A stock-driven model for assessing environmental benefits of product lifetime extension in Norwegian households

Household consumption of durable goods is associated with environmental impacts in production, use and end-of-life treatment, all of which could be affected by actions to extend product lifetime. In order to estimate environmental benefits and direct strategies for lifetime extension we need to understand the consumption dynamics for durable goods. In this paper we present a stock-driven dynamic model of household durables based on material flow analysis (MFA) methodology. We investigate the stocks and flows of furniture and appliances in Norwegian households, using population and product ownership rate as drivers for stock levels and socioeconomic drivers project future stock requirements. The model is calibrated by collecting historical data on ownership, purchase, and disposal of such goods. The considered durables are divided into representative archetypes characterized by typical service lifetime. The dynamic, vintage modelling approach is well suited to consider effects such as an increased need for maintenance and/or operational energy among household products with prolonged lifetime. We illustrate uses for the model to quantify impacts caused by demand for goods and the environmental system effects associated with lifetime extension, and we discuss insights to direct effective measures. Potential applications include a support for product design, household behavior campaigns and environmental policy making.