Humans have been making steel for more than two millennia. In its modern form and scale though, steel is responsible for a significant portion of annual carbon dioxide emissions. The whole industry will need to adopt a range of technologies and practices to reduce its negative impact, and steel recycling companies are helping to lead the way.
It’s history lesson time in ye olde favorite environmental blog (probably not your favorite, but please let me live on in bliss). This time, I’m going to write more than you care about one of the most important industries on earth - steel. Trust me, this one is going to be a slag, I mean slog, so consider grabbing a drink at the (re)bar before settling in. As far as industries go, it’s a dirty one, so I’ll need to put some lipstick on this pig iron. Though you’ll feel like you’ve been through a crucible when I finish, I hope you’ll come out smarter. Okay, I need to stop with the puns if I want to keep my reputation stainless.
Steel Through the Ages
Let’s start by saying exactly what steel is. It’s an alloy of iron and carbon, with the carbon only making up between 0.002% and 2.14% of the steel by weight. By adding this little bit of carbon to iron, steel becomes harder, stronger, and rust resistant compared to pure iron. By adding other elements to the mix, like chromium, vanadium, tungsten, cobalt or nickel, we can make a variety of steel alloys with various physical properties. See? Science is cool.
But on to the history. Humans began replacing bronze with iron in their weapon and toolmaking in the Middle East and southeastern Europe about 1200 BCE. From the beginning of the Iron Age, there was evidence of steel, but likely more out of accident than intentionality. In the 500s BCE, the Tamil people in India developed a method of smelting ore with charcoal that was called wootz steel, which when fabricated into tools has patterns of flowing bands. The Chinese adopted this methodology a few centuries later and began producing large quantities of steel. Wootz steel would remain the primary form of steel production for a long time, even serving as a primary component of Damascus steel, which dates back to the 11th Century.
In the 1700s, various inventions and practices advanced the steel trade, including the use of coke in smelting, the use of steam power, and the development of the steel roller. The big pivot came in the 1850s though. An English fellow by the name of Henry Bessemer patented a process that would blow air through molten iron, causing oxidation that would remove impurities from the base iron. Carbon could then be added back, resulting in a high-quality steel capable of mass production. A similar method, called open hearth steelmaking, improved on Bessemer’s design soon after. The steel industry took off throughout Europe, and in the United States it was Andrew Carnegie who would build an economic empire.
Finally, in the decades following World War II, steelmaking was fully modernized through the development of basic oxygen steelmaking (which blew pure oxygen through molten iron instead of ambient air) and electric arc furnaces (which utilize electricity to generate the heat for steelmaking). Today, it’s a fully ubiquitous material used all over the world.
The Carbon Emissions Associated with Steel
But…steelmaking has a carbon problem. Sure, carbon is an essential element in the fabrication of steel, but carbon emissions are a troubling byproduct of this massive industry. According to the International Energy Agency (IEA)
, the direct carbon intensity of steelmaking in 2021 was 1.39 tons of carbon dioxide per ton of steel. That is driven by the fact that making steel requires A LOT of energy. Today, much of that energy comes from the burning of coal, producing excessively high amounts of carbon dioxide emissions.
When you sum that up globally, the numbers are staggering. The IEA tracks that too
, and in 2021, global crude steel production totaled 1.952 billion tons. With a carbon intensity of 1.39 per ton, that yields a 2021 footprint from steel of 2.71 billion tons of carbon dioxide. Global carbon emissions
totaled 37.12 billion tons in 2021, meaning direct emissions from steel production accounted for 7.3% of global emissions. When you account for indirect emissions, like those from mining iron and transporting finished steel around the world, the number would only rise.
According to a Wood Mackenzie report from last year
, the path to net-zero steel production will require between $1.3 and $1.4 trillion by 2050. Those investments will need to take place across the entire production chain, from mining through fabrication through capturing the carbon produced in the process. Steel will also have to embrace renewable energy and invest in forms of green hydrogen. It’s a steep slope ahead.
A Leading Company in Steel Recycling
I have good news though! The steel industry knows it has a problem, and there are signs it is working to address it. The World Steel Association is publicly supportive of the Paris Climate Accord
, and they encourage members to adopt a variety of low-carbon steel processes. Moreover, one of the most important solutions for decarbonizing steel is a full embrace of recycling as a practice. That’s one of the advantages for steel - steel is infinitely recyclable, unlike plastic for instance.
In fact, in Corporate Knights’ newly released Global 100
, an annual report of the top 100 most sustainable public companies, a steel company leaped to the top spot. Schnitzer Steel Industries Inc., based in Portland, Oregon, is a leading company in steel recycling. From their website
, “By recycling metals, we are diverting and reusing millions of tons of materials each year that might otherwise be destined for landfills. The ferrous and nonferrous metals we process are utilized to manufacture new metal-based products, conserving natural resources and significantly reducing greenhouse gas emissions….Our facilities are powered by 100% net carbon-free sourced electricity, our finished steel products are made of 95% recycled content, and we recycle and reuse 88% of our total water withdrawal.”
I’m impressed by those numbers, and they show what is possible in such a polluting industry. Steel has come a long way, but it has a long way yet to go. With companies like Schnitzer Steel leading the way, I’m hopeful that steel will be at the leading edge of decarbonizing our economy.