Uneven renewable energy supply constrains the decarbonization effects of excessively deployed hydrogen-based DRI technology
Yihan Wang, Chen Chen, Yuan Tao, Zongguo Wen
Abstract
Hydrogen-based direct reduced iron (H2-DRI) is crucial for decarbonizing the steel sector but is limited by the availability of renewable energy. Here, we propose H2-DRI deployment schemes in China’s steel sector at moderate and aggressive scales, incorporating three renewable energy sources with a resolution of 1 km × 1 km across 570 steel units. Results indicate that 52.6–55.8% of China’s current steel units lack sufficient renewable energy supply for H2-DRI deployment due to uneven distribution of these energy sources. Renewable energy can fulfill 97-100% of hydrogen demand at the moderate scale, whereas the aggressive scale requires supplemented fossil fuels accounting for one-third to one-half. H2-DRI can decarbonize steel production to 0.15–0.91 t CO2 t-1 steel at the moderate scale, but the emissions would raise by up to over sixfold at the aggressive scale. Furthermore, H2-DRI fueled by solar and wind energy exhibits poorer economic and water usage performance at the aggressive scale. We highlight the necessity of avoiding excessive H2-DRI deployment and recommend prioritizing its implementation in steel units located in regions with abundant solar and wind sources nearby. This study reveals that over half of China’s steel units lack sufficient renewable energy for hydrogen-based direct reduced iron technology. Aggressive deployment would increase carbon emissions, economic costs, and water usage in the steel sector.