Cost and Life Cycle Analysis for Deep CO₂ Emissions Reduction for Steel Making: Direct Reduced Iron Technologies

Among heavy industrial sectors worldwide, the steel industry ranks first in carbon dioxide (CO2) emissions. Technologies that produce direct reduced iron (DRI) enable the industry to reduce emissions or even approach net-zero CO2 emissions for steel production. Herein, comprehensive cradle-to-gate (CTG) life cycle analysis (LCA) and techno-economic analysis (TEA) are used to evaluate the CO2 emissions of three DRI technologies. Compared to the baseline of blast furnace and basic oxygen furnace (BF-BOF) technology for steel making, using natural gas (NG) to produce DRI has the potential to reduce CTG CO2 emissions by 33%. When 83% or 100% renewable H-2 is used for DRI production, DRI technologies can potentially reduce CO2 emissions by 57% and 67%, respectively, compared to baseline BF-BOF technology. However, the renewable H-2 application for DRI increases the levelized cost of steel (LCOS). When renewable natural gas (RNG) and clean electricity are used for steel production, the CTG CO2 emissions of all the DRI technologies can potentially be reduced by more than 90% compared to the baseline BF-BOF technology, although the LCOS depends largely on the cost of RNG and clean electricity.