Lighten up: Primary steel production is responsible for up to 9 percent of CO2 emissions

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This website has written often about the CO2 emissions from the manufacture of cement and also from aluminum, but have rarely mentioned iron and steel. That’s because the industry has made dramatic changes over the years, and recycles 86 percent of scrap into useable steel in electric arc furnaces, producing far less CO2 and other pollutants than production of new steel from iron ore. (just look at these photos of Pittsburgh from back in the day).

But as with aluminum, demand for new steel far exceeds supply of recycled steel, so there are still steelworks all over the world that make primary steel in basic oxygen furnaces, where steelmakers blow oxygen through molten iron, reducing carbon content by turning it into CO2. This is after melting the iron with coke, made from coal heated in the absence of air. A ton of steel is made from 2500 pounds of iron ore, 1400 pounds of coal and 120 pounds of limestone.

So much primary steel is made that in fact, worldwide, iron and steel production are responsible for 7 to 9 percent of all direct emissions from fossil fuels. Just counting industrial emissions, iron and steel are 24 percent; cement is less, at 18 percent, plastic at 6 percent.

According to Michael Pooler in the Financial Times, there are technologies that can reduce the carbon footprint of steel, but not much is actually happening to implement them.

As a basic material central to the modern economy, which is also the most traded commodity after oil, perhaps the greatest challenge is to deliver so-called green steel at a competitive price.

“In principle there are technology routes to lower emissions from steelmaking,” said David Clarke, head of strategy and chief technology officer at ArcelorMittal, the world’s largest producer by tonnage. The catch, he added, was that “society would have to accept higher costs of steel production”.

In a circular economy, demand should equal supply of recycled steel

The steel industry tells a wonderful story about recycling and does a great job. But if we are going to get a handle on our CO2 production we have to reduce primary steel consumption. In fact, we should be aiming for a circular economy where we reduce demand to the point where we can almost eliminate the need for primary production other than that which is needed for specialty steels.

So we have to ask, why do cars keep getting bigger and heavier? Why to buildings keep getting taller and skinnier, using more steel per square foot of usable space? Why is nobody talking about this?

We have noted before how Bucky Fuller once asked Norman Foster “How much does your house weigh?” I recently asked “how much does your car weigh?” And that was before learning about the huge carbon footprint of primary steel production. Every ton matters.

Lighten up: Primary steel production is responsible for up to 9 percent of CO2 emissions

We have to use less of the stuff in our cars, our buildings and our infrastructure.





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