Conversations about decarbonisation must continue at pace and for these discussions to bring about real change, as an industry we have to push forward in a number of areas, one of those being the acceleration of our transition to a net zero steel future. But what does the built environment need to do – both right now and in the future, to help make lower carbon steel a tangible prospect? Adrian Bywaters, operations director for engineering at Mace, considers the options.
1000 times stronger than iron, steel is one of the most commonly used materials on the planet. There are challenges impacting steel's carbon footprint, but one of the main obstacles is the manufacturing process, which is typically carbon intensive. So decarbonising new steel production will be driven largely by powering furnaces with sustainable energy alternatives. Hydrogen-fuelled furnaces are being billed as a promising option, and there are new steel producers entering the market adopting less carbon intensive manufacturing methods.
Reuse is King
By rethinking our approach to design, material use and collaboration, there are things we can do immediately to reduce carbon in steel. But we must also play the long game – engaging with each other to make better use of resources, while considering the whole lifecycle of a building and its component parts.
When it comes to carbon, reuse of materials will always be preferable to new production. Once steel has been manufactured, it is a permanent resource, so can be infinitely reused and repurposed – without any loss of material properties.
Repurposing steel involves taking existing beams and columns, trimming, cleaning, and treating them, so that they can be used again without adding carbon to the process. But securing supply of the right grade and section size of steel can pose challenges.
Steel can also be melted down if it cannot be reused directly, making recycling a viable option. While melting does require carbon expenditure, it still generates less than manufacturing new steel from raw materials.
Options like electric arc furnaces can incorporate higher scrap content rates and generates a fifth of the carbon compared to the traditional Basic Oxygen Furnace.
We should also be sharing our aspirations with steel suppliers, challenging them to create and find products which meet carbon targets. We can do this by requesting steel and stating the desired level of embodied carbon, instead of defining the manufacturing process or source. This gives suppliers the freedom to source the most carbon efficient way for any given project. As such, this approach does not constrain projects to a manufacturing process or single supplier and engages the steel suppliers' expertise to find the lowest carbon solution available.
Existing Structures and Circularity in Design
Promoting partial or complete repurposing of buildings enables reuse of materials in situ, saving a huge amount of carbon. Wherever possible, we should drive clients to opt for refurbishment, instead of demolishing and building from scratch.
We also owe it to future generations to think about what happens at the end of an asset's life when we are designing new buildings. The buildings we are trying to repurpose now were designed or built 30 to 50 years ago. We should be designing buildings for easier reuse or dismantlement to encourage circularity, creating structures which are easy to repurpose and dismantle. Because if you can dismantle a structure, you can reuse the component parts, reducing the need for raw materials for future projects. Design teams must review architectural intent, structural design, and material availability to assess the options available and constraints of a project - this will enable the lowest carbon solution to be identified.
Acting Now
While the use of sustainable energy to decarbonise the steel supply chain will soon be a workable option, we still need to do everything we can right now to decarbonise steel itself. That means sourcing existing or refurbishing more to utilise steel already available in a structure - instead of building a new one from scratch. When we do have to build new structures, it means designing and building them as sustainably as possible with the lowest embodied carbon.
And the journey doesn't stop there. We need to think about the future use of chosen materials by making those structures easy to demount and repurpose, giving a head start to future generations decarbonisation efforts in the built environment.
For more information visit: www.macegroup.com
IMAGES
01. Image courtesy of Mace
02. By rethinking our approach to design, material use and collaboration, there are things we can do immediately to reduce carbon in steel
