How does the circular economy help today's emissions?

How does the circular economy help today's emissions?

There are many different facets to the circular economy including material efficiency, reuse and recycling. Steel has excellent circular economy credentials both as a material which is strong, durable, versatile and recyclable and, as a structural framing system, which is lightweight, flexible, adaptable and reusable.

While the focus of the circular economy in construction is on how to transition from a linear to a circular model, because of steel’s excellent recycling credentials steel is already circular with very little ‘leakage’ out of the system. Recovery rates for structural steel, for reuse and recycling, are over 95%. Globally, these high recovery and recycling rates translate into savings of around 950 mtCO2 per year.

A circular economy is based on the principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems. Figure 6, developed by the Ellen McArthur foundation, is one of the best accepted representations of circular economy concepts. The left hand (green) half of the figure represents biological cycles such as timber and the right-hand side (blue) represents technical materials, including, in the context of construction, concrete, metals, plastics, etc.

There are two fundamental concepts to highlight within the figure:

  1. Leakage out of the circular system, to energy recovery or landfill, should be avoided wherever possible.
  2. Within the concentric circles, the smaller the diameter the more efficient the process.

Steel has excellent circular economy credentials both as a material which is strong, durable, versatile and recyclable and, as a structural framing system, which is lightweight, flexible, adaptable and reusable.

While the focus of the circular economy in construction is on how to transition from a linear to a circular model, because of steel’s excellent recycling credentials [8] steel is already circular with very little ‘leakage’ out of the system. Recovery rates for structural steel, for reuse and recycling, are over 95% and, with steel recycling emitting only 20% of the carbon emissions compared to making steel from iron ore, steel is already helping significantly to reduce carbon emissions.

But the steel sector is not content with just recycling and is looking to improve its circular credentials further by encouraging greater steel reuse and designing to facilitate future deconstruction and reuse. Steel structures and structural steel elements are inherently demountable and reusable. While there are currently logistical and supply chain barriers to more mainstream reuse, reuse is technically viable, saves resources and carbon emissions and can save money.

To help facilitate structural steel reuse, SCI has recently published guidance documents:

  • SCI P427 Structural steel reuse: a protocol for reusing existing structural steel,
  • SCI P428 Guidance on demountable composite construction systems for UK practice.