Zero CO2 Steel by Molten Oxide Electrolysis: A Path to 100% Global Steel Decarbonization

Iron and steel production is one of the largest global energy consumers in the manufacturing sector and generates over 8% of global carbon dioxide (CO₂) emissions. Steel has also been one of the most difficult industries to decarbonize—as the dominant production method, blast furnace and basic oxygen furnace (BF-BOF), is fueled mainly by coal. Technologies such as carbon capture and sequestration (CCS), natural gas-based direct reduced iron (NG-DRI), and hydrogen-based direct reduced iron (H₂-DRI) offer alternatives to coal-powered steel production and have the potential to reduce greenhouse gas emissions in the steel industry. However, these technologies have significant limitations in that they: (i) offer only incremental improvements in process emissions; (ii) can only address a small portion of the market; (iii) have structural cost disadvantages over traditional steel production; or (iv) are dependent on limited global supply chains for critical feedstock. Boston Metal has developed a technology called molten oxide electrolysis (MOE) that circumvents all of these limitations. The MOE process uses renewable electricity to convert crude iron ore directly into high-purity molten iron. This one step process avoids CO₂ emissions from primary steel production and does not generate waste, offering a simple, scalable, and truly decarbonized solution.

To accelerate the transition to a zero-emission economy, the United States must invest in technologies that can achieve long-term impact through full decarbonization of “hard to abate” industrial sectors. This requires a fundamental shift in sourcing and processing within the global steel industry where an ideal technology would be:

1. A truly CO₂ emissions-free process;
2. Able to use 100% of globally available iron ore feedstock;
3. Cost-competitive without long-term subsidies or regulatory pressures; and
4. Capable of global deployment through a modular, incrementally scalable pathway.

In addition to true global decarbonization potential, emerging steel technologies must enable key domestic policy objectives, including maintaining high levels of resource efficiency, strengthening supply chain resilience, and sustaining future generations through regional economic and environmental impacts.

Boston Metal’s MOE process meets all the technical decarbonization requirements and can strengthen domestic policy priorities. At full production scale, MOE has the potential to provide steel at a cost around 15% below today’s global coal-based steel by simplifying multiple steps into one. Like aluminum smelting, MOE runs in modular reactors and can be economically scaled in steps of less than 100,000 tons/year of production capacity. This reduces the financial barrier to adopting MOE and provides maximum deployment flexibility that caters to all sized organizations as an additional revenue stream to mini-mills using Electric Arc Furnaces (EAF) through large steel producers. Since MOE adoption will be driven by simplicity, environmental benefits, lower cost, and a growing demand for green steel, it will be insulated from future changes in political priorities and international events and is the only technology that can meet 100% of the global steel production demand with emissions-free iron.

Global Decarbonization Requirements Comparison: MOE vs. Alternative Technologies

Requirement #1: Be a truly CO₂ emissions-free process – To abate 100% of global steel emissions, the process used to produce iron must not generate CO₂ emissions. While technologies like NG-DRI and CCS reduce emissions significantly (~30% and 80% compared to coal-processes, respectively), they are insufficient to reach 100% global decarbonization. MOE is a zero-CO₂ emission process that uses direct electrolysis of iron oxide to produce high-purity iron plus oxygen, enabling full global decarbonization of the steel industry.

Requirement #2: Be able to use 100% of globally available iron ore feedstock – Today’s coal-based steel production uses the full range of traded iron ore grades. To serve the entire global market, any technology must be able to use the same range of feedstocks. Processes like NG-DRI-EAF and H₂-DRI-EAF are limited to only high-purity premium iron ore feedstock (~3% of global iron ore supply), severely limiting the total fraction of the global market they can address with an extremely high-cost input. Conversely, technologies like BF-BOF with CCS can use all grades of ore but do not fundamentally eliminate CO₂ emissions (Requirement #1).  Iron production using MOE can use all traded ore qualities (demonstrated with purity less than 58% iron), ensuring that this technology that has the potential to serve the entire global steel market.

Requirement #3: Be cost-competitive without subsidies – While the United States is currently in a political climate that strongly encourages industries to decarbonize, this may not always be the case.  As such, investments by the government today should focus on those technologies that have the potential to be cost-competitive, long-term solutions without subsidies or other regulatory pressure relative to the incumbent coal-based processes.  For example, while there will continue to be improvements in the cost of CCS, it will always be a cost-adder on top of the price of steel (~25% increase to levelized cost of steel), and will never compete on cost in the absence of subsidies. NG-DRI and H₂-DRI are more cost-competitive but are still more expensive than coal-based steel; incurring a green premium that will limit widespread adoption. A simplified MOE process reduces the energy and environmental burden of steelmaking by reducing the incumbent multi-step process to a single step. This process can minimize energy inputs, improve process efficiencies, and reduce the physical footprint required for steel production. As such, MOE is projected to be ~15% lower cost than coal-based steel without subsidies. Investment to transition MOE into commercial production will create a long-term decarbonization solution that will continue to grow in market share based on commercial drivers, enabling the transition to 100% global decarbonization regardless of future events.

Requirement #4:  Be capable of global deployment through a modular, incrementally scalable pathway – The steel industry is extremely conservative due to historically low profit margins, long investment cycles, capital-intensive infrastructure, and competition from unregulated international markets. This makes it very difficult to get this industry to invest in new technologies that require megaton-scale to be cost-competitive, such as H₂-DRI and CCS. MOE uses a modular reactor design, similar to that used for aluminum smelting, which can be deployed in increments of less than 100,000 tons/year. This minimizes the barrier to adoption and enables MOE to serve the entire market when each organization is ready to transition as expanded capacity and even retrofits in existing primary and secondary steelmaking facilities across the U.S., as well as new MOE plant construction at >1Mton scale.

Domestic Policy Priorities: The administration has made it clear that economic and environmental benefits have become table stakes. As we build towards our net zero future, public funding will prioritize technologies that are the most efficient use of our limited resources, can strengthen domestic supply chains, and are enabled through community sustaining jobs. MOE converts crude iron ore into pure molten iron and oxygen, with the remaining material being a drop-in replacement for the construction industry. This process has full resource utilization, resulting in zero waste, and will provide positive community benefits through scalable iron production capacity with high quality jobs.  Boston Metal’s MOE is well positioned to deploy across the U.S., bringing demand for renewable energy while offering a distributed, highly efficient technology and revenue stream to large and small regions alike.

MOE Requires Demonstration at Commercial Scale to Drive Industry Investment

Boston Metal’s MOE technology is at an inflection point in its technical validation and subsequent scaling. Through a combination of public and private investment, Boston Metal has validated MOE to the industrial scale. However, MOE must be demonstrated at full manufacturing scale, with the complexity of the real world, before the steel industry will begin to invest in global deployment. The steel industry is very conservative in adopting new technology, due to the very high cost of new manufacturing plants (multiple $ billions) and the narrow margins of this commodity product. If we wait for the steel industry to drive MOE forward on its own, it could take a decade or more to reach commercial deployment. By co-investing with industry stakeholders in the first full-scale demonstration of MOE, the DOE will enable the commercialization of this technology within the next three years with a fully domestic supply chain.