Green steel: what it is, how it's produced, and how much it pollutes.

The steel industry is one of the most polluting in the world. It produces between 7 and 9 percent of global CO2 emissions—the same amount of pollution as Japan and India combined. However, technology has made significant progress, and alongside traditional steel, green steel is now being produced, with a significantly lower environmental impact.

GREEN STEEL

Green steel, also known as green steel, is a sustainable alternative to conventional steel, the production of which releases extremely high amounts of CO2. To make it green, it's necessary to focus on sustainable production processes, which several companies are already pioneering by using hydrogen as an energy carrier. This significantly reduces polluting emissions because hydrogen, which can be extracted from water, releases primarily water vapor. Unfortunately, there are some disadvantages: the main one is that this type of production is very expensive.

Another alternative to traditional steel is the production of steel from recycled ferrous scrap , which reduces waste and requires only carburization in an electric furnace. Producing steel from scrap instead of virgin ore reduces energy input by 75 percent and saves 90 percent on raw material costs.

HOW IT IS PRODUCED

Steel production begins with a series of iron ores that are transformed into metals through a reaction with carbon monoxide, produced by burning coke. The production process typically requires very high temperatures, sometimes exceeding 1000 degrees Celsius, after which the material is cooled. The pig iron is then transformed into steel. Both of these production steps produce enormous amounts of CO2.

What's the difference with green steel? Companies opting for sustainable production are experimenting with various ways to reduce CO2 emissions, replacing the carbon monoxide normally used with other gases with a lower environmental impact, such as hydrogen. Another approach is to produce steel from recycled ferrous materials.

HOW MUCH DOES IT MAKE?

The problem with green steel produced using hydrogen is that, without carbon , the material could be less ductile and versatile. This is why many companies are looking at alternative solutions, such as the aforementioned recycling of ferrous scrap. Another problem is the intermittent production of green hydrogen.

WHERE IT IS PRODUCED

Green steel is produced by numerous companies around the world: the world's first hydrogen steelworks opened in Switzerland in 2018, and a similar plant opened in Austria in 2021 and currently produces approximately 250 tons of green steel annually. H2 Green Steel also produces sustainable steel in the Swedish town of Boden, and in Finland, Blastr Green Steel has been commissioned to build a green steelworks in the municipality of Inkoo. Blastr's goal is to reduce emissions by 95%.

In Italy, the Bergamo-based company Acciaitubi SpA is responsible for the production of green steel pipes . The Abs steelworks in Cargnacco is also moving in the same direction, and green steel production is expected to begin in 2024.

Italy is the country that produces the most steel obtained from recycled scrap metal.

GREEN STEEL EMISSIONS

While the steel sector typically produces around 2,6 million tonnes of CO2 per year, equivalent to 7-9% of total global emissions, using green hydrogen can reduce emissions by up to 90%.

WHY DOES STEEL RUST?

Steel rusts because it contains iron: rust attacks iron in particularly humid conditions due to the action of oxygen. Rust also attacks steel when the iron it contains is exposed to oxygen, water, or a variety of corrosive agents for prolonged periods.

OTHER CURIOSITIES AND USES OF STEEL:

• Recycled steel: a solution to saving energy and raw materials
• How to clean steel surfaces