Balancing sustainability by reducing CO2 emissions in stainless steel production vital: WSA

World Stainless Association: Stainless steel is an essential material in modern industry, valued for its durability, corrosion resistance, and recyclability. However, increasing emphasis on reducing carbon dioxide (CO2) emissions has drawn attention to the environmental impact of its production. As the global shift toward sustainability intensifies, the stainless steel industry faces the challenge of maintaining its critical role in infrastructure while working to minimise its carbon footprint.

Stainless steel production systems: Scrap-based, NPI-Based

The stainless steel industry operates using two primary production systems: the scrap-based system and the nickel pig iron (NPI)-based system. Each system plays a distinct role in meeting global production demand.

Scrap-based production: This method relies heavily on recycling end-of-life stainless steels and other alloys to create new products. Because it uses recycled materials, it is considered more sustainable of the two processes. This system is common in regions where scrap materials are plentiful. Scrap-based production is aligned with the industry's push toward sustainability due to its lower CO2 emissions.

Nickel pig iron (NPI) production: In contrast, NPI-based production uses nickel extracted from raw ores rather than recycled material. This process is often found in regions where scrap availability is low. While essential to meeting global demand, NPI production results in significantly higher emissions compared to the scrap-based system.

One of the key challenges the industry faces is that the global availability of scrap is insufficient to meet demand solely through recycling. As a result, both production systems must coexist for the foreseeable future.

Quantifying emissions: Scope 1, 2 and 3

To understand the carbon footprint of stainless steel production, the report breaks down CO2 emissions into three categories: scope 1, 2, and 3.

Scope 1 emissions: These are direct emissions from production processes, such as those from fuel combustion. The current average for scrap-based production is 0.41 tonnes (t) of CO2/t of stainless steel. While there has been a slight reduction over time (from 0.43 t in 2012), these emissions remain a significant concern.

Scope 2 emissions: These include indirect emissions from electricity, steam, heating, and cooling used in production. Scrap-based producers have reduced scope 2 emissions to 0.39 t of CO2/t of stainless steel, down from 0.45 t in 2023. This improvement is largely due to changes in regional energy grid mixes.

Scope 3 emissions: Scope 3 emissions are associated with the extraction and transportation of raw materials, including the energy needed for these processes. Emissions vary depending on the amount of recycled content used. For instance, a 50% scrap mix results in 2.9 t of CO2/t of stainless steel. The higher the scrap content, the lower the scope 3 emissions, making recycling crucial to reducing overall emissions.

CO2 emissions over the lifecycle of stainless steel

Stainless steels' environmental impact is not limited to production. The material's long lifespan, recyclability, and low maintenance requirements reduce its overall CO2 emissions over time. For example, in construction, stainless steel structures maintain stable emissions over 110 years, while carbon steel requires regular maintenance to prevent corrosion, resulting in increasing emissions over time. Similarly, stainless steel water bottles, although initially more emission-intensive to produce than plastic, have lower overall emissions due to their durability and ability to be reused for many years.

Moving toward a sustainable future

The stainless steel industry is making significant efforts to reduce its carbon footprint. One of the main strategies is increasing the proportion of scrap used in production. By utilising more recycled material, the industry can significantly lower scope 3 emissions. Additionally, improvements in energy efficiency and advancements in greener technologies for NPI production are expected to further reduce emissions in the coming years.

As global demand for stainless steel continues to rise, particularly in sectors like construction and transportation, the industry's efforts to reduce its CO2 footprint are more important than ever. The long-term sustainability of stainless steel hinges on its ability to balance production efficiency with environmental responsibility.

Conclusion

The stainless steel industry plays a vital role in modern infrastructure but must tackle its CO2 emissions to ensure long-term sustainability. Although scrap-based production provides a more eco-friendly alternative, the global shortage of scrap materials means that NPI-based production will remain necessary for the foreseeable future. However, with continuous efforts to boost recycling and enhance energy efficiency, the industry is moving toward reducing its carbon footprint and contributing to a more sustainable future.