Some of the steel industry’s most prominent and experienced leaders are at the forefront among those sounding the alarm about their industry: its emissions have more than doubled since 2000, and it must decarbonize significantly — and fast.
Kyung-sik Kim, a longtime senior executive at Korean steelmaker Hyundai Steel, was among the nine global steel experts who recently visited the CBS campus to collectively tackle the urgent question of how best to do just that.
“To see the future of steel, we need to look to the past,” noted Kim, who is now retired from his post at Hyundai Steel and heads South Korea’s Steel Scrap Center. Societies have been making and relying on steel for millennia, he said, and the Industrial Revolution supercharged steel’s usage. Engineering technologies have continuously improved ever since, but there has been one constant throughout: coal, which, mixed with iron ore, produces copious amounts of carbon dioxide (CO2).
“What will happen in the future?” asked Kim, who is also a former committee member of the Second National Master Plan for Energy and a former expert committee member of the National Climate and Environmental Council. “There is one variable that is different from the past: It is carbon dioxide.”
As the world’s climate crisis grows and jurisdictions around the world roll out new climate policies — including direct carbon pricing systems like the European Union’s Carbon Border Adjustment Mechanism (CBAM) targeting CO2 generated outside its borders — the deeply established steel industry will need to transform. And it will have closer to a decade, rather than a century or millennium, to do so this time.
Together, manufacturing sectors account for over 30% of global annual CO2 emissions, and within that broad category, steel is among the top emitters (see graphic below). Though emissions from steelmaking have finally decoupled from production levels as of 2016, demand for steel is rising rapidly — especially in emerging economies. In the absence of major interventions, emissions from steel production will continue to increase.

To limit further temperature increases and forestall the worst effects of climate change, global CO2 and other greenhouse gas emissions must reach net zero. To do so by 2050, iron and steel production must slash emissions by 25% as soon as 2030, according to the International Energy Agency.
The clock is running out. Such a deep and fundamental change to one of society’s most important forms of production ought to warrant decades or more of experimentation and innovation, but the world has waited until close to the final buzzer to act. Steel is considered one of the hardest to abate sectors for a reason: The elegant chemical process that transforms iron ore and coal into iron also happens to release large amounts of carbon dioxide, which is no longer tenable. Now is the moment to make up for lost time.
Insight 1: Multiple technologies for producing lower carbon steel are here — including electrolysis and clean hydrogen — with each presenting its own challenges.

For many years, steelmaking has followed a consistent, two-step process: First, iron ore is mined and mixed with coal, as well as other substances, to make molten iron. This process most often happens using highly polluting blast furnaces. Some 90% of steel-related emissions come from this first iron-producing step.
In the second step, iron is further treated to make steel, to the specifications of the grade of the final product. This can happen via a basic oxygen furnace or a newer, relatively cleaner technology called an electric arc furnace. Today, the cheaper and higher emitting blast furnace/basic oxygen furnace method accounts for nearly three-quarters of global steel production.

New on the scene is hydrogen-powered steelmaking, which keeps this process largely intact, replacing the blast furnace with a direct-reduction reactor and then employing an electric arc furnace for the next step. Because green hydrogen generates water instead of carbon dioxide as a byproduct, steel-producing technologies powered by green hydrogen release roughly 90% fewer carbon emissions than conventional processes.
H2 Green Steel is a Swedish manufacturing startup that expects to begin production on lowcarbon steel powered by green hydrogen as early as 2025. At the CKI workshop, H2 Green Steel’s chief technology officer, Maria Persson Gulda, presented the company’s plans: a green-hydrogen-powered plant set to be built in Boden, in northern Sweden, which the company projects will annually produce 5 million tons of green steel by 2030.
Persson Gulda acknowledged that her company’s steel comes with a price premium of 20% to 30% above the cost of traditional steel. Even so, the company has already signed deals to supply its greener product to IKEA, Mercedes-Benz, and BMW. Persson Gulda explained that as business leaders at these companies and others consider the looming pricing impact of frameworks like CBAM, H2 Green Steel’s current price premium becomes competitive.
She illustrated how her company’s plans have already begun to reshape steel production in certain corners of the industry. When H2 Green Steel announced its plans in February 2021, only about 2 million to 3 million tons of green steel projects were in the works in Europe. Since that time, more than 40 million tons of green steel projects have been slated by 2030.
Representatives of incumbent steelmakers at the workshop also see promise in hydrogenpowered steel. Hyundai Steel’s Kim said he is hopeful about hydrogen as a long-term means toward achieving the company’s goal of carbon neutrality by 2050.
At the same time, Kim voiced concerns about the future global undersupply of green hydrogen — and he wasn’t the only one at the workshop to do so. What’s more, the affordability of using green hydrogen to power steel production, as H2 Green Steel intends to do, is highly dependent on geography, and northern Sweden happens to be one of the only places in the world where it’s economically feasible.
In his presentation, Dan Steingart, a Columbia School of Engineering professor of chemical metallurgy and chemical engineering, pointed out another challenge the hydrogen-powered process presents: It’s less favorable than the traditional process, all the way down to the level of the chemical reaction.
In a blast furnace/basic oxygen furnace, much of the necessary heat is produced by the chemical reactions between iron, oxygen, and carbon inside the vessel. “The chemical reaction does most of the work,” Steingart explained. “You’d have to use significantly more hydrogen as methane in the DRI process to achieve the same effect. And the methane-DRI process is a niche process relative to the dominant coal blast furnace. We can use hydrogen instead of coal, but it’s working at an energy deficit.”
It’s simply for this reason that Steingart waxes poetic about today’s most common form of steelmaking, via the blast furnace, even as he acknowledges the necessity of transforming it for the sake of the climate. “Steel production as it exists is a beautiful thing,” Steingart said. “I find it scary that we can’t use blast furnaces in the sustainable future.”

Over the past four years, Steingart has researched energy storage devices in electrochemical reactors; he also heads the Steingart Lab, which actively studies electrochemical metal production systems. He said he is excited about one specific means of revolutionizing steel production: electrolysis. Steingart served as an advisor and chief scientist for three years at Electra, a Boulder, Colorado-based startup that uses a low-temperature, oxygen-decoupled electrolysis process to make steel. Electra’s CEO and co-founder, Sandeep Nijhawan, also participated in the CKI workshop.
Steingart suggested taking this revolutionary process a step further: It could act just like a battery, he said. In other words, the steelmaking process could conceivably also begin to act as a means of energy storage. “On any given day, in my mythical future, an electrolytic iron operator could decide whether to: a) produce electricity, or b) sell electricity.” he said.
The electrolysis technology that Steingart and Electra’s Nijhawan describe has some additional advantages. It is able to use high-impurity ores and seek out lowest-cost intermittent renewables, lowering operating costs and overall capital intensity of the ore-to-metal value chain, and allowing it to potentially get to cost parity with incumbent fossil-fuel-based approaches.
Insight 2: Steelmakers and sustainability advocates alike must be willing to embrace a ‘messy middle’ as the industry transitions to a decarbonized future.

Steel is an infamously hard-to-abate sector. For one thing, steel production assets have long lifespans before they are due for expensive upgrades. For another, the sector’s energy requirements are massive and will likely tax emerging clean energy systems. Some of these roadblocks can be circumvented — at least for the time being — with an embrace of transitional, “messy middle” technologies and processes, which can represent decarbonization potentials of between 10% and 50% (though they still carry significant green price premiums).
Chris Bataille, an adjunct research fellow at the Columbia School of International and Public Affair’s Center on Global Energy Policy, emphasized at the workshop the variety of options available in moving toward a lower carbon steel industry. In his presentation, he highlighted several pathways to consider, which could be pursued simultaneously, including:
- Designing for material efficiency, which can enable up to a 40% reduction in necessary steel;
- Relying more heavily on recycling scrap steel;
- Implementing a policy push to decarbonize primary iron, which today is commercially possible only through direct reduced iron but could be possible with electrolysis, or;
- Mastery of carbon capture and storage on coal-based furnaces; and
- Installing mechanisms for carbon capture and storage on blast furnaces-basic oxygen furnaces.

“Decarbonization is not about just one technology or one part of the process,” Bataille said.
And yet, even these partial measures present real difficulties, giving many of the workshop participants pause. Take carbon capture and storage (CCS): Bataille acknowledged that the process for capturing emissions at the point of production and storing them still has many technical challenges to be worked out — and in the absence of incentives to invest the time and money to do so, it’s difficult to imagine how the questions will get answered. Bataille estimated that a concentrated effort to solve the riddles presented by CCS will require an investment of roughly $10 billion to $20 billion.
Electra’s Nijhawan predicted that the unanswered questions about the economics of CCS would prevent such technologies from ever playing a major role in steel decarbonization. “The developing world will not adopt anything with a green premium,” Nijhawan said. “That’s a fantasy of the developed world.”
Nijhawan’s point touched on a recurring theme of the workshop discussion: how to decarbonize within emerging markets, where existing steel stock is low but current and projected future production is high. India’s market was frequently referenced among workshop participants, because of the country’s plans to double steel production capacity by 2030. Workshop participants agreed that this production capacity is likely to come via the higher polluting, lower cost blast furnace method.
For this reason, workshop participant Dierk Raabe, director of the Max Planck Institute for Iron Research in Düsseldorf, Germany, insisted, “We should make every effort to make blast furnaces more sustainable.” Specifically, he believes more research is sorely needed to investigate how to lower emissions from blast furnaces without increasing their cost. After all, while blast furnaces may not ever be the fully decarbonized steel solution some holdouts are eager for, they remain a fixture within the sector.
Even the suggestion of cutting carbon emissions by relying more heavily on recycling scrap metal is more complicated than it might seem. While steel is indeed the most recyclable material on the planet, and all participants agreed it’s important to maximize scape use, some offered indications that scrap supplies are becoming restricted. Åsa Ekdahl, head of environment and climate change at the World Steel Association, noted that her organization has seen growing tendencies among some countries to reduce scrap exports. Raabe agreed, predicting that the world has already hit peak scrap availability.
Insight 3: The world needs a consensus definition of green steel (and green iron).
“I think we need a green steel definition,” noted Marie Jaroni, senior vice president of decarbonization and ESG at Germany’s ThyssenKrupp. “Everyone is doing their own thing. It would help our clients and our customers to have one green steel definition, and I think that’s very crucial for all of us.”
She said efforts toward this end are underway in Germany, organized by the German Steel Federation, and other participants pointed to similar moves in the EU and India.
Ekdahl said her organization is closely involved in many of the discussions about landing on a definition of green steel — and from her perch, she can report that the topic is an extremely controversial one. For one thing, there’s no straightforward, technical way to pin down what green should mean; carbon emissions are only one part of the equation.
Jaroni worried that a definition that is too simplistic could penalize pioneers. For example, if a producer were to melt scrap metal, relying on green electricity, the resulting steel would have a very low carbon footprint. However, there’s not enough scrap metal in the world for all producers to follow that strategy. So, who gets credit for doing the hard work of having produced the virgin steel and finding better, if imperfect, methods of doing so?
“Can we define green iron first, before we talk about green steel?” asked Electra’s Nijhawan. “I think it would help simplify the debate we’re having and help create consensus. Iron is the constraint. Iron is iron, and hopefully we can get to that definition easier.”
And for what it’s worth, workshop participants noted, arriving at a consensus definition of clean iron could come with policy benefits for sustainable steelmakers too. Many advocated for a production tax credit (PTC) for green iron, but for that, a clear definition is needed.
“We need to make iron a critical material,” said Nijhawan. “And based on the definition of green iron we decide on, we should put a PTC on it.”

Insight 4: A just transition for steel should include resources for educational and training programs.
“How do you build a just transition into all of this?” asked Columbia SIPA’s Bataille. “You’ve got to involve your communities and local workforces from the beginning and make them part of the solution-finding process.”
Bataille pointed to H2 Green Steel as an example. The startup was very involved from the beginning with local communities near where the new factory is to be built, he said, so there wasn’t a lot of backlash. He suggested that another way to consider community needs is to site any new plants on abandoned, clean brownfields whenever possible.
Global cooperation is necessary in the just transition, too: Bataille recommended that as many early green-steel developments as possible should be in developing countries — to be near the sites of growing demand, drive development, and boost economies. Many of the workshop participants emphasized the need for educational programs to train people in new steel technologies, especially in India and China.
ThyssenKrupp’s Jaroni added that government officials, too, could potentially benefit from education about emerging steel-decarbonization strategies. She believes that education of this type could be a boon to her company as well, as it seeks to transition to new tech and processes, some of which will require approvals from government.
For his part, Raabe, who is a professor at RWTH Aachen in Germany and an honorary professor at the Katholieke Universiteit Leuven in Belgium, is worried that too few young people are opting for educational paths that will prepare them to solve the steel decarbonization problem. Raabe pointed to shrinking classes and departments in metallurgy — and noted that the research literature in an area where it is desperately needed is suffering as a result. He noted that while a search for climate change yielded more than 55,000 papers in 2022, a search for sustainable metallurgy turned up only 110 papers during the same period.
Raabe said his consistent message for young environmental idealists at the cusp of their higher education is, “If you want to solve the decarbonization problem, study metallurgy.”
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