.5 C climate target, these advanced steelmaking technologies could lead to substantial decarbonization of the iron and steel sector by 2050, provided that technology expenses remain sufficiently low for extensive deployment. Increased costs would favor transitioning from coal to electricity and natural gas, enhanced utilization of scrap steel, and diminished demand, leading to a reduction of over 50 percent in emissions compared to current figures. Lower technology expenses would facilitate widespread adoption of NG CCS DRI-EAF or H2 DRI-EAF, cutting emissions by as much as 75 percent.
Even without the implementation of these advanced technologies, the iron and steel sector could greatly lower its CO2 emissions intensity (the amount of CO2 emitted per production unit) with current steelmaking technologies, primarily by replacing coal with gas and electricity (especially if derived from renewable energy sources), utilizing more scrap steel, and instituting energy efficiency initiatives.
“The iron and steel sector must integrate multiple strategies to significantly curb its emissions by mid-century, which includes an uptick in recycling. However, investing in cost-effective hydrogen pathways and carbon capture and sequestration will allow for even greater emissions reductions within the sector,” asserts the study’s supervising author Sergey Paltsev, deputy director of the MIT Center for Sustainability Science and Strategy (MIT CS3) and a senior research scientist at the MIT Energy Initiative (MITEI).
This investigation received support from MIT CS3 and ExxonMobil through its membership in MITEI.