For low-carbonization in the steel sector, the blast furnace method that reduces iron ore using coke and the direct hydrogen reduction method (hydrogen DRI method) that uses H₂ were compared, and carbon dioxide emissions, manufacturing cost, and issues were discussed. The carbon emission intensity attributable to raw materials was 1.9 kg-CO₂/kg for the blast furnace method and 0.06 kg-CO₂/kg for the hydrogen DRI method. The pig iron cost of the blast furnace method was 46 JPY/kg, and that of the hydrogen DRI method was 70 JPY/kg. In the hydrogen DRI method cost, the ratio of hydrogen cost to the price is very large.
　If the emitted carbon dioxide is captured for ZC (Zero Carbon) by the amine method-DAC, the carbon dioxide capture cost is 8 JPY/kg-CO₂ on a domestic storage basis. When capturing all carbon dioxide by the blast furnace method, the cost of the blast furnace method increases by 15 JPY/kg, and the actual pig iron price becomes 61 JPY/kg, which is close to the cost of the hydrogen DRI method.
　The reduction reaction of iron ore is an exothermic reaction in the blast furnace method and an endothermic reaction in the hydrogen DRI method, and it is necessary to supply energy from the outside. However, the reaction speed is high. This method is not in operation in Japan, so that there is little experience. Therefore, it is necessary to study vigorously the technological study on the optimum structure of the furnace and the streamlining of the entire steelmaking process.