Prospective Life Cycle Assessment Suggests Direct Reduced Iron Is the Most Sustainable Pathway to Net-Zero Steelmaking
Arezoo Azimi, Mijndert van der Spek
Abstract
High Resolution Image Download MS PowerPoint Slide Decarbonizing the steel industry is essential due to its substantial contribution to climate change. This study explores pathways to achieve net-zero CO 2eq emissions in the iron and steelmaking industry while minimizing environmental burdens beyond climate change. We conducted a comprehensive attributional life cycle assessment using the net-zero-CO 2eq -emissions framework, incorporating both conventional and prospective life cycle assessment methods, to evaluate various decarbonization strategies within the United Kingdom. All value chains were constrained to achieve net-zero CO 2eq emissions. Our findings indicate that, under a “current time” scenario, the natural gas-fired direct reduced iron with electric arc furnace is the most favorable option. This is mainly because hydrogen-based direct reduced iron production relies on the UK’s current electricity grid, which has a carbon intensity of 293.28 g CO 2eq per kWh. As greenhouse gas emissions decrease toward 2050 (approximately 70% for hydrogen-based direct reduced iron), the choice between natural gas and hydrogen will become increasingly region-specific. All net-zero-CO 2eq steelmaking case studies perform similarly on human health indicators, while the direct reduced iron with electric arc furnace options have 60–82% lower impacts on the ecosystem end point indicator than the blast furnace basic oxygen furnace routes.