The household sector is a major driver of energy consumption and greenhouse gas (GHG) emissions. However, most existing studies have only estimated households’ carbon footprint from their expenditures. Households’ daily activity time, a scarce resource that limits and determines their consumption behavior, has rarely been integrated into the estimation. Incorporating the daily time-use patterns should thus provide a more practical perspective for mitigation policies aiming at promoting sustainable household lifestyles. In this study, by linking household time-use data and expenditure data of Japan, the carbon footprint and the GHG intensity of time of 85 daily household activities constituting the 24 hours in a day are estimated. Compared to the maximal 20-activity disaggregation in existing studies, our detailed 85-category disaggregation of daily time enables unprecedented details on the discrepancies between the carbon footprint from daily activities, many of which have previous been treated as one activity. Results indicate significant carbon mitigation potential in activities with a high GHG intensity of time, such as cooking, bathing, and mobility-related and activities. Average daily GHG emissions were also found to be higher on weekends as time-use patterns shift from paid work to free-time activities, highlighting the need for mitigation strategies on a weekly scale.
Changes of Japanese consumer preference for electric vehicles (EVs) with new EV commercialisation and subsidy implementation has been quantitatively evaluated by applying conjoint analysis to the respondents choice experiment data collected by internet questionnaire survey that have been conducted in February 2009 and 2010. Powertrains (battery electric vehicle (BEV), gasoline hybrid electric vehicle (HEV) and gasoline plug-in HEV (PHEV)), vehicle price, vehicle range, driving cost and passenger capacity have been chosen as attributes of vehicles and marginal utility and its monetary measure of each attribute have been calculated by setting the gasoline vehicle (GV) with typical specifications as baseline. The estimated results indicate that the vehicle range of BEVs under the current battery technology level lead to utility decline and that those EVs with fewer seats by mounting devices for electric driving would not be accepted by consumers. In terms of powertrain selection, consumers express strong preference for HEVs, whereas for BEVs and PHEVs they express low / negative preference or hold their judgment for choosing. From the comparison of the estimated marginal utilities for powertrain in 2009 and 2010, significant statistical differences are found for HEVs and Kei passenger type BEVs. Moreover, it is confirmed that implementation of has played an important role to enhance consciousness of HEVs and Kei passenger type BEVs as environmentally friendly vehicles. It is true that the current subsidy has played an important role to raise awareness of some kind of EVs. However, in order to improve environment by diffusing other kinds of EVs that have higher environmental performance than HEVs, not only the commercialisation of those kinds of vehicles that satisfy consumer needs at acceptable vehicle price levels but also further schemes should be required to gain consumer recognition especially for BEVs and PHEVs.
A life cycle inventory analysis is conducted in this study to evaluate the environmental merit of a vehicle to home (V2H) system towards the conventional counterpart equivalent in terms of environmental impact category global warming expressed as CO2 emissions. The V2H system comprises a residential house, a photovoltaic solar system, a battery electric vehicle and a charging system, whereas the conventional system includes a residential house, a gasoline vehicle and a petrol station. The system boundary of each components consists of its production, use and end-of-life stages, where data available. CO2 emissions are calculated by applying the data of each components and life cycle stages collected from statistics and literature surveys to the Japanese life cycle inventory database. The emissions differ by the assumptions made; therefore a sensitivity analysis is also carried out to understand the potential variation of the CO2 emissions. The result indicates that about 35-42% CO2 reduction can be expected for a V2H system in comparison with the conventional system. Since the main contributors to CO2 emissions of both systems are dwelling, residential house construction, vehicle cycle and fuel cycle stages, these stages should be included in the system boundary of V2H system and it is important to select and design the appropriate components of these stages to assure the environmental merits of V2H system in terms of life cycle CO2 reduction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.