Goodbye, Coal! This Project Makes Steel With Green Hydrogen
Source：eepower
Conventional steel-making requires intense heat, typically generated with fossil-fuel-powered blast furnaces. The process produces significant amounts of carbon emissions and other pollutants.
A Swedish project called HYBRIT (Hydrogen Breakthrough Ironmaking Technology) aims to change steel production by introducing a hydrogen-based steelmaking that offers a transformative approach to reducing greenhouse gas emissions by replacing carbon-intensive processes with cleaner chemical reactions.
HYBRIT production plant. Image used courtesy of HYBRIT
What Is HYBRIT?
The HYBRIT project is a collaboration between Swedish companies SSAB (steel), LKAB (mining), and Vattenfall (energy). The group has pioneered fossil-free steel production by replacing coal with hydrogen.
HYBRIT has completed its pilot project for hydrogen gas storage and reported the findings to the Swedish Energy Agency. The results show that it is technically possible to store fossil-free hydrogen gas to produce fossil-free iron and steel on an industrial scale.
HYBRIT’s underground hydrogen storage facility. Image used courtesy of HYBRIT
Hydrogen’s low energy density necessitates costly storage, usually in high-pressure tanks or using cryogenic liquefaction, and dedicated pipelines. HYBRIT has proven that it is technically feasible to store hydrogen in steel-lined rock caverns—fossil-free hydrogen gas that can be used to produce iron and steel on a large industrial scale, potentially reducing the costs of hydrogen production by up to 40%.
Traditional Steelmaking vs. Hydrogen-Based Methods
Conventional blast furnaces use coke (processed coal) to produce carbon monoxide (CO), which reduces iron oxide (Fe₂O₃) in a reaction that releases CO₂: Fe2O3+3CO→2Fe+3CO2
At present, this process accounts for roughly 7 to 9% of global CO₂ emissions.
Hydrogen direct reduction (H-DR) replaces CO with hydrogen (H₂) in a reaction that produces water vapor instead of CO₂: Fe2O3+3H2→2Fe+3H2O
This reaction occurs in a reactor vessel at 600–800°C, powered by renewable electricity, bypassing the need for 1,500°C blast furnaces.
Green hydrogen, produced via water electrolysis powered by renewable energy, can be used to produce H-DR steel. If renewables power the electric arc furnace (EAF), the result is an effectively carbon-neutral process, avoiding 1.8 tons of CO2 per ton of steel produced. HYBRIT’s pilot plant uses 500 MW alkaline electrolyzers, powered by wind and hydropower, to split water into hydrogen and oxygen.
The Hydrogen Storage Solution
Hydrogen’s small molecule size makes it difficult to store as it will leak past most seals and gaskets. In addition, green hydrogen production costs spike when renewable energy is unavailable. Storing hydrogen during surplus renewable generation (during windy periods, for example) reduces reliance on grid electricity. The HYBRIT project has addressed these challenges through innovative engineering and large-scale testing of a hydrogen-resistant steel-lined, underground rock cavern.
In HYBRIT’s testing, a steel-lined 100 cubic meter (m³) pilot cavern (expandable to 100,000–120,000 m³) was constructed to store enough hydrogen to supply a steel plant for 3 to 4 days. Hydrogen is stored in the rock cavern at 250 bar pressure and is delivered to the local steel plant via dedicated pipelines. The cavern is located 30 meters underground to minimize explosion risks. Advanced monitoring systems also ensure the storage system’s safety.
The HYBRIT pilot system was validated with 94% operational availability over 3,800 hours of testing and a confirmed 50-year lifespan for the steel lining through cyclic pressure testing.
Pilot Plant Validation
In 2024, the pilot plant in Luleå, Sweden, produced 5,000+ tonnes of high-purity sponge iron, with zero CO₂ emissions. The iron produced achieved 99 percent metallization and exhibited improved aging resistance when compared to blast furnace iron, enabling easier handling and transport.
The next phase is the construction of a 1.2 million-tonne/year plant in Gällivare, Sweden, slated to begin operations in 2026. It will replace existing blast furnaces with a 500 MW electrolyzer to produce hydrogen and modified EAFs to handle hydrogen-reduced iron.
Hydrogen Steelmaking Challenges
Hydrogen-based steelmaking is not without challenges. Current green hydrogen costs ($3–$6/kg) are two to four times higher than the $1.5–$2/kg needed for competitiveness with coal. Electrolysis inefficiencies (70–80% efficiency for PEM systems) and renewable electricity prices are significant cost drivers. H-DR production can require significantly more electricity per ton of steel than conventional methods, making the use of renewable energy mandatory. H-DR also requires high-purity DR-grade iron ore, which accounts for only about 4% of the current global supply. At present, capital costs for hydrogen infrastructure (such as electrolyzers and reactors) are two to three times higher than blast furnace retrofits. Without subsidies or carbon taxes, hydrogen steel remains 20 to 30% costlier than coal-based methods.
HYBRIT’s advancements position it as a global blueprint for decarbonizing heavy industry, with scalable solutions that are now transitioning from pilot to commercial reality. This includes the viability of hydrogen storage in subsurface caverns with respect to other hydrogen applications. Meanwhile, this project demonstrates that hydrogen-based steelmaking is technically viable, could become economically feasible, and is environmentally transformative.