Addressing food waste prevention is one target of the Sustainable Development Goals (SDGs) and a major task for the UN Environmental Programme and the European Commission. It is promising in terms of its environmental saving potential. However, it also leads to consumers being able to save money, which they then are likely to spend, thus again causing a negative environmental impact. This dimension of the so-called indirect rebound effect, which prevents the desired ecological benefits from being achieved, is investigated in this paper. By using a single-region environmentally extended input-output model from a production perspective, the indirect rebound effects from food waste prevention in Germany are analysed. Any political action needs to consider not only a differentiation in income class, but also alternative concepts such as the principles of sufficiency in order to achieve all ecological benefits and specifically the third target of SDG 12.
The steel industry is responsible for a quarter of all industrial greenhouse gas emissions. So far, the environmental savings are mainly due to steel recycling. Besides recycling, the circular economy offers strategies to increase material efficiency and thus decrease the primary raw material demand. However, the potentials remain unexploited because circular economy concepts with a higher degree of circularity are not considered. The presented case study of an industrial machining knife illustrates how the production process can be improved by implementing various circular strategies. The environmental performance is analyzed by calculating and comparing the carbon footprint, the cumulative energy demand and the material footprint, and the material efficiency indicator. The results show that the implementation of the three overarching strategies of the circular economy - narrowing, closing, and slowing - contributes to a significant increase in material efficiency. The implementation also has a positive effect on the overall environmental performance. The circular production processes require less energy and resources and cause fewer emissions. Auxiliary processes such as additional transport routes are relevant, as they can reduce or even overcompensate for savings. These processes must be adequately considered and designed.
In material development processes, the question if a new alloy is more sustainable than the existing one becomes increasingly significant. Existing studies on metals and alloys show that their composition can make a difference regarding the environmental impact. In this case study, a recently developed air hardening forging steel is used to produce a U-bolt as an example component in automotive engineering. The production process is analyzed regarding the environmental performance and compared with the standard quench and tempering steels 42CrMo4 and 33MnCrB5-2. The analysis is based on results from applying the method of Life Cycle Assessment. First, the production process and the alterations on material, product, and process level are defined. The resulting process flows were quantified and attributed with the environmental impacts covering Carbon Footprint, Cumulative Energy Demand, and Material Footprint as they represent best the resource-, energy- and thus carbon-intensive steel industry. The results show that the development of the air hardening forging steel leads to a higher environmental impact compared to the reference alloys when the material level is considered. Otherwise, the new steel allows changes in manufacturing process, which is why an additional assessment on process level was conducted. It is seen that the air hardening forging steel has environmental savings as it enables skipping a heat treatment process. Superior material characteristics enable the application of lightweight design principles, which further increases the potential environmental savings. The present work shows that the question of the environmental impact does not end with analyzing the raw material only. Rather, the entire manufacturing process of a product must be considered. The case study also shows methodological questions regarding the specification of steel for alloying elements, processes in the metalworking industry and the data availability and quality in Life Cycle Assessment.
Das zentrale Anliegen des Projektes besteht darin, regionale Stoffkreisläufe in der metallverarbeitenden Industrie zu schließen - mit einem Schwerpunkt auf (Hand-) Werkzeuge und Schneidwaren - sowie dies durch den Einsatz digitaler Technologien zu organisieren und zu optimieren. Das Ziel ist, Ressourcen- und Energieverbräuche zu reduzieren sowie ökonomische Vorteile für die Unternehmen zu realisieren. Im Detail soll es darum gehen, verschlissene metallische Produkte am End-of-Life nicht einer Verwertung durch Umschmelzen zuzuführen, sondern durch Remanufacturing und Repurposing die Nutzungsdauer der mit hohem Energie- und Ressourcenaufwand erzeugten Metalle zu verlängern. Diese Ansätze sollen unternehmensübergreifend aufgestellt werden und erfordern eine digital unterstützte Logistikkette sowie eine vollständige Rückverfolgbarkeit. Eine Rückführung verschlissener Maschinenmesser lohnt sich nach derzeitigem Kenntnisstand nicht, wenn dieses Material nur den Schrottpreis aufweist. Im Projekt "Circle of Tools" soll daher ein neues Geschäftsmodell entwickelt werden, das darauf basiert, sortenreine, qualitativ hochwertige Materialien entweder im primären Herstellungsprozess zu nutzen oder zur Weiterverarbeitung in andere Herstellungsprozesse unternehmensübergreifend zu integrieren. Neben den rein technischen Möglichkeiten werden betriebswirtschaftliche Faktoren, das Ressourceneffizienzpotenzial und der rechtliche Rahmen untersucht.
Die in der europäischen Abfallrahmenrichtlinie und dem deutschen Kreislaufwirtschaftsgesetz verankerte Abfallhierarchie geht von der grundsätzlichen ökologischen Vorteilhaftigkeit der unterschiedlichen Stufen aus. Während das stoffliche Recycling von Produkten in der Regel vorteilhafter ist als ihre thermische Verwertung oder Deponierung, sind Reuse/Kaskadennutzung demnach ökologisch vorteilhafter als sämtliche Recyclingtechnologien. Die Datenlage ist hier jedoch im Vergleich zu vielen Recyclingtechnologien noch äußerst lückenhaft und unsystematisch. Einzelne Untersuchungen weisen jedoch auf signifikante Ressourceneffizienzpotenziale hin. Abschätzungen zeigen, dass die in diesem Vorhaben angedachte Reuse-/Kaskadennutzung zu einer Einsparung von 300 Tonnen Primär-Werkzeugstahl führen könnte. Das Vorhaben kann diese signifikanten Potenziale nachweisen und gleichzeitig geeignete und übertragbare Geschäftsmodelle aufzeigen. Auf Grundlage der empirischen Erhebungen werden im Projekt genaue Wirkungen berechnet für folgende Fragen: (1) Welche Mengen an Rohstoffe können durch Remanufacturing/Repurposing eingespart werden? (2) Welche ökonomische Wertschöpfung ist damit zu erzielen? (3) Wie ist ein Remanufacturing/Repurposing im Vergleich zu anderen Verwertungsverfahren ökologisch und ökonomisch einzuschätzen?
The implementation of the circular economy is crucial to combat climate change especially in energy- and carbon-intensive sectors like the steel industry. It requires the environmental assessment of circular interventions to steel products to ensure that they are in line with targets of the circular economy - increase of resource efficiency and sustainability. Based on previous case studies and established methodologies, an environmental assessment framework is suggested and applied. It comprises a Material Flow Analysis to quantify selected mass-based indicators to evaluate the parameters of circular economy, as well as a Life Cycle Assessment to quantify the difference of the environmental impact. The application to a case study in the metalworking industries shows that the implementation of repurposing to a machining knife and hand tools contributes to all circular economy strategies - narrowing, slowing, and closing. At first, however, the circular intervention did not lead to a reduction of the environmental impact. It was found that the optimization of share of secondary material, energy mix, grinding, and transportation can lower the environmental impact of the circular compared to the conventional product system. Considering the increased product functionality, the environmental performance of the circular product system is superior. The study shows the importance of integrating assessment methods covering the resource level and environmental sustainability since focusing only on the resource efficiency can be misleading. At the same time, it stresses the need to apply environmental assessments in the product development stage to design environmentally sustainable and resource-efficient product systems.
