CO2-reduced steel – Sustainable and climate-friendly

Steel enables the construction of bridges, ships, industrial plants, and skyscrapers and is indispensable in the modern world. However, conventional steel production is among the largest sources of CO2 emissions worldwide. Around seven percent of global CO2 emissions come from the steel industry.

The demand for environmentally friendly alternatives is growing rapidly. CO2-reduced steel offers the same strength, handling, and durability as conventional steel but with a significantly better environmental footprint.

But what does CO2-reduced steel mean? Which technologies make CO2 reduction possible? And when will CO2-free steel become usable for the industry? This article provides all the essential information about sustainable steel.

What is CO2-reduced steel?

CO2-reduced steel is produced using methods that generate low CO2 emissions during the production process. Various technologies are used:

Electric arc furnaces with green electricity
Traditional blast furnaces rely on coal or coke. In contrast, modern EAF systems use renewable electricity to melt recycled steel scrap. This saves up to eighty percent of CO2 compared to conventional steel production.
Direct reduction process with hydrogen
In traditional iron production, iron ore is reduced with carbon, resulting in large amounts of CO2. With the direct reduced iron process, green hydrogen replaces carbon. The result is an almost emission-free steel production.
Blast furnace optimization with hydrogen and biomass
Some manufacturers reduce their carbon content by using hydrogen or biogenic substitutes to lower CO2 emissions.
CO2 capture and storage
Another method is CO2 capture, in which the resulting carbon dioxide is captured and permanently stored instead of being released into the atmosphere.
Increased recycling share
Steel is one hundred percent recyclable without any loss in quality. The increased use of recycled steel not only reduces CO2 emissions but also conserves valuable raw materials.

Thanks to these technologies, it is possible to reduce CO2 emissions by thirty to eighty percent compared to traditional steel.

When will CO2-free steel be available?

CO2-free steel, meaning steel produced entirely without fossil fuels, will not be available in large quantities until around 2045.
Some companies have already put pilot plants for completely CO2-free steel into operation.

Why is it taking so long?

The transition to CO2-free production requires massive investments in new facilities, the provision of green hydrogen, and the establishment of a stable supply chain for renewable energy. Until then, CO2-reduced steel remains the most environmentally friendly option.

What types of CO2-reduced steel are available?

CO2-reduced steel is available in various grades. Especially in bridge and shipbuilding, the following steel types are relevant:

Steel grade	Properties
S355J2+N	Bridge construction, high-load bearing
S355J2+N according to railway standard DBS 918002-02	Bridge construction according to ZTV-ING and specification DBS918005
S235J2+N	Pedestrian and bicycle bridges, construction
S235J2+N according to railway standard DBS 918002-02	Pedestrian and bicycle bridges according to ZTV-ING and specification DBS918005
S355J2W	Weather-resistant steel structures
S355J2WP	Outdoor areas with natural corrosion protection
D36	Shipbuilding, offshore constructions
E36	Heavy-duty areas, shipyards
Grad A	General shipbuilding, maritime applications

These steel grades offer the same mechanical properties as conventional construction steel, but with reduced CO2 emissions.

Technical and chemical composition of CO2-reduced steel

Basically, the chemical composition is the same as conventional construction steel.

C (Carbon): The carbon content in steel affects its strength and toughness. In CO2-reduced steel, the carbon content can vary depending on the manufacturing process and final product. Typical contents range from 0.05% to 0.2%.
Mn (Manganese): Manganese is added to improve the strength and workability of the steel. The typical manganese content is between 0.8% and 1.6%.
Si (Silicon): Silicon is used for desulfurization and to improve corrosion resistance. The content is usually between 0.2% and 0.5%.
P (Phosphorus): Phosphorus is present in small amounts (0.02% to 0.1%) because it can negatively affect the toughness of the steel.
S (Sulfur): The sulfur content is limited to minimal values of 0.02% to 0.05% to maximize weldability.
Cr (Chromium), Ni (Nickel): In special steels, such as stainless steel, chromium and nickel are also present, but in smaller amounts compared to highly alloyed stainless steels.

The combination of these elements gives CO2-reduced steel high strength, formability, and corrosion resistance, while minimizing CO2 emissions during the manufacturing process.

Technical properties

CO2-reduced steel has the same mechanical properties as conventional steel, as the alloy components remain largely the same. The steel has high tensile strength, elongation, and excellent welding properties, which are crucial for applications such as bridge construction, shipbuilding, and other uses.

Advantages of CO2-reduced steel

Sustainability without compromising quality: CO2-reduced steel offers the same strength, corrosion resistance, and durability as traditional steel.
Competitive advantages in tenders: Public construction projects and shipyards are increasingly opting for sustainable materials. Using CO2-reduced steel improves the position in tenders.
Savings on CO2 costs: With rising CO2 taxes and emission certificates, CO2-reduced steel is becoming economically more attractive.
Future-proofing for the industry: The EU and many countries are tightening their climate targets. Those who adopt CO2-reduced steel early secure a stable long-term position in the market.

Applications: Where does CO2-reduced steel make a difference?

Thanks to its excellent properties, CO2-reduced steel is used in many areas.

Bridge construction

Bicycle and pedestrian bridges
Road and highway bridges
Structures for sustainable infrastructure

Industrial construction and infrastructure

High-rise buildings with sustainable steel structures
Industrial halls and heavy-duty constructions
CO2-optimized large-scale projects

Shipbuilding and shipyards

Freight ships and passenger ships
Offshore platforms
Shipyards with CO2-optimized production processes

Introduction of CO2-reduced steel

Higher production costs: The production of CO2-reduced steel is currently more expensive than conventional steel. However, prices are expected to decrease as demand increases.
Availability and scaling: Production capacities are still limited. Companies should plan early to secure CO2-reduced steel for large projects.

Technological developments in CO2-reduced steel production

The steel industry is at a turning point. While the classic blast furnace process still dominates the majority of global steel production, the development of alternative, lower-emission processes is advancing rapidly.

In addition to the already mentioned direct reduction process with hydrogen and the use of electric arc furnaces, there are other technologies that will play a crucial role in the coming years.

Plasma-based reduction

Plasma reduction processes use extremely high temperatures to process iron ore without fossil fuels. Initial trials show that this method could enable almost CO2-free steel production with renewable energy.

Use of synthetic methane

A bridging technology is the use of synthetic methane as a reducing agent. It can be produced from renewable hydrogen and CO2, helping to close the carbon cycle.

Biocoke as a coke substitute

In the future, biocoke from sustainably grown biomass could be used instead of hard coal or coke. This significantly reduces net CO2 emissions, as the carbon released during combustion was previously absorbed from the atmosphere by the plants.

CO2-reduced steel in international comparison

The development of CO2-reduced steel grades is progressing at different speeds worldwide. While Europe is leading with projects like HYBRIT or SALCOS, China, the USA, and Japan are also investing heavily in climate-neutral steel production.

China: Leading in steel production but still heavily dependent on coal. First hydrogen projects are in the pipeline.
USA: Primarily focuses on electric arc furnaces with green electricity. The steel industry here is more focused on recycling.
Japan: Developing new blast furnace technologies with hydrogen-based reduction processes.

Funding programs and political frameworks

Many governments support the transformation of the steel industry through subsidies, funding programs, and regulatory incentives. The key measures include:

EU Green Deal: The European Union is aiming for climate neutrality by 2050 and supports low-carbon steel production through the “Clean Steel Partnership” program.
Carbon Border Adjustment Mechanism (CBAM): This instrument ensures that imported steel also faces CO2 pricing to avoid market distortions.
Funding for Research & Development: Many countries provide financial resources to accelerate innovative steel manufacturing processes.

The future of sustainable steel construction starts now.

CO2-reduced steel offers a real opportunity to make steel construction more sustainable without compromising on quality and performance. While CO2-free steel is still a few decades away from market readiness, CO2-reduced steel can already help reduce emissions and make construction projects future-proof today. Those who make the switch now gain a competitive advantage and actively contribute to the reduction of CO2 emissions.

Calculate the price for CO2-reduced steel

Calculate the price for weather-resistant steel online now.

Your contact person

If you have any questions about our range or services, please feel free to contact our representative. We are happy to assist you.

Heiner Büsselmann

Tel.: +49 (0)421 / 48 40 1922 – 21
E-Mail: hbuesselmann@unionstahl.com

FAQ – Frequently Asked Questions about CO2-reduced Steel

Is CO2-free steel already available for purchase?

No, CO2-free steel is still in the development phase. Widespread market introduction is expected only after 2045. Currently, only CO2-reduced steel is available.

Can CO2-reduced steel be processed in the same way as conventional steel?

Yes, CO2-reduced steel can be welded, cut, and formed using the same techniques as conventional steel.

Where can I source CO2-reduced steel?

You can order CO2-reduced steel from us in many different variations. Contact us now for a personalized offer. We are happy to assist you.