The largest steel buildings in the world are Chicago’s Willis Tower and NYC’s Empire State Building. Together, they represent 138,000 tons of steel, and with 2 billion tons of steel produced a year, that’s enough to copy and paste both skyscrapers more than 7,000 times over… each.
As one of the most common building materials in the world, steel accounts for 10% of global carbon emissions and if it were a country, steel would be the 5th largest emitter, producing 3.2 billion tonnes of CO2 a year. We use so much steel that according to green steel producer, Boston Metal, we could rebuild the Golden Gate Bridge 24,096 times, and use it to wrap halfway around the world.
That’s why Boston Metal is electrifying the primary steel industry with renewables, using a process that completely eliminates the need for coal in steel production.
Coal is the industry’s Achilles’ steel, with about 70% of steel made today made in giant, extremely hot coal-reliant blast furnaces, where purified coal, or “coke,” is heated and melted with iron oxide and limestone. The remaining 30% is made with an electric arc furnace. Using electricity, this process itself does not use coal, but many are reliant on the electricity generated by coal-fired power plants elsewhere in the grid.
Steel production can be traced to at least the 13th century BC when blacksmiths discovered the durability benefits of adding carbon to the welding process. Now, Boston Metal is transforming this age-old technique by heating the all-important iron with electric currents, in a process that completely eliminates the need for coal.
This solution is called molten oxide electrolysis (MOE), and with the zero-emission method, Boston Metal creates what they call, “green steel.” With MOE, Boston Metal is also electrifying the production of high-value metals, such as tin and niobium.
With a $120 million Series C round, announced last Friday, the company hopes to expand its green metals across Massachusetts and beyond. The money will help Boston Metal establish its very first green steel production plant and support the construction and commissioning of a metal manufacturing facility for the company’s Brazilian subsidiary, Boston Metal do Brasil.
The round was led by International steel giant ArcelorMittal, with contributions from Microsoft’s Climate Innovation Fund and SiteGround Capital, bringing the company to $200 million in funding since launching from an MIT lab over a decade ago.
In recent years, major steel manufacturers in the automotive, technology, and construction sectors like Europe’s ArcelorMittal, China’s Baowu Steel, and Japan’s Nippon Steel committed to achieving net-zero targets set by their respective home countries.
However, according to the International Energy Agency’s September 2022 report, the iron and steel industry as a whole is not on track. Between 2020 and 2030, the carbon intensity is only expected to fall by 3% annually. In fact, over the past decade, the CO2 emissions from the subsector have risen due to the increase in steel demand.
The IEA and the Rocky Mountain Institute (RMI) both point out that innovations like carbon capture utilization and storage will help lower the carbon intensity of steelmaking. Still, energy efficiency and electrification processes like hydrogen usage and Boston Metals’ MOE are the best bet at decarbonizing. Scrap-based production can also put a sizable dent in steel emissions. However, because many electrical arc productions already use recycled steel, and scrap supply will increase with steel demand, scrap-based production may be the next hurdle for green steel to conquer.
As of RMI’s 2019 report, hydrogen-based direct reduction is the furthest developed green steel solution. Startups like H2 Green Steel, Electra, Blastr, and SSAB, a joint venture by two of Europe’s largest iron and energy companies, are a part of the hydrogen-based green steel race. Boston Metal may be the only one leading the charge with MOE.
While neither of the options is commercially available at scale yet, Boston Metal says their process is already cost-competitive with traditional steelmaking and is on track to reach commercialization by 2026, one year after SSAB says they will create the world’s first fossil fuel-free steel. Within the next few years, the green steel winner will be crowned.
“Our technology is designed to decarbonize steel production at scale. We believe we have the experienced team, strong financial backing, and the innovative technology required to disrupt the industry,” Tadeu Carneiro, the company’s chairman and CEO said in a statement, adding that ArcelorMittal’s support further reinforces the company's "capacity to lead the green steel revolution.”