André Cabrera Serrenho

How Will Copper Contamination Constrain Future Global Steel Recycling

Copper in steel causes metallurgical problems, but is pervasive in end-of-life scrap and cannot currently be removed commercially once in the melt. Contamination can be managed to an extent by globally trading scrap for use in tolerant applications and dilution with primary iron sources. However, the viability of long-term strategies can only be evaluated with a complete characterization of copper in the global steel system and this is presented in this paper. The copper concentration of flows along the 2008 steel supply chain is estimated from a survey of literature data and compared with estimates of the maximum concentration that can be tolerated in steel products. Estimates of final steel demand and scrap supply by sector are taken from a global stock-saturation model to determine when the amount of copper in the steel cycle will exceed that which can be tolerated. Best estimates show that quantities of copper arising from conventional scrap preparation can be managed in the global steel system until 2050 assuming perfectly coordinated trade and extensive dilution, but this strategy will become increasingly impractical. Technical and policy interventions along the supply chain are presented to close product loops before this global constraint.

Industry 1.61803: the transition to an industry with reduced material demand fit for a low carbon future

Arising from a discussion meeting in September 2016, this editorial introduces a special issue on the transition to a future industrial system with greatly reduced demand for material production and attempts to synthesize the main findings. The motivation for such a transition is to reduce industrial greenhouse gas emissions, but unlike previous industrial transformations, there are no major stakeholders who will pursue the change for their own immediate benefit. The special issue, therefore, explores the means by which such a transition could be brought about. The editorial presents an overview of the opportunities identified in the papers of the volume, presents examples of actions that can be taken today to begin the process of change and concludes with an agenda for research that might support a rapid acceleration in the rate of change. This article is part of the themed issue ‘Material demand reduction’.

Useful Work Transitions in Portugal, 1856–2009

The use of heat, as a consequence of industrialization, is a recent evolution to the service economy. In contrast to the conventional approach, we perform a useful work accounting, focusing our analysis on the final uses of energy instead of their sources. This enables the assessment of energy-driven activities and capturing of the structure of energy mixes. In addition, we include important energy flows, such as food for humans and feed for working animals, which are usually absent from energy statistics. We consider five different categories of energy uses: heat, mechanical drive, light, other electric uses, and muscle work. We apply this methodology to account for useful work in Portugal from 1856 to 2009. Different transitions in final energy use are identified in this long-term analysis such as the shifts from firewood to coal and from coal to oil and electricity. Useful work shifts from muscle work to mechanical drive uses, and from low to high temperature.