A Roadmap to Carbon Neutral Steel

Arcelor Mittal have launched their XCarb® programme ‘towards neutral steel’, as in carbon neutral steel. Steel is widely used the production of coins. In Europe, for example, the one, two and five cent coins are made of steel.

In 2020, steel production accounted for 8% of global CO2 emissions. While power generation, agriculture and transport were by far the largest sources of CO2 emissions, steel, building and cement were all significant sources.

Steel production has been growing steadily from about 200 million tons in 1950 to 2,000 million tons in 2021. The stock of iron and steel stock in use per capita has increased from three tons per person in 2000 to 4.3 in 2020.

Arcelor Mittal has the goal of being net zero by 2050. By 2030 it wants to reduce its CO2e emission intensity from scope 1 and 2 sources by 25%, and in Europe the target is 35%. It has a vision of steel being an enabler of a low-carbon circular economy.

If steel is made from secondary sources, scrap iron, then it produces about 0.6 tons of CO2. If it is made from iron ore, then the additional refining step means CO2 is 1-2 tons. Unfortunately, there is not enough scrap for all steel to be made from scrap iron, although that is changing quite fast. This ignores increases in additive manufacture or changes in behavioural circular economy trends.

The Direct Reduced Iron (DRI) production route could allow CO2 emissions to be reduced by 90%, with the remaining either being carbon offset or captured.

The idea is that clean electricity (renewable power and electrolysis creating green hydrogen), blue hydrogen, created by steam reforming (methane reacts catalytically with steam to form a mixture of H2, CO and CO2), and bio energy (created by using sustainable biomass in pyrolysis) are used in the DRI – Electric Arc Furnace (EAF).

While this innovative DRI technology is expected to come online from 2025, in 2020, green steel certificates were issued for steel made using the blast furnace route. These have been based on mass balancing and on CO2 savings from reducing fossil coal.

In 2022, XCarb recycled and renewably produced steel was available based on physical decarbonised steel made in electric arc furnaces using 100% renewable energy and with high recycled content.