Green steel carbon categorization | Nexigen®

Steel categorization


The term “green steel” has been thrown around in our industry for a while now. But taking a closer look quickly reveals that there is no universal definition for green steel. Currently, the term is used to describe steel that is produced in a CO2-reduced manner. A similar situation can be observed with certificates and labels. Several producers are starting to have their steel certified as “green.” However, these certificates vary widely so that it becomes difficult for customers to compare.

We have eliminated that problem by developing a categorization that is based on customer demand, steel producer perspectives, steel production technology routes and the GHG Protocol as the leading carbon accounting standard. At the same time, we are convinced that apart from the full elimination of CO2 emissions already substantial reduction adds value along the way of the green transformation. Therefore, our categorization includes several CO2 reduction levels.


Nexigen® steel categorization



Emission in kg CO₂/ t Steel

Emissions in kg CO2/t steel


How our categorization works


We divide CO2-reduced steel products into five categories based on the product’s actual carbon footprint from resource extraction and production to the point where they leave our warehouse. They range from START (with a footprint from 1,750 to 1,400 kg CO2 per metric ton) to PRIME (400 to 0 kg CO2 per metric ton).

BALANCED is a separate category for “reduced balance” steel products. Depending on the raw materials and energy sources used, products manufactured within the same production facility may have different carbon footprints. Balancing involves first taking the facility’s total CO2 emissions into account and then calculating the average carbon emissions per metric ton of the manufactured product. Reduced emissions are thus allocated to limited volumes, which reduces the carbon footprint balance. These steel products fall within our BALANCED category.

✓ Methodology based on international standards
Our calculation methodology follows the internationally renowned GHG Protocol.

✓ All emissions from resource extraction and production to the point where they leave our warehouse are included
Emission ratings include production (Scope 1), purchased power (Scope 2) & supply chain (Scope 3 Upstream).

✓ No offsetting is included in CO₂ load categorization
The physical production emissions determine the product’s categorization; CO2-offsetting is not included.


More background information on steel

Blast Furnace (BF BOF)

Iron ore pellets and sinter feed are the iron-bearing raw materials. Coke from metallurgical coal is the main energy source. These elements and limestone are fed into the blast oven furnace from the top, while hot air is blasted from the bottom. The burning coke creates temperatures of ~2,000 °C, extracting hot metal (pig iron) from the raw material. The hot metal is transformed into steel through oxidation in a basic oxygen furnace (BOF). Often some scrap is added. The resulting liquid steel is then cast.

Electric Arc Furnace (EAF)

Most EAF mills use scrap as their main input. In regions with competitive gas prices, direct reduced iron (DRI) may also be used. For direct reduced iron, iron ore and pellets can be reduced in a solid state for use in the EAF. Natural gas is typically used as a reductant. Scrap or direct reduced iron is melted in an EAF at around 3,000 °C. Graphite electrodes function as an arc to transform the electrical energy into heat.

Direct Reduced Iron EAF

The future of steel is green – and there are two possible ways to get to green steel production. The first is steel from EAF production that uses 100% scrap and is powered with renewable energy. Given the finite amount of scrap, green steel production via this route is naturally limited. The second way is using green H2 as the reductant for direct reduced iron in an electric arc furnace pathway (see electric arc furnace). Beyond that, other alternatives for sustainable iron reduction are also being developed. 

Due to its durability and low maintenance frequency, steel is one of the most preferred materials across the globe – be it for construction, the automotive industry or ship building. Compared to other materials such as concrete or timber, however, there is another major advantage that will become even more important in the future: Steel recycling can be repeated an infinite number of times without any loss of quality.

The great material properties as well as the opportunities of steel recycling reinforce our conviction:

Steel is not the problem, but part of the solution

Producing steel is often very emissions-intensive. While cutting greenhouse gases such as CO2 thanks to alternative production routes is one way to greener steel, using recycled steel is another. Compared to timber and concrete, the steel recycling quota is very high: 93% of steel can be re-used.

  • LOWER ENERGY USE: Through steel recycling, the steel industry saves enough energy to supply the annual electricity needs of more than 18 million homes
  • LOWER CARBON LOADS: Recycling the steel from one car reduces greenhouse gases equivalent to using more than 550 liters of gasoline


The seven steps of steel recycling





Contact us


If you would like to buy CO2-reduced products from us or learn more about Nexigen®, please send us a message below. We look forward to hearing from you!

Thank you!

Our experts will get in touch with you.


The form couldn't be submitted. Please try again.

Back to form