We are very happy to announce that Lasting project PhD candidate Kamila Krych will defend her thesis “Lifetimes of consumer products: modeling, trends, and policy for lifetime extension” on Monday the 27th of January 2025. She has been enrolled in the Industrial Ecology Programme at Faculty of Engineering at Norwegian University of Science and Technology (NTNU). Her PhD work has been supervised by Johan Berg Pettersen, Daniel Beat Müller and Kirsi Laitala.
Program
10:15 – 11:00 Trial lecture “Lengthening of lifespan compared to other circular economy strategies”
13:15 – 16:00 Presentation and the public defense of the thesis
Location
The dissertation room in the Main Building at Gløshaugen, Trondheim.
The defense will also be streamed (please contact Kirsi Laitala for the link).
Assessment Committee
- Ester van der Voet, Professor emeritus at the Department Industrial Ecology of the Institute of Environmental Sciences, Leiden University
- Carl Dalhammar, Associate professor at the International Institute for Industrial Environmental Economics, Lund University
- Juudit Ottelin, Associate Professor at the Department of Energy and Process Engineering, NTNU
Abstract
Global resource use and waste generation have been increasing exponentially, motivating efforts toward resource efficiency and circular economy. One promising solution is product lifetime extension, which can potentially reduce the demand for new products and the associated resource use, greenhouse gas emissions, and other impacts. However, longer product lifetimes may involve environmental trade-offs and behavioral rebound effects, calling for a systemic perspective considering the product’s life cycle and the consumer.
This thesis investigates the environmental benefits of product lifetime extension by combining industrial ecology methods, i.e., material flow analysis (MFA) and life cycle assessment (LCA), with insights from social approaches to consumption, particularly social practice theories. The thesis contribution includes: 1) creation of a framework for comprehensive modeling of lifetimes in dynamic MFA, 2) development of a model investigating the historical trends in the lifetimes of large domestic appliances in Norway, and 3) environmental impact assessment of product lifetime extension strategies in Norway, exploring the potential of policy for large household appliances and of alternative consumption modes for clothing.
The created modeling framework distinguishes two main types of influences on product lifetime: product “nature” (inherent product durability) and “nurture” (external influences, e.g., repair). The framework is useful for studying the effect of changes in product lifetimes on stocks, and flows, which is essential for analyzing policy-relevant circular economy strategies. The investigation of historical lifetimes showed no uniform trend across large domestic appliances, with only washing machines and ovens clearly experiencing a lifetime decrease of around 40% observed in the 1990s-2000s. While the reasons for this decrease are unknown, the consumer practice perspective suggests hypotheses involving changes in laundry practices and in how kitchens are designed and renovated. Finally, the thesis shows that product lifetime extension offers significant potential for environmental savings, particularly if changes in product design (“nature”) and consumer practices (“nurture”) are encouraged by policy, e.g., ecodesign, right-to-repair, and more holistic approaches.
Overall, understanding consumer practices and the broader context of consumption was shown to be essential for devising successful lifetime extension policies. A deeper engagement of modelers and policymakers in the consumption context could be helpful in addressing systemic issues and thus accelerate efforts toward resource efficiency and circular economy.