Comparative life cycle assessment of circular and linear product versions for a motorboat and smartphone

The circular economy (CE) is an evolving field and practice that aims for increased resource efficiency of products and services. However, there is still limited literature that demonstrates the environmental impact reduction of circular products or business models. This paper examines and compares two disparate products, a smartphone and a motorised leisure boat. Life cycle assessment (LCA) is used to assess and compare the linear product versions with circular scenarios. For the smartphone (linear version), the production of the integrated circuit (IC) dominates the life cycle impacts with 63 % of the 18.0 kgCO 2 -eq/year climate change impact. For abiotic depletion (ADP) and human toxicity the impacts were dominated by raw material extraction and more evenly spread across the components. The circular scenarios therefore focused on life extension to limit the IC's impact through modularity and cloud offloading, resulting in CO 2 reductions of 35 % and 33 % respectively. However, internal modularity that includes replacing the IC, results in increased impacts. Renewable energy for component production could reduce climate change impact to 4.95 kgCO 2 -eq/year, with modularity reducing it further to 3.3 kgCO 2 -eq (total reduction of 81 %). In contrast, consumption of diesel in the boat's use phase accounts for almost 90 % of the 6700 kgCO 2 -eq/year emissions. However, for ADP and ecotoxicity, electronic components (44 % for both) and maintenance (28 % and 22 %, respectively) dominate the impact. The impact of antifouling paint use is also important for ecotoxicity with 18 % of the impact. Circular scenarios examined for the boat are electrification, prolonged life (from 30 to 50 years) and sharing (five users). Electrification results in a reduction of CO 2 emissions of 80 % but toxicity and ADP increase by 9 % and 17 %, respectively. Shared ownership reduces ADP and ecotoxicity as the manufacturing impacts are shared, but climate change impact is only reduced by 9 % across the lifespan. The results demonstrate that circular responses do not necessarily result in reduced impacts and should be carefully assessed to ensure that reductions in environmental impact occur. Consistent with other studies, the implications of life extension are determined by the impact of energy use, and replacement materials and components. Other responses, that are more aligned with traditional eco-efficiency, can be more effective and should at least be applied initially.