We present a comprehensive analysis of steel use in the future compiled using dynamic material flow analysis (MFA). A dynamic MFA for 42 countries depicted the global in-use stock and flow up to the end of 2005. On the basis of the transition of steel stock for 2005, the growth of future steel stock was then estimated considering the economic growth for every country. Future steel demand was estimated using dynamic analysis under the new concept of "stocks drive flows". The significant results follow. World steel stock reached 12.7 billion t in 2005, and has doubled in the last 25 years. The world stock in 2005 mainly consisted of construction (60%) and vehicles (10%). Stock in these end uses will reach 55 billion t in 2050, driven by a 10-fold increase in Asia. Steel demand will reach 1.8 billion t in 2025, then slightly decrease, and rise again by replacement of buildings. The forecast of demand clearly represents the industrial shift; at first the increase is dominated by construction, and then, after 2025, demand for construction decreases and demand for vehicles increases instead. This study thus provides the dynamic mechanism of steel stock and flow toward the future, which contributes to the design of sustainable steel use.
In 2010, Chinese export restrictions caused the price of the rare earth element neodymium to increase by a factor of 10, only to return to almost normal levels in the following months. This despite the fact that the restrictions were not lifted. The significant price peak shows that this material supply chain was only weakly resistant to a major supply disruption. However, the fact that prices rapidly returned to lower levels implies a certain resilience. With the help of a novel approach, based on resilience theory combined with a material flow analysis (MFA) based representation of the neodymium magnet (NdFeB) supply chain, we show that supply chain resilience is composed of various mechanisms, including (a) resistance, (b) rapidity, and (c) flexibility, that originate from different parts of the supply chain. We make recommendations to improve the capacity of the NdFeB system to deal with future disruptions and discuss potential generalities for the resilience of other material supply chains.
We introduce several new resilience metrics for quantifying
the resilience of critical material supply chains to disruptions and
validate these metrics using the 2010 rare earth element (REE) crisis
as a case study. Our method is a novel application of Event Sequence
Analysis, supplemented with interviews of actors across the entire
supply chain. We discuss resilience mechanisms in quantitative terms–time
lags, response speeds, and maximum magnitudes–and in light
of cultural differences between Japanese and European corporate practice.
This quantification is crucial if resilience is ever to be taken into
account in criticality assessments and a step toward determining supply
and demand elasticities in the REE supply chain. We find that the
REE system showed resilience mainly through substitution and increased
non-Chinese primary production, with a distinct role for stockpiling.
Overall, annual substitution rates reached 10% of total demand. Non-Chinese
primary production ramped up at a speed of 4% of total market volume
per year. The compound effect of these mechanisms was that recovery
from the 2010 disruption took two years. The supply disruption did
not nudge a system toward an appreciable degree of recycling. This
finding has important implications for the circular economy concept,
indicating that quite a long period of sustained material constraints
will be necessary for a production-consumption system to naturally
evolve toward a circular configuration.
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