Hydrogen blends could cut direct ironmaking emissions by two-thirds
A recent simulation study conducted by researchers at Åbo Akademi University indicates that increasing the proportion of hydrogen in the fuel mix for direct ironmaking could reduce direct carbon dioxide emissions by approximately two-thirds. The study, which was first published online in the journal Fuel on 3 March 2026 and assigned to the 15 September 2026 issue, models a gradual transition from natural gas to hydrogen-rich feeds. The findings suggest that this shift can be achieved while keeping a key measure of iron quality, known as metallization, above 90 percent. This research provides a technical pathway for decarbonizing a critical stage of steel production, although it does not account for the emissions associated with hydrogen production or the subsequent steelmaking stage.
The study focuses on Direct Reduced Iron (DRI), a process where oxygen is removed from iron ore while the material remains in a solid state. In conventional setups, hot gases containing hydrogen and carbon monoxide perform this reduction inside a shaft furnace. The resulting iron product can then be fed into an electric arc furnace, which uses electricity to melt the material for final steel production. By modeling the interaction between the furnace and a gas reformer, the Finnish team explored how varying the input of hydrogen and methane affects both emission levels and product quality.
What Changed in the Simulation
The core of the Åbo Akademi University study lies in its examination of a gradual transition strategy. Rather than assuming an immediate switch to 100 percent hydrogen, the researchers modeled a scenario where the share of hydrogen in the fresh hydrogen-and-methane feed increases from 10 percent to 90 percent. This incremental approach reflects the reality that many industrial facilities may not be able to switch fuel sources overnight due to infrastructure, cost, or supply constraints.
The simulation estimates that raising the hydrogen share to this level cuts direct CO₂ emissions from the ironmaking system by about two-thirds. This reduction is significant because it demonstrates that substantial emission savings are possible even before the entire process is fully decarbonized. The study also highlights that this emission saving is achieved while maintaining a metallization rate above 90 percent. Metallization measures the share of the iron content in the ore that is converted into metallic iron. According to Midrex, a company involved in DRI technology, metallization is a percentage of the total iron content, not a measure of everything in the final product. Maintaining high metallization is crucial for the efficiency of downstream electric arc furnaces, as it reduces the amount of energy required to melt the material.
The team modeled the furnace alongside a gas reformer, which converts methane and steam into hydrogen-rich gas. This setup is typical for facilities that are transitioning from natural gas, as it allows for the co-processing of fossil fuels and hydrogen. The study also examined the recycling of gas that leaves the furnace. The researchers found that increasing the amount of recycled gas improved iron reduction but could reduce methane conversion in the reformer. This trade-off is an important technical detail for engineers designing hybrid systems, as it suggests that optimizing gas recycling requires balancing multiple variables to achieve both high quality and low emissions.
Technical and Business Explanation
To understand why hydrogen is central to this transition, it is helpful to look at the chemistry involved. Hydrogen removes oxygen from iron ore by forming water. In contrast, carbon monoxide, which is produced from natural gas, forms carbon dioxide when it removes oxygen. Therefore, replacing carbon monoxide with hydrogen directly reduces the amount of CO₂ released during the reduction process. The simulation shows that as the hydrogen share increases, the direct emissions from the furnace decrease proportionally.
However, the study explicitly excludes the emissions associated with producing the hydrogen itself. This is a critical limitation. The wider emissions footprint of hydrogen depends entirely on how it is produced. Green hydrogen, which is produced using renewable electricity to split water, has a much lower carbon footprint than hydrogen produced from natural gas. But supplying the renewable electricity and operating the production equipment still carries costs and environmental impacts. The study’s findings are therefore best understood as a measure of the direct process emissions, not the total lifecycle emissions of the steel produced.
From a business perspective, the cost of hydrogen remains a major constraint. The International Energy Agency (IEA) provided context in its 2025 assessment, estimating that early commercial steel plants using fully hydrogen-based direct reduction and electric arc furnaces faced production costs 50 percent to 140 percent above conventional blast furnace-based plants. These estimates were based on 2024 energy prices and excluded explicit subsidies or carbon-pricing support. This cost gap is a significant barrier to adoption, as steelmakers operate in a highly competitive global market where price is a key factor.
Key Benefits and Implications
The primary benefit of the hydrogen blend approach is the substantial reduction in direct emissions. A two-thirds cut in CO₂ from the ironmaking stage is a significant step toward decarbonizing the steel industry, which is one of the largest sources of industrial emissions globally. The fact that this reduction can be achieved while maintaining high iron quality is a major advantage. It means that steelmakers do not have to sacrifice product performance to reduce their environmental impact.
The gradual transition model also offers a practical pathway for existing facilities. Many steel plants are currently using natural gas for DRI production. By increasing the hydrogen share incrementally, these plants can reduce emissions over time without requiring a complete overhaul of their infrastructure. This phased approach may be more feasible for companies that are not yet ready to commit to fully hydrogen-based systems.
Furthermore, the study highlights the importance of gas recycling in optimizing the process. By understanding how recycling affects both iron reduction and methane conversion, engineers can design systems that maximize efficiency and minimize waste. This technical insight could lead to more effective hybrid systems that balance cost, quality, and emissions.
Risks and Limitations
Despite the promising results, there are several risks and limitations to consider. First, the simulation is not evidence that a commercial plant has achieved the two-thirds saving. The findings are based on a model, and real-world conditions may differ due to factors such as equipment variability, maintenance, and operational practices. The proposed hydrogen-rich operating conditions still require industrial assessment to confirm their feasibility and effectiveness in a commercial setting.
Second, the cost of hydrogen remains a significant barrier. The IEA’s estimate of 50 to 140 percent higher production costs for fully hydrogen-based plants underscores the financial challenge. Without subsidies or carbon pricing, it may be difficult for steelmakers to justify the investment in hydrogen infrastructure. The cost of renewable electricity, which is needed to produce green hydrogen, also plays a role. If renewable energy prices remain high, the cost of green hydrogen will also be high, further widening the cost gap with conventional methods.
Third, the study excludes the emissions from hydrogen production. If the hydrogen is produced from fossil fuels, the overall carbon footprint of the steel may not be significantly lower than that of conventional blast furnace-based production. Therefore, the environmental benefit of the hydrogen blend approach depends heavily on the source of the hydrogen. Steelmakers will need to ensure that they are using green hydrogen to achieve meaningful emission reductions.
Finally, the study does not account for the subsequent steelmaking stage. The electric arc furnace, which melts the DRI, also has its own emissions profile, depending on the source of electricity. A comprehensive assessment of the steel’s carbon footprint would need to include emissions from both the ironmaking and steelmaking stages.
Sector Impact and Business Implications
The findings of this study have significant implications for the steel industry. As governments and consumers increasingly demand lower-carbon products, steelmakers will need to find ways to reduce their emissions without compromising competitiveness. The hydrogen blend approach offers a viable pathway, but it requires significant investment in hydrogen infrastructure and a reliable supply of green hydrogen.
For steelmakers, the key challenge will be to secure a cost-effective supply of green hydrogen. This may involve long-term contracts with renewable energy producers or investing in on-site hydrogen production. The IEA noted that many projects capable of near-zero-emissions iron production planned to start with natural gas, with unclear deadlines for switching. This suggests that the transition to hydrogen will be gradual, and steelmakers will need to plan for a long-term shift in their fuel mix.
The study also highlights the importance of collaboration between steelmakers, hydrogen producers, and policymakers. To accelerate the transition, there needs to be a coordinated effort to reduce the cost of green hydrogen and to create a market for low-carbon steel. This may involve government incentives, such as subsidies or carbon taxes, to make low-carbon steel more competitive with conventional steel.
Who May Be Affected
Several stakeholders are likely to be affected by the transition to hydrogen-based ironmaking. Steelmakers will need to invest in new equipment and processes, which could be costly but may also provide a competitive advantage in the long run. Hydrogen producers will see increased demand for green hydrogen, which could drive growth in the renewable energy sector. Consumers may see higher prices for low-carbon steel in the short term, but this could be offset by the environmental benefits and potential government incentives.
Policymakers will need to create a regulatory environment that supports the transition to low-carbon steel. This may involve setting emission standards, providing financial incentives, and investing in hydrogen infrastructure. The success of the transition will depend on the ability of these stakeholders to work together to overcome the technical and economic challenges.
What to Watch Next
As the steel industry continues to explore ways to reduce its carbon footprint, several developments will be worth watching. First, the results of industrial assessments of hydrogen-rich operating conditions will be crucial in determining the feasibility of the approach. If commercial plants are able to achieve the emission reductions predicted by the simulation, it will provide strong evidence for the viability of hydrogen blends.
Second, the cost of green hydrogen will be a key factor. As renewable energy costs continue to fall, the cost of green hydrogen is expected to decrease as well. This could make hydrogen-based ironmaking more competitive with conventional methods. The IEA’s 2025 assessment used 2024 energy prices, so future estimates may show a narrower cost gap.
Third, the development of hydrogen infrastructure will be essential. The production, storage, and transport of hydrogen require significant investment in new infrastructure. Governments and private companies will need to work together to build this infrastructure to support the transition to low-carbon steel.
Finally, the role of carbon pricing and subsidies will be important. If carbon prices rise, the cost of conventional blast furnace-based production will increase, making low-carbon steel more competitive. Conversely, if subsidies for green hydrogen are reduced, the cost of hydrogen-based ironmaking may increase. The policy environment will play a crucial role in determining the pace of the transition.
In conclusion, the Åbo Akademi University study provides valuable insights into the potential of hydrogen blends to reduce direct ironmaking emissions. While there are significant challenges to overcome, the findings suggest that a gradual transition to hydrogen-rich feeds is a viable pathway for decarbonizing the steel industry. As the industry continues to evolve, it will be important to monitor the technical, economic, and policy developments that will shape the future of low-carbon steel.