The steel industry, circularity and the stock-flow-service nexus

Steel is the world’s most recycled metal, yet only 21% of the global demand is met through scrap, which highlights the gap between the present reality and the ideals embedded in the concept of the circular economy.

The latter is designed to increase material recoverability and product optimisation throughout the entire life cycle, resulting in less carbon emissions, waste and resource dependency.

Within the steel industry, leading companies and professional bodies have sought to promote and embody the circular economy to advance sector sustainability.This project will use the Stock-Flow-Service (SFS) Nexus to quantify the circularity of an international steel company’s products from extraction to service.

The SFS nexus is a conceptual framework that explicitly highlights the interactions, including trade-offs, between energy and material flows (e.g. coal, iron ore), material stocks (e.g. buildings, vehicles) and service provision (e.g. shelter, mobility).

By applying this nexus, one can assess the overall environmental performance of a light weighting strategy by juxtaposing reduced fuel consumption and carbon emissions with the increased incorporation of complex material composites.

The latter make energy savings possible but are difficult to re-use and recycle, thus reducing the circularity of the process.The project will use Material Flow Analysis and Dynamic Stock Modelling to quantify resource consumption and accumulation linked to the service provided by steel.

A set of resource efficiency and circularity indicators will be developed to evaluate the environmental performance of steel products (and prototypes) under various business strategies, including stock optimisation, green leasing, and product-service systems.

The project’s results and recommendations will support the steel company in their corporate sustainability targets and facilitate the accurate prediction and tracking of steel’s residual value and resource efficiency across their product range.