This paper describes the effectiveness of a residential fuel cell combined heat and power (CHP) system for cold regions for energy conservation. Residential CHP system has attracted attention for its high energy saving and environmental performance, and systems using gas engines and fuel cells have recently been introduced into the market in Japan. In Hokkaido as a cold region, high energy demand exists, which causes a large amount of CO₂ emissions and energy consumption compared to national average. Under such circumstances, we conducted demonstration tests of 4 residential fuel cell systems in Sapporo, and compared with the results in non-cold regions. According to the data of demonstration tests, contribution rate of supplied power of fuel cell systems are higher than the national average. The amount of reduction in primary energy was 1.3 to 3.4 MWh/year compared with the conventional type (commercial power + non-condensing boiler). And the figures are higher than the results of the residences in non-cold regions which have comparable energy consumption. Results of multiple linear regression analysis, the amount of reduction in primary energy correlate highly with electric demand and domestic hot water demand.

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This paper presents the evidence of power demand reduction measures during the summer peak-time, including the Advice Report designed by authors, which incorporates a variety of behavior-scientific intelligence. Through the randomized experiment targeted on the almost 230 residents in a condominium receiving high-voltage collective power, we evaluated the average treatment effects (ATEs) of (1) the increasing tariff based on instantaneous electricity usage (kW), (2) the visualization of actual electricity usage on In-Home Display, (3) the Advice Report, and (4) the email alert to curtail the electricity usage during the grid peak-time. The total ATE of these measures was 11.1% on the grid peak- time, 8.7% on the peak-time of the targeted condominium, and 6.9% whole day. In addition, questionnaire survey results also showed the analogous trends, such as the fact that the households receiving the measures had significantly higher level of consciousness on peak-time electricity conservation than the others. Though the results were not statistically significant, it suggested the general trends of the effectiveness of each measure.

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The study was undertaken to analysis area energy network in cases of introducing both gas engine cogeneration systems and energy networks for an actual industrial park. A smart energy network is an energy network combining distributed power sources optimally with the large-scale infrastructure of an electric power network and steam network. Energy data of three factories obtained from interviews were classified into those of hot water, heating, cooling, and electric power. The authors used the CASCADE based on spreadsheet software. This study investigated five simulation cases. Energy saving was 29.2 % compared with the reference systems. The ratio of energy saving to demand reached 19.2 % compare with the cogeneration system. A gas engine was introduced more intensively into factory in the plant scale with electric power selling than in the area energy network. It is necessary to consider the generation efficiency and exhaust heat use rate by the partial load characteristic for expansion of cogeneration system. These simulation results are very useful for suggesting new roles of the new energy demand and supply systems in industry sector of the future.

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Energy consumption on hot water occupies 27.7 % of energy consumption in residential dwellings in Japan. Optimum operation of high efficient technologies such as combined heat and power systems or renewable energies, and encouragement of residents’ behavior to conserve energy are necessary to reduce energy consumption. Detailed data on end-use consumption of hot water is needed to develop optimum operation and analyze on residents’ behavior.
However, only few studies have been reported on hot water consumption, and detailed end-use consumption data has not been available. The electricity, city gas, and hot water consumption of six residential households were measured every two seconds in Osaka City for a period of four years. Detailed hot water consumption was measured directly by flow sensors and thermocouples. The consumption data was divided to end-use, bathtub filling, reheat of bathtub, and other such as shower or kitchen. The measured data was analyzed on the differences between households, the relationship to ambient temperature, and water consumption in relation to patterns of bathtub use. The frequency of bathtub use varies between households and seasons, and the use of the bathtub is one of the most significant factors in hot water consumption in residential dwellings.

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Japan’s long-term mitigation target in 2050 is to reduce GHG emission by 80% compared to 1990 level. However, after the Fukushima Daiichi Nuclear Power Plant accident in 2011, availability of nuclear power in the future becomes uncertain. Complying with the discussion about Japan’s new energy policy, nuclear power may phase out toward 2050. This study is intended to estimates a feasibility to achieve 80% reduction target without nuclear power, by using multi-regional end-use model in Japan.
The model is developed based on AIM/Enduse Model and divided into 10 regions which are consistent with Japan’s 10 major electric power company’s distribution area. The regional characteristics such as renewable energy potential and climate condition are reflected in the model. In this study, current electricity interconnection capacity limit among 10 regions, and reinforcement of interconnection as a countermeasure are also considered.
As a result, without nuclear power, carbon price to achieve 80% reduction by 2050 will be up to 51,000yen/tCO₂ in 2050. However, if reinforcing interconnection is available, carbon price is reduced by up to 5%. To compensate for the phase-out of nuclear power, not only implementation of energy efficiency or renewable but system technology such as reinforcing electricity interconnection is substantially important.

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Exacerbation of water stress is a critical issue for sustainable development of human society. This study analyzes the change in water stress during this century based on the annual water withdrawal-to-availability ratio, and contributions of major causes to the change, for each of the global river basins under different socioeconomic development and climate change scenarios. Examples of the results are as follows: The stress will increase in 58%-62% of the world river basin areas until around 2030, as a result of population growth and the increase in per capita municipal and industrial water withdrawals. On the other hand, the stress will decrease in 5% of such areas due to different reasons by region. In the Huang He river basin, which is currently threatened by high water stress, the stress is expected to increase until around 2030 mainly due to population growth, and to decrease drastically thereafter due to an increase in water availability and a decrease in per capita agricultural water withdrawal associated with climate change. Measures in the water management until around 2030 will be significant in this river basin; and considerations of uncertainties in climate change will be important in a planning of measures for after 2030, because the climate change influences both water availability and agricultural water withdrawal.

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Residential energy use feedback has been considered an effective form of intervention to promote conservation behavior among households. HEMS (home energy management system) display is a good opportunities for making energy consumption more visible and for engaging individuals in more thoughtful energy use practices. The purpose of this paper is to investigate the long-term effect of residential energy use feedback with HEMS and designed to examine the HEMS browsing behavior and to ensure negative effects that derive from “wear-out”. In total, 463 households responded to a questionnaire survey that had been carried out at July 2013 and January 2014, all the respondent lives in newly built detached house equipped with HEMS and roof-top PV.
Research findings suggest that HEMS browsing behaviors tend to fall into six distinct groups and that the types of browsing behaviors engaged in by households tends to correspond to the level of attitude or intention to energy saving behavior. Also we found that wear-out effects had been occurred to some of the residents and follow-up services after HEMS installed would be important on keeping residents engaged in educated on ways to reduce energy use.

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