We present a dynamic model of global copper stocks and flows which allows a detailed analysis of recycling efficiencies, copper stocks in use, and dissipated and landfilled copper. The model is based on historical mining and refined copper production data (1910–2010) enhanced by a unique data set of recent global semifinished goods production and copper end-use sectors provided by the copper industry. To enable the consistency of the simulated copper life cycle in terms of a closed mass balance, particularly the matching of recycled metal flows to reported historical annual production data, a method was developed to estimate the yearly global collection rates of end-of-life (postconsumer) scrap. Based on this method, we provide estimates of 8 different recycling indicators over time. The main indicator for the efficiency of global copper recycling from end-of-life (EoL) scrap—the EoL recycling rate—was estimated to be 45% on average, ± 5% (one standard deviation) due to uncertainty and variability over time in the period 2000–2010. As uncertainties of specific input data—mainly concerning assumptions on end-use lifetimes and their distribution—are high, a sensitivity analysis with regard to the effect of uncertainties in the input data on the calculated recycling indicators was performed. The sensitivity analysis included a stochastic (Monte Carlo) uncertainty evaluation with 10⁵ simulation runs.

Reaching the sustainable development goals needs innovations. This paper addresses the dynamics of green energy and resource efficiency innovations, and looks at the positioning of countries from the North and emerging economies. We use indicators for both general innovation capabilities and specific green technology capabilities. Data on general innovation capabilities reveal that the traditional OECD countries, by and large, still possess advantages compared to Newly Industrializing Countries (NICs). Literature and Patent indicators reveal that the innovation dynamics are particularly high for publications. Literature and exports indicators reveal that the South has been catching up substantially. With regard to patents, some countries of the South are catching up, but the North is still cleary leading. A detailed analysis of co-patenting and country-to-country trade data reveals a more differentiated picture: Leading countries from Europe such as Germany as still specializing on serving the markets of traditional OECD countries. Japan and Korea are very reluctant with regard to co-patenting, but specialize in exporting to China. South-South trade in green technologies is the fastest growing market segment. However, countries of the South are pursuing a differentiated strategy: Mexico is highly integrated into the US economy. Singapore and South Korea have been catching up and provide technologies especially for China. China itself is following a double strategy, with absorbing technology from the North in order to compete on markets of the North on the one hand, but increasingly specializing on becoming lead supplier for countries of the South on the other hand. The other technology providers from the South are mainly specializing in supplying other countries from the South. Thus, a segmentation of the market is likely, with green sustainability innovations in the South more likely originating in the South as well, and China being an important country to adapt knowledge from the North to the needs of the South.

Climate change is a major concern for the sustainable development of global energy systems. Hydrogen produced through water electrolysis offers a crucial solution by storing and generating renewable energy with minimal environmental impact, thereby reducing carbon emissions in the energy sector. Our research evaluates current hydrogen production technologies, such as alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), solid oxide electrolysis (SOEC), and anion exchange membrane water electrolysis (AEMWE). We systematically review life cycle assessments (LCA) for these technologies, analyzing their environmental impacts and recent technological advancements. This study fills essential gaps by providing detailed LCAs for emerging technologies and evaluating their scalability and environmental footprints. Our analysis outlines the strengths and weaknesses of each technology, guiding future research and assisting stakeholders in making informed decisions about integrating hydrogen production into the global energy mix. Our approach highlights operational efficiencies and potential sustainability enhancements by employing comparative analyses and reviewing advancements in membrane technology and electrocatalysts. A significant finding is that PEMWE when integrated with renewable energy sources, offers rapid response capabilities that are vital for adaptive energy systems and reducing carbon footprints.

In the coming decades, the number of end-of-life (EoL) traction battery systems will increase sharply. The disassembly of the system to the battery module is necessary to recycle the battery modules or to be able to use them for further second-life applications. These different recovery paths are important pathways to archive a circular battery supply chain. So far, little knowledge about the disassembling of EoL batteries exists. Based on a disassembly experiment of a plug-in hybrid battery system, we present results regarding the battery set-up, including their fasteners, the necessary disassembly steps, and the sequence. Upon the experimental data, we assess the disassembly duration of the battery system under uncertainty with a fuzzy logic approach. The results indicate that a disassembling time of about 22 min is expected for the battery system in the field study if one worker conducts the process. An estimation for disassembling costs per battery system is performed for a plant in Germany. Depending on the plant capacity, the disassembling to battery module level is associated with costs between EUR 80 and 100 per battery system.