Many industries and manufacturers are seeking a path to carbon neutrality. One of the largest players is up to bat. Steel. Innovators are on a mission to decarbonize steel.

Enter one of the latest buzz terms in carbon neutrality: green steel.

But just how green is it? Better yet, what is it?

Turns out there isn’t an easy answer. A quick search on Google brings a variety of results that might not match up or make a lot of sense to a beginner.

You’ll read about H2 green steel and fossil-free manufacturing in Sweden, clean electricity, and electric arc furnaces. Search Wikipedia and you’ll read about steel manufactured by burning old rubber tires. You might even take a left turn and find yourself scanning an article about green steel kitchen mixing bowls! Who can make sense of all this?

Amidst the confusion, commodity price reporting agency Fastmarkets absolutely nails it.

“Green steel is simply steel with the lowest carbon footprint currently possible, which will vary from producer to producer and will continue to evolve over time.”

There are a lot of ideas and innovations aimed at achieving this by making the industry more sustainable through emissions-reduction techniques.

The problem with steel

Steel is one of the most important materials in modern infrastructures. It’s everywhere: buildings, ships, airplanes, cars, hospitals, etc.

It is the second largest industry in the world, behind only oil and gas. There were nearly 2,000 megatons (MT) produced in 2020 alone, making it one of the most heavily produced substances on earth.

That figure is expected to increase by 25% to 30% by 2050, according to MDPI.

But here’s the problem.

Its production is heavily reliant on coal and steel accounts for 7% to 9% of all CO2 emissions. This isn’t great news for global warming.

Enter the green steel movement! Innovators have been working on sustainable production techniques for several decades.

Sustainability from burning old tires

One of the first times the term green steel popped up came from the pioneering work of University of New South Wales professor, Veena Sahajwalla, who was dubbed “the first lady of green steel” by the Waste Management Review.

Understanding why burning tires to make steel is a good idea requires some insight into the production process.

Making steel involves using giant blast furnaces to superheat iron ore and carbon in the form of coal above 1500 °C. To put it into perspective, this is hotter than the eruption temperature of lava!

Carbon is an important part of the process. It eliminates oxygen from iron in a chemical process known as reduction, which generates a lot of CO2

Here’s where tires come in.

Sahajwalla realized there was another cheap and readily available source of carbon other than coal that could produce the same result: old car tires.

While seemingly counterintuitive for reducing emissions, burning them is ideal for a couple of reasons.

First, it avoids mining additional resources and creates a use for burdensome waste. Also, tires are rich in polymer, which is great for the reduction process. Another benefit is that they can produce hydrogen, which can be turned into a liquid or gas.

Admittedly, burning old rubber isn’t the first thing that comes to mind when we think of green technology. More and more, green steel is thought of as a zero-carbon innovation. While the idea that an energy-intensive process can be emissions-free is partially a fantasy, some innovators are taking it to the next level.

Fossil fuel free steel from hydrogen

Another innovator in America has come up with a completely different method for cleaning up steel.

Boston metal is looking to leave hydrogen out of the equation altogether. It’s developed a process called molten oxide electrolysis, which removes oxygen from iron ore using electricity.

It works like this.

Iron ore is fed into a chamber, which is then filled with a liquid oxide electrolyte. Then an electric current runs through the chamber, superheating the ore into molten iron and oxygen. Presto! The ore has undergone reduction.

Bypassing the hydrogen step increases the overall efficiency of the process, even though it requires higher temperatures than hydrogen-based manufacturing.

A study by Columbia University recognized electrification as the key to reducing emissions in the steel industry.

This is where things get tricky!

How green is green steel?

While electrification on its surface seems cleaner than throwing a bunch of coal into a blast furnace, there is something important to consider. Namely, the source of the electricity.

The methods described above took great pains to use clean electric sources. But overhauling an industry as massive as steel with electricity might not be so simple. Here’s why.

In the E.U., more than 40% of electricity generation comes from fossil fuels. In China, it rises to about 47%. The U.S. electrical grid depends on combustible sources to generate a whopping 61% of its power. Excluding nuclear power, only the E.U. cracks 30% generation from renewable sources.

So, if you’re using electricity that comes from a coal power plant in order to eliminate carbon dioxide emissions, the effect is neutralized.

If electrification is a key step towards sustainability, the source green steel technologies rely on should be scrutinized.

Challenges for transformation

Making green steel is about 25% more expensive than conventional methods, according to RMI, a climate think tank. This makes it easier for buyers to turn it down for traditional steel.

It all comes down to how much consumers are willing to pay for the price of going green.

Another caveat with making steel from hydrogen is that it requires an extremely high-grade ore, which is not used across the industry. Efforts are ongoing to develop ways to use lower grades with hydrogen techniques.

The sheer size of the steel industry is also daunting. Time Magazine points out that if SSAB decarbonized all of its furnaces and produced only carbon-free steel, the amount would represent under half a percent of the world’s annual production.

Despite the difficulties, there are more than 55 steel decarbonisation projects around the world in 19 countries. That number will continue to grow.

There is a broad recognition that the high CO2 emissions the industry produces represent a significant opportunity to move toward carbon neutrality as countries are scrambling to meet carbon neutrality goals by 2050.

Expect more green steel initiatives in the future.  

Which industries do you think should be decarbonized? FUSO GreenLab is looking for opportunities to introduce decarbonizing solutions to manufacturing. We’re looking for innovators to help us with this process. We would love to hear from you!