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Residential photovoltaic (PV) battery systems are key technology in the design of low-carbon and resilient energy systems; however, limited research has assessed their profitability. This study aims to evaluate the economic performance of PV battery systems for end-users. The evaluation takes geological, technological, and socio-economic factors into consideration, thereby making the evaluation more comprehensive. We used PV power generation data and power consumption data of more than 40,000 all-electric houses in Japan. We performed scenario analyses with a sensitivity analysis. The results showed that residential PV battery systems were highly profitable when their storage battery operation modes were appropriately utilized at the end of the purchase period for solar power generation in Japan’s feed-in-tariff (FIT) scheme. The profitability, however, varied across regions. The results also indicated that the PV self-consumption rate was more than 50% when charging the battery with surplus power. The results of the sensitivity analysis suggested that the unit prices of grid electricity and the purchasing price of surplus power after the FIT scheme had a significant effect on the profitability of residential PV battery systems.
Tomonori Honda; Akito Ozawa; Hiroko Wakamatsu. Profitability Assessment of Residential Photovoltaic Battery Systems in Japan Using Electric Power Big Data. Sustainability 2021, 13, 5370 .
AMA StyleTomonori Honda, Akito Ozawa, Hiroko Wakamatsu. Profitability Assessment of Residential Photovoltaic Battery Systems in Japan Using Electric Power Big Data. Sustainability. 2021; 13 (10):5370.
Chicago/Turabian StyleTomonori Honda; Akito Ozawa; Hiroko Wakamatsu. 2021. "Profitability Assessment of Residential Photovoltaic Battery Systems in Japan Using Electric Power Big Data." Sustainability 13, no. 10: 5370.
Renewable energy technologies play an important role in the future energy systems, not only to realize a low-carbon society, but also to provide socioeconomic benefits such as creating employment opportunities and revitalizing local economies. This study considers the impact of employment in rural power plants as a socioeconomic benefit and analyzes the transition to a low-carbon energy system using a multi-regional MARKet ALlocation (MARKAL) model. The benefit is monetized in order to incorporate it into a cost minimization objective function, and we focus on the impact of the differences in the value on the Japanese energy system and employment. Our results suggest that when considering employment effects of rural power plants, renewable power generation will increase up to 350 TWh, mainly biomass and solar photovoltaic, in 2030. Total employment associated with power generation facilities in rural areas over the model period (45 y) will increase by up to 2.28 million person-year, and biomass power generation, in particular, can have a significant role in the revitalization of local economies owing to the large job creation effect during its operation and maintenance phase.
Yu Nagatomo; Akito Ozawa; Yuki Kudoh; Hiroki Hondo. Impacts of employment in power generation on renewable-based energy systems in Japan— Analysis using an energy system model. Energy 2021, 226, 120350 .
AMA StyleYu Nagatomo, Akito Ozawa, Yuki Kudoh, Hiroki Hondo. Impacts of employment in power generation on renewable-based energy systems in Japan— Analysis using an energy system model. Energy. 2021; 226 ():120350.
Chicago/Turabian StyleYu Nagatomo; Akito Ozawa; Yuki Kudoh; Hiroki Hondo. 2021. "Impacts of employment in power generation on renewable-based energy systems in Japan— Analysis using an energy system model." Energy 226, no. : 120350.
Shinichirou Morimoto; Kenzo Sanematsu; Kimihiro Ozaki; Akito Ozawa; Yuna Seo. Methodological study of evaluating the traceability of neodymium based on the global substance flow analysis and Monte Carlo simulation. Resources Policy 2019, 63, 1 .
AMA StyleShinichirou Morimoto, Kenzo Sanematsu, Kimihiro Ozaki, Akito Ozawa, Yuna Seo. Methodological study of evaluating the traceability of neodymium based on the global substance flow analysis and Monte Carlo simulation. Resources Policy. 2019; 63 ():1.
Chicago/Turabian StyleShinichirou Morimoto; Kenzo Sanematsu; Kimihiro Ozaki; Akito Ozawa; Yuna Seo. 2019. "Methodological study of evaluating the traceability of neodymium based on the global substance flow analysis and Monte Carlo simulation." Resources Policy 63, no. : 1.
Hydrogen energy carriers such as liquid hydrogen (LH2), methylcyclohexane (MCH), and ammonia (NH3) are promising energy vectors in the clean energy systems currently being developed. However, their effectiveness in mitigating environmental emissions must be assessed by life cycle analyses throughout the supply chain. In this study, while focusing on hydrogen energy carriers, life cycle inventory analyses were conducted to estimate CO2 emissions from the following types of power generation plants in Japan: a hydrogen (H2) mono-firing power plant using LH2 or MCH that originated from overseas renewable electricity; and NH3 co-firing with fossil fuel and NH3 mono-firing power plants using hydrogen energy carriers that originated from overseas natural gas or renewable electricity. Parameters related to the supply chains were collected by literature surveys, and the Japanese life cycle inventory database was primarily used to calculate the emissions. From the results, CO2 hotspots of the target supply chains and potential measures are identified that become necessary to establish low-carbon supply chains.
Akito Ozawa; Yuki Kudoh; Naomi Kitagawa; Ryoji Muramatsu. Life cycle CO2 emissions from power generation using hydrogen energy carriers. International Journal of Hydrogen Energy 2019, 44, 11219 -11232.
AMA StyleAkito Ozawa, Yuki Kudoh, Naomi Kitagawa, Ryoji Muramatsu. Life cycle CO2 emissions from power generation using hydrogen energy carriers. International Journal of Hydrogen Energy. 2019; 44 (21):11219-11232.
Chicago/Turabian StyleAkito Ozawa; Yuki Kudoh; Naomi Kitagawa; Ryoji Muramatsu. 2019. "Life cycle CO2 emissions from power generation using hydrogen energy carriers." International Journal of Hydrogen Energy 44, no. 21: 11219-11232.
Low-carbon technologies will play a vital role in the realization of environmentally sustainable economies. However, uncertainties remain as to the feasibility of their development and implementation. Therefore, possible scenarios for the potential of these technologies should be considered to allow for flexible decision-making with respect to long-term energy strategies in Japan. This study evaluates the role of hydrogen in future energy systems in Japan using a MARKet ALlocation (MARKAL) model. A range of uncertainties are considered for nuclear power generation and carbon capture and storage (CCS) from fossil power generation. Our results suggest that an 80% reduction of CO2 emissions from the 2013 level by 2050 requires emissions from the electricity sector to decrease to nearly zero. Hydrogen power must play a functional role in future energy systems in Japan, but its contribution should depend on nuclear power and CCS.
Akito Ozawa; Yuki Kudoh; Akinobu Murata; Tomonori Honda; Itoko Saita; Hideyuki Takagi. Hydrogen in low-carbon energy systems in Japan by 2050: The uncertainties of technology development and implementation. International Journal of Hydrogen Energy 2018, 43, 18083 -18094.
AMA StyleAkito Ozawa, Yuki Kudoh, Akinobu Murata, Tomonori Honda, Itoko Saita, Hideyuki Takagi. Hydrogen in low-carbon energy systems in Japan by 2050: The uncertainties of technology development and implementation. International Journal of Hydrogen Energy. 2018; 43 (39):18083-18094.
Chicago/Turabian StyleAkito Ozawa; Yuki Kudoh; Akinobu Murata; Tomonori Honda; Itoko Saita; Hideyuki Takagi. 2018. "Hydrogen in low-carbon energy systems in Japan by 2050: The uncertainties of technology development and implementation." International Journal of Hydrogen Energy 43, no. 39: 18083-18094.
Yuki Kudoh; Akito Ozawa. Life Cycle Assessment of Hydrogen Supply Chain: A Case Study for Japanese Automotive Use. Hydrogen Supply Chains 2018, 499 -519.
AMA StyleYuki Kudoh, Akito Ozawa. Life Cycle Assessment of Hydrogen Supply Chain: A Case Study for Japanese Automotive Use. Hydrogen Supply Chains. 2018; ():499-519.
Chicago/Turabian StyleYuki Kudoh; Akito Ozawa. 2018. "Life Cycle Assessment of Hydrogen Supply Chain: A Case Study for Japanese Automotive Use." Hydrogen Supply Chains , no. : 499-519.
Akito Ozawa; Yuki Kudoh. Performance of residential fuel-cell-combined heat and power systems for various household types in Japan. International Journal of Hydrogen Energy 2018, 43, 15412 -15422.
AMA StyleAkito Ozawa, Yuki Kudoh. Performance of residential fuel-cell-combined heat and power systems for various household types in Japan. International Journal of Hydrogen Energy. 2018; 43 (32):15412-15422.
Chicago/Turabian StyleAkito Ozawa; Yuki Kudoh. 2018. "Performance of residential fuel-cell-combined heat and power systems for various household types in Japan." International Journal of Hydrogen Energy 43, no. 32: 15412-15422.
Japan needs to improve its residential energy efficiency to reduce energy consumption and thus achieve its greenhouse gas (GHG) emissions reduction targets. Understanding the differences in household behavior and energy use is important to evaluate the effect of energy conservation measures. In this study, the authors propose a new method for household energy use modeling based on questionnaire surveys on home appliances and hot water use. Fifteen-minute residential electricity and heat demand profiles with different seasons, household structures and lifestyles are obtained from the survey results, and compared with available statistical data. The replacement effects of refrigerators, TVs and lighting on residential electricity savings, net present value (NPV) and GHG reductions are evaluated using calculated energy demand. Variations in household energy use are considered under different change scenarios in household structure and by conducting an uncertainty analysis based on the Monte Carlo method. The results indicate that GHG emissions can be reduced by purchasing a new refrigerator, and electricity costs can be reduced by installing LED lamps in the living/dining room. It is also found that there is a wide range of uncertainty for NPV and GHG reductions after replacing a TV because different households watch TV for different lengths of time.
Akito Ozawa; Yuki Kudoh; Yoshikuni Yoshida. A new method for household energy use modeling: A questionnaire-based approach. Energy and Buildings 2018, 162, 32 -41.
AMA StyleAkito Ozawa, Yuki Kudoh, Yoshikuni Yoshida. A new method for household energy use modeling: A questionnaire-based approach. Energy and Buildings. 2018; 162 ():32-41.
Chicago/Turabian StyleAkito Ozawa; Yuki Kudoh; Yoshikuni Yoshida. 2018. "A new method for household energy use modeling: A questionnaire-based approach." Energy and Buildings 162, no. : 32-41.
Hydrogen is a promising energy carrier in the clean energy systems currently being developed. However, its effectiveness in mitigating greenhouse gas (GHG) emissions requires conducting a lifecycle analysis of the process by which hydrogen is produced and supplied. This study focuses on the hydrogen for the transport sector, in particular renewable hydrogen that is produced from wind- or solar PV-powered electrolysis. A life cycle inventory analysis is conducted to evaluate the Well-to-Tank (WtT) GHG emissions from various renewable hydrogen supply chains. The stages of the supply chains include hydrogen being produced overseas, converted into a transportable hydrogen carrier (liquid hydrogen or methylcyclohexane), imported to Japan by sea, distributed to hydrogen filling stations, restored from the hydrogen carrier to hydrogen and filled into fuel cell vehicles. For comparison, an analysis is also carried out with hydrogen produced by steam reforming of natural gas. Foreground data related to the hydrogen supply chains are collected by literature surveys and the Japanese life cycle inventory database is used as the background data. The analysis results indicate that some of renewable hydrogen supply chains using liquid hydrogen exhibited significantly lower WtT GHG emissions than those of a supply chain of hydrogen produced by reforming of natural gas. A significant piece of the work is to consider the impacts of variations in the energy and material inputs by performing a probabilistic uncertainty analysis. This suggests that the production of renewable hydrogen, its liquefaction, the dehydrogenation of methylcyclohexane and the compression of hydrogen at the filling station are the GHG-intensive stages in the target supply chains.
Akito Ozawa; Mai Inoue; Naomi Kitagawa; Ryoji Muramatsu; Yurie Anzai; Yutaka Genchi; Yuki Kudoh. Assessing Uncertainties of Well-To-Tank Greenhouse Gas Emissions from Hydrogen Supply Chains. Sustainability 2017, 9, 1101 .
AMA StyleAkito Ozawa, Mai Inoue, Naomi Kitagawa, Ryoji Muramatsu, Yurie Anzai, Yutaka Genchi, Yuki Kudoh. Assessing Uncertainties of Well-To-Tank Greenhouse Gas Emissions from Hydrogen Supply Chains. Sustainability. 2017; 9 (7):1101.
Chicago/Turabian StyleAkito Ozawa; Mai Inoue; Naomi Kitagawa; Ryoji Muramatsu; Yurie Anzai; Yutaka Genchi; Yuki Kudoh. 2017. "Assessing Uncertainties of Well-To-Tank Greenhouse Gas Emissions from Hydrogen Supply Chains." Sustainability 9, no. 7: 1101.
Residential smart metering and energy feedback have attracted worldwide attention toward reducing energy consumption and building a sustainable society. Many theoretical studies have suggested the importance of personalized information; however, few feedback demonstrations have focused on household lifestyle. This paper presents a pilot program of energy feedback reports based on analytical methods to show the relationship between electricity consumption and household lifestyle in Japan. One type of report was for households with a night-oriented lifestyle, which were classified by means of frequency analysis; it was evident that such households should shift to a healthy, environmentally friendly, morning-oriented lifestyle. Another type of report was based on cluster analysis: it pinpointed the dates and times when the household consumed much more electricity than with its regular routine. Through panel data regression analysis, it was found that the reports contributed to reducing daily household electricity consumption—as long as a boomerang effect could be avoided. It was also found that the feedback effect was enhanced by activation of consciousness, norms, and motives. It was observed that activation required a good understanding of the characteristics of electricity consumption and lifestyles of each household.
Akito Ozawa; Ryota Furusato; Yoshikuni Yoshida. Tailor-Made Feedback to Reduce Residential Electricity Consumption: The Effect of Information on Household Lifestyle in Japan. Sustainability 2017, 9, 528 .
AMA StyleAkito Ozawa, Ryota Furusato, Yoshikuni Yoshida. Tailor-Made Feedback to Reduce Residential Electricity Consumption: The Effect of Information on Household Lifestyle in Japan. Sustainability. 2017; 9 (4):528.
Chicago/Turabian StyleAkito Ozawa; Ryota Furusato; Yoshikuni Yoshida. 2017. "Tailor-Made Feedback to Reduce Residential Electricity Consumption: The Effect of Information on Household Lifestyle in Japan." Sustainability 9, no. 4: 528.
Akito Ozawa; Ryota Furusato; Yoshikuni Yoshida. Determining the relationship between a household’s lifestyle and its electricity consumption in Japan by analyzing measured electric load profiles. Energy and Buildings 2016, 119, 200 -210.
AMA StyleAkito Ozawa, Ryota Furusato, Yoshikuni Yoshida. Determining the relationship between a household’s lifestyle and its electricity consumption in Japan by analyzing measured electric load profiles. Energy and Buildings. 2016; 119 ():200-210.
Chicago/Turabian StyleAkito Ozawa; Ryota Furusato; Yoshikuni Yoshida. 2016. "Determining the relationship between a household’s lifestyle and its electricity consumption in Japan by analyzing measured electric load profiles." Energy and Buildings 119, no. : 200-210.
Akito Ozawa; Yoshikuni Yoshida. Economic and Environmental Effects of Installing Distributed Energy Resources into a Household. Low Carbon Economy 2015, 06, 41 -50.
AMA StyleAkito Ozawa, Yoshikuni Yoshida. Economic and Environmental Effects of Installing Distributed Energy Resources into a Household. Low Carbon Economy. 2015; 06 (02):41-50.
Chicago/Turabian StyleAkito Ozawa; Yoshikuni Yoshida. 2015. "Economic and Environmental Effects of Installing Distributed Energy Resources into a Household." Low Carbon Economy 06, no. 02: 41-50.