H2 Green Steel, a Swedish steel manufacturing company founded in 2020, aims to minimize the carbon footprint of steel production. By incorporating green hydrogen into its steelmaking process, the company effectively reduces COâ‚‚ emissions, addressing the significant environmental impact of traditional steel production, which accounts for approximately 8% of global COâ‚‚ emissions..
Challenge: steel industry carbon emissions
In 2023, global crude steel production reached nearly 1.9 billion tons, with China leading the way by contributing 54% of the total output. The steel industry is notably emission-intensive, responsible for approximately 8% of worldwide carbon dioxide (COâ‚‚) emissions. Over the past decade, COâ‚‚ emissions from the iron and steel sector have increased, driven by rising steel demand and the energy required for production. Each ton of steel produced resulted in an average emission of 1.85 tons of COâ‚‚. Steelmaking generates over three billion metric tons of COâ‚‚ annually, making it the industrial material with the most significant impact on climate.
H2 Green Steel Technology
The traditional steel production process primarily involves two main methods: the blast furnace-basic oxygen furnace (BF-BOF) route and the electric arc furnace (EAF) route.
The BF-BOF route process is depicted in the diagram below.
Iron ore, coke, and limestone (CaCO₃) are introduced into a blast furnace to produce pig iron (hot metal). Coke serves as a fuel to heat the furnace, releasing carbon monoxide (CO) as it burns. This CO reacts with the iron oxide (Fe₂O₃) in the ore, reducing it to metallic iron (Fe). Limestone acts as an additional carbon monoxide source and a "flux," combining with infusible silica (SiO₂) in the ore to form fusible calcium silicate (CaSiO₃). This calcium silicate, along with other impurities, forms a slag that floats on the molten iron.
The molten pig iron is then transferred from the blast furnace to the basic oxygen furnace (BOF), where it is mixed with scrap steel. Pure oxygen is blown into the furnace, igniting the carbon dissolved in the steel and converting it into CO and CO₂, which raises the temperature to about 1700 ºC. This process melts the scrap, reduces the carbon content of the molten iron, and helps eliminate unwanted chemical elements.
The EAF process is depicted in the diagram below.
Scrap steel or direct reduced iron is charged into the furnace, where electric arcs generated between graphite electrodes and the scrap create intense heat, melting the metal. Natural gas, carbon, lime, and oxygen provide additional heat and assist in slag development during the melting process. The molten steel is refined to remove impurities, primarily through oxidation reactions. The impurities form a slag that is removed to ensure the purity of the steel. Once the desired composition and temperature are achieved, the molten steel is tapped from the furnace and can be cast into various shapes for further processing.
The EAF method is generally less carbon-intensive than the BF-BOF route, as it relies on electricity rather than coke. However, the carbon footprint of the EAF process can vary depending on the electricity source used.
H2 Green Steel has pioneered an innovative method to decarbonize the steel manufacturing industry. The company employs green hydrogen in the direct reduction of iron, producing solid iron sponge. This sponge iron is subsequently refined into crude steel using an electric arc furnace (EAF). By integrating hydrogen-based direct reduction of iron (H2-DRI) with EAF, the process eliminates the need for pig iron production and substantially cuts carbon emissions.
At its plant in Boden, northern Sweden, H2 Green Steel generates green hydrogen to enable the production of green steel. The facility operates with over 700 MW of installed capacity, utilizing standardized 20 MW electrolysis modules to produce green hydrogen. Electrolysis, the process used, involves splitting water into hydrogen and oxygen using electricity. The electricity for this process is derived from renewable sources, mainly hydropower from the nearby Lule River and wind power from local wind farms.
How H2 Green Steel produces green steel
The diagram below depicts the process of H2 Green Steel to produce green steel.