Construction is a notoriously carbon-intensive industry. Amongst the many materials used in construction, steel is one of the most common, but its production is traditionally one of the most polluting. This article will explore the sustainability of steel in the construction industry.
Image Credit: M2020/Shutterstock.com
Steel: A Heavily Carbon-intensive Construction Material
Steel is a ubiquitous material found in nearly everything from domestic goods, automobiles, and aeroplanes to towering skyscrapers and megaprojects. It could be said that steel is literally one of the materials that has built the modern epoch.
However, this widespread use comes with a critical downside: sustainability and carbon emissions. Currently, around 75% of all steel produced globally is made in emissions-heavy coal-fired blast furnaces, which require vast amounts of energy to reach the desired heat.
This carbon-heavy manufacturing process means that steel is one of the most environmentally polluting materials used today, with its production responsible for around 8% of global carbon dioxide emissions. This is around the same percentage as concrete, the other main construction material used globally.
Taken together, steel and concrete production are responsible for over a tenth of all global carbon dioxide emissions. This growth has mainly been due to rapidly accelerating urbanization and development which, whilst it has its benefits for the world population’s standard of living, is helping to drive climate change.
This means that the construction industry is a key industrial sector that needs to be rapidly decarbonized to meet net zero and UN sustainable development goals. The IEA estimates that carbon emissions from steel production alone must be reduced by 50% by 2050 and then continue to be reduced to meet the industry’s targets.
Green Steel: Routes to Sustainability in the Steel and Construction Industry
Some experts believe that the way forward is in so-called “green steel.” Essentially, green steel does not use any fossil fuels at all in its manufacture, instead using sustainable, renewable, green sources of energy.
Green hydrogen has been explored as one potential energy source for future sustainable steel production, which could significantly reduce the steel industry’s carbon footprint. Hydrogen only produces water and energy when burned, making it a far cleaner energy carrier than conventional hydrocarbons in use today.
However, most hydrogen in use today is so-called “grey” hydrogen, which is produced by burning natural gas. This is a cheap and abundant option, but still emits CO2. To truly realize sustainability goals, hydrogen must be produced from sustainable processes such as electrolysis.
Another route to sustainability and green steel is the use of electric arc furnaces. As the name suggests, these furnaces use electricity rather than fossil fuels to heat raw materials and produce steel and are gradually replacing conventional coal-fired furnaces.
Current challenges with decarbonizing the steelmaking industry, which will benefit the construction industry, involve scale, cost, and the amount of renewables in the overall energy mix.
A bottleneck for green steel is the massive amounts of investment needed. It is estimated that many billions of dollars will be needed for green steel production at scale. ArcelorMittal, Europe’s biggest steel maker, estimates that up to $40 billion will be needed to decarbonize its operations in line with EU targets alone.
Case Study: SSAB Zero and SSAB Fossil-Free
SSAB ZeroTM is one potential solution to the steelmaking industry and construction’s challenges when it comes to green steel. In this process, recycled steel in the form of scrap metal is inserted into an electric furnace, utilizing biogas and renewable electricity to power the process.
However, scrap steel will not be enough to meet global construction demand. SSAB Fossil-FreeTM uses raw iron ore, like conventional steelmaking, but without the use of fossil fuels. Used together, these green steel options could help to satisfy the demands and decarbonization goals of the global construction industry.
Key Hurdles in the Construction Industry
Beyond technical challenges, the construction industry faces significant structural and economic hurdles for using sustainable steel. The low margins within the construction sector make companies reticent to adopt green technologies, for a start.
Another barrier has to do with how companies count individual emissions from steel consumed during construction. Several factors are at play here, such as a lack of coherent regulations and industry standards and a lack of tools that measure embodied carbon. The value chain is largely fragmented.
Some Sustainable Steel Construction Projects
Whilst the share of sustainable steel in the construction industry is nowhere near its carbon-intensive counterpart, a number of innovative projects have made use of it.
In Chile, architects have designed a modular building prototype partly constructed from recycled steel to address the housing crisis. Recycled wood fiber panels and sub-modules are installed in recycled steel frames. These are lightweight and, according to the designers, have anti-seismic capabilities.
Over in the US city of Detroit, Undecorated, a Detroit-based studio, has designed apartments within an elongated Quonset hut, a prefabricated design popular during World War II in the USA. Termed “The Caterpillar,” the structure’s enclosure is partly constructed from recycled steel.
In Karnataka, India, recycled steel supports are a core element of a new lakeside restaurant at the Deva Dhare Resort. Designed by Play Architecture, a Bangalore-based studio, the building was shortlisted in the Deezen Awards 2022.
In Conclusion
Whilst the construction industry is traditionally slow to embrace new technologies due to concerns including cost, the need to rapidly decarbonize the sector to meet net zero emissions goals has focused attention on sustainable alternatives to processes, materials, and technologies.
Steel is one of the most commonly used materials within the construction industry, but it is also one of the most carbon-intensive. Decarbonizing steel construction through the use of renewable energy, recycled steel, and new technologies will help to significantly reduce the emissions from this key economic sector.
More from AZoBuild: An Overview of Thermal Energy Storage in Concrete
References and Further Reading
Ellerbeck, S (2022) What is green steel and why does the world need more of it? [online] weforum.org. Available at:
https://www.weforum.org/agenda/2022/07/green-steel-emissions-net-zero/
McKinsey (2022) Net-zero steel in building and construction: The way forward [online] mckinsey.com. Available at:
https://www.mckinsey.com/capabilities/sustainability/our-insights/net-zero-steel-in-building-and-construction-the-way-forward
Mazade, K (2023) Ignacio Rojas Hirigoyen develops modular building system to address housing crisis [online] dezeen.com. Available at:
https://www.dezeen.com/2023/03/14/ignacio-rojas-hirigoyen-modular-building-global-housing-crisis/
McKnight, J (2023) Undecorated creates The Caterpillar apartment building in Detroit [online] dezeen.com. Available at:
https://www.dezeen.com/2023/01/12/undecorated-caterpillar-apartment-detroit/
Astbury, J (2022) Play Architecture tops restaurant in India with undulating tiled roof [online] dezeen.com. Available at:
https://www.dezeen.com/2022/09/20/play-architecture-deva-dhare-resort-restaurant-india
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.