Product Service Systems (PSS), a generic term for business models that encourage consumers to shift their consumption activities from ownership to use, such as renting and sharing, have long attracted attention for their potential to meet customer needs while reducing adverse environmental impact through dematerialization. Many LCA case studies have been published in the past fifteen years to quantify the environmental performance of PSS, but in reality, assessing a PSS, which has both product and service attributes, using LCA is complicated and not a simple task. In this paper, we first explain the environmental impact assessment method of PSS using LCA based on the existing literature to clarify the challenges to be addressed when conducting LCA of PSS. Then, we take a clothing rental service as an example to discuss how the setting of the objective and scope of the study affects the conclusions and interpretation based on cases. We lastly summarize recommendations for practitioners who will conduct LCA of PSS in the future.

This paper examines consumer acceptance of used products through reuse and sharing, focusing on their effectiveness for Circular Economy-driven product utilization. Regarding current consumer usage, reuse shows high applicability for irregularly used hobby items, while sharing is highly suitable for event clothing with extremely low usage frequency throughout one’s life stage. This indicates the necessity of proposing forms of utilization tailored to existing consumer lifestyles and needs. Two key insights emerged for promoting consumer acceptance of these models utilizing used products. First, overcoming ingrained existing habits is a major challenge for consumer behavioral change. For those without prior experience, habit modification itself remains a significant barrier. Second, for experienced consumers, it is crucial to demonstrate contributions to efficiency and convenience, especially regarding cost and effort savings, for their continued acceptance. These findings offer practical insights for establishing sustainable business models that reduce environmental impact and contribute to societal integration.

This paper discusses system design methods for sharing businesses towards a circular economy (CE). While sharing can contribute to reducing environmental burdens by intensifying product utilization, rebound or backfire effects may increase such environmental burdens. The paper introduces the concept of a circular ecosystem and emphasizes the importance of proactive evaluation and design considering consumer behaviors. Furthermore, we present two case studies – one on durable goods sharing businesses using multi-agent simulation, and another on a bike-sharing business applying scenario design, highlighting the effectiveness of policy interventions and business strategies and the need for segment-specific strategies. Finally, we identify future research challenges that need to be addressed to advance the social implementation of system design for sharing businesses.

New business models such as sharing and subscriptions are highly anticipated as efforts toward carbon neutrality, but there has been much debate regarding their actual effectiveness. This article introduced several sharing case studies examined by author’s research group—namely, umbrellas, baby products, and electric scooters—highlighting the considerations and discussions that arose during the evaluation of these examples. In LCA, the functional unit is one of the key concepts, but in the evaluation of sharing models, it is often the case that setting such a functional unit is not suitable, and sufficient discussion has yet to take place on what frameworks for comparison exist in such cases. It is probably necessary to evaluate changes in the entire system, including rebound effects, but it is also true that such assessments are not simple. With that in mind, we hope that, based on various case studies, discussions will progress toward more appropriate evaluation methods. Keywords: sharing, subscription, functional unit, rebound effect, system change

Recently, supply chains have become more complex and diverse due to globalization, making it more difficult to identify the sources of environmental impact. It has become necessary to consider the responsibility for indirect emissions from Scope 3.　 This paper focused on the Japanese construction industry, which had a high ratio of indirect emissions and has been affected by the rising cost of materials and attempt to clarify the entire picture of the long and complex supply chain of the Japanese construction industry by the I-O analysis. For this purpose, it developed two methods: one is to analyze supply chains at higher stages in a short time, which was difficult with existing methods, and the other is to eliminate routes that deviate from the reality of the supply chain and derive only valid routes. By analyzing the supply chain by path using these methods, it found that the Japanese pig iron industry plays a central role downstream in the supply chain of the Japanese non-timber non-housing construction industry, and that there are many overseas oil and iron ore mining industries further downstream. It was possible to suggest the possibility of reducing CO2 emissions by changing the source of raw material imports.

The rapid industrialization and urbanization of recent decades have posed severe challenges to the natural environment, resulting in a significant increase in waste production. Ready-mixed concrete (RMC) manufacturers face the dual challenges of managing returned concrete and the disposal of waste generated during the washing process. The volume of returned fresh concrete presents environmental and economic challenges, requiring sustainable solutions for resource recovery and waste minimization. Given the need for sustainable development, an increasing number of recycled waste materials and industrial by-products are being utilized to develop sustainable, eco-friendly, controlled low-strength materials (CLSM). Nonetheless, the environmental benefits and impact of this type of material are still insufficiently quantified. This research study employed a Life Cycle Assessment (LCA) to compare the environmental impacts of conventional and eco-friendly CLSM alternatives. A comparative LCA was performed using the ReCiPe 2016 Midpoint (H) life cycle impact assessment method in the OpenLCA software. The results indicated that eco-friendly CLSM, which incorporates returned concrete waste and industrial by-products, is the more sustainable option across all six impact categories when compared to conventional CLSM. Therefore, this study will be helpful for RMC and contractors in facilitating their decision-making process for selecting a more sustainable CLSM.