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With the world population growth, energy consumption and the rapid development of industrial economy, a large amount of carbon emissions has brought destruction and threats to the earth's environment on which human beings depend. The development of low-carbon economy has become the consensus of governments all over the world and has been vigorously advocated & promoted. This paper focuses on the top five global GDP nations in 2022: The United States, China, Japan, Germany, and Britain. A comprehensive evaluation index system of urban low-carbon economic development level is constructed from four dimensions: economic development level, environmental quality, energy consumption emission intensity and social development speed by using literature review and field interview. The evaluation measures are determined using the TOPSIS evaluation method with entropy weight and the grey relational model, providing a comprehensive assessment of the low-carbon economy's development level in these five countries." Judging from the comprehensive evaluation score, the overall development of low-carbon economy in American cities is in good condition and has reached the development standard of low-carbon economy; Germany and Japan rank second and third, and they are low-carbon economies. Britain ranks fourth in comprehensive evaluation, although it belongs to a low-carbon economy country, but there is still a certain gap with Germany and Japan; There is still a big gap between China and the other four countries. Based on the measurement and evaluation outcomes, it presents recommendations and strategies to foster the growth of low-carbon economies, offering valuable insights for the advancement of such economies across different nations. The research results guide countries all over the world to reduce carbon emissions in the process of economic development, protect the earth environment on which human beings depend, and make a better tomorrow for sustainable development. [ABSTRACT FROM AUTHOR]

With regard to environmental degradation in Japan, the world's third-largest economy, limited studies have been performed to illustrate the ecological aspects of the country's core and recent economic policies such as globalization, technological innovation, and renewable energy usage policies. Given this motivation, this research reveals a new perspective on the connection between CO2 emissions and GDP growth, renewable energy, technological innovation and globalization in Japan by employing wavelet statistical tools. The paper employs series of wavelet tools for datasets covering the period from 1990Q1 to 2015Q4. The empirical outcomes demonstrate proof of the interaction between renewable energy use, economic growth, technological innovation, globalization and CO2 emissions in both time and frequency. The empirical results of the wavelet analyses reveal that globalization, GDP growth, and technological innovation increase CO2 emissions in Japan, while renewable energy usage mitigates CO2 in the short and medium terms. The results demonstrate the significance of implementing policies effectively coordinated by the policymakers to curb the significant environmental degradation in Japan. Moreover, Japan should actively support renewable energy development and create a more competitive climate for investment in the renewable energy market. [ABSTRACT FROM AUTHOR]

Densely built areas with poor thermal insulation suffer from high thermal environmental risks and generally consume high energy in summer. Determining the relationship between density and energy consumption is necessary, particularly when implementing urban heat island (UHI) countermeasures. This study evaluated the effects of density and UHI countermeasures on the energy consumption and indoor thermal comfort of a detached house in a typical densely built wooden house area in Yokohama City, Japan. Three densities and six countermeasures were considered. Annual hourly simulations based on the SCIENCE-Vent thermal environment simulation model yielded the following results: in densely built wooden house areas, the energy consumption and thermal discomfort increased with density. The green roof yielded the largest energy savings in the cooling and heating seasons, demonstrating the highest annual energy savings with 5.7%. Density had little impact on rooftop countermeasures, but the effect of the high-reflectance walls increased with density, and the reduction in annual energy consumption (air conditioning and lighting) is 2.6%, 3.0%, 3.6% in 37%, 47%, and 59% density cases, respectively. The impact of thermal countermeasures on indoor thermal comfort varied according to the thermal control mechanism. [ABSTRACT FROM AUTHOR]

This study evaluates the progress of efficient energy use and the control of carbon dioxide (CO2) emissions in Japan between 1990 and 2012. A new indicator of energy performance is presented called environmental energy efficiency (EEE). The EEE of manufacturing industries was measured by each prefecture in Japan. We estimated the influencing factors of EEE for each industry by applying the pooled mean group (PMG) method. Our findings are as follows: First, the Japanese manufacturing industry has not been in line with the EEE improvement goals since the adoption of the Kyoto Protocol. However, the progress of each industry was relatively consistent by region. Second, EEE tends to improve and then deteriorate or monotonically increase as economic development progresses. Third, EEE is raised by expanding industry share. Finally, EEE, which focuses on energy reduction, is likely to increase with the progress of energy-saving technology. [ABSTRACT FROM AUTHOR]

Japan is regarded as an interesting source for drawing useful lessons that could help in drafting the process for transforming the Polish energy mix. The reason is very simple: the two countries have relatively similar starting points. A large proportion of the Japanese energy mix is still based on fossil fuels. We can already observe a slow but evident drift away from fossil fuels (from some 85% in 2013 to less than 75% in 2019). Another reason why Japan is relevant to the Polish conditions is the recent decision of the new government in Japan to return to nuclear energy after the Fukushima disaster. Other interesting solutions in the Japanese way forward include the wide use of hydrogen and ammonia; that could be interesting for Poland, because it is a major producer of hydrogen: the fifth in the world and the third in Europe. Grey hydrogen is currently produced, but that could easily be transformed into green hydrogen produced using distributed solar installations. It also seems that nobody in Poland is seriously working on the use of ammonia in the energy sector. Those reasons alone would be enough to choose Japan as the country for the analysis presented below, therefore the literature review is limited to the Japanese sphere. A short historical view of the energy-mix configuration is followed by an enumeration of the important aspects to consider for Polish conditions: energy security and energy efficiency, followed by an analysis of important sources of energy: nuclear, renewable energy sources (RES), hydrogen, and ammonia as well as thermal power development. [ABSTRACT FROM AUTHOR]

CO2 emissions associated with hydrogen production can be reduced replacing steam methane reforming with electrolysis using renewable electricity with a trade-off of increasing energy consumption, water consumption and cost. In this research, a linear programming optimization model of a hydrogen production system that considers simultaneously energy consumption, water consumption, CO2 emissions and cost on a cradle-to-gate basis was developed. The model was used to evaluate the impact of CO2 intensity on the optimum design of a hydrogen production system for Japan considering different stakeholders' priorities. Hydrogen is produced using steam methane reforming and electrolysis. Electricity sources include grid, wind, solar photovoltaic, geothermal and hydro. Independent of the stakeholders' priorities, steam methane reforming dominates hydrogen production for cradle-to-gate CO2 intensities larger than 9 kg CO2/kg H2, while electrolysis using renewable electricity dominates for lower cradle-to-gate CO2 intensities. Reducing the cradle-to-gate CO2 intensity increases energy consumption, water consumption and specific cost of hydrogen production. For a cradle-to-gate CO2 intensity of 0 kg CO2/kg H2, the specific cost of hydrogen production varies between 8.81 and 13.6 USD/kg H2; higher than the specific cost of hydrogen production targeted by the Japanese government in 2030 of 30 JPY/Nm3, 3.19 USD/kg H2. [ABSTRACT FROM AUTHOR]

Windows are among building components that have the strongest effect on thermal load. They play a significant role in heat loss in buildings because they usually have a largely higher thermal conductance than other components of the building envelope. Although many studies have highlighted the relevance of heat transfer through frames and aimed to improve their thermal performance, poorly insulated aluminum frames (thermal conductivity of aluminum is 160 W/m·K, while that of polyvinyl chloride [PVC] is 0.17 W/m·K) are still in use in Japan. Therefore, the U-values of different window frames were calculated, and annual thermal loads were calculated according to the window configurations, including the frame, glazing, and cavity. We focused on standard residential buildings in Japan with a total floor area of 120.6 m2 (two-story building), and the number of newly built houses and the application rate of window configurations in 2019 were surveyed to estimate the CO2 emissions by regions. CO2 emissions were reduced by approximately 3.98–6.58% with the application of PVC frames. Furthermore, CO2 emissions were converted into the amount of CO2 gas absorbed by cedar trees, which cover nearly 18% of the total land area of Japan. In conclusion, analogous to the amount of CO2 gas absorbed by cedar trees, the absorption effect was equivalent to 327,743–564,416 cedar trees. Changing the window frame material can facilitate a significant energy-saving effect as a considerable amount of energy is saved, especially at a city scale. [ABSTRACT FROM AUTHOR]

Electric bidets have become widespread in Japan and are now rapidly being installed across the rest of Asia, the United States, and the European Union. However, the impact on water infrastructure has not yet been sufficiently evaluated. Using Japan as an example, we assess the impact of the spread of electric bidets on the existing water infrastructure and use the results to predict the impact in countries in which the spread of electric bidets is expected in the future. In this study, we first proposed a model of electric bidet use on the basis of the results of a questionnaire survey. In Japan, the frequency of electric bidet use is considered to be the same as that of toilet use, and this model is used by the Ministry of Economy, Trade and Industry (METI) in its official evaluation of equipment performance. However, in this survey, we found that 30–40% of respondents did not use electric bidets, even though they have become commonplace in Japan. The reason for this was a vague sense of anxiety about sanitation. Based on the results of the survey, the model for electric bidet use was set to once a day for men for flushing following defecation and once a day for women for either flushing following defecation or bidet flushing. This is considerably less frequent than the conventional Japanese electric bidet use model for women, which models for one flush following defecation and three flushes following urination. Japan's Energy Conservation Law requires improved energy efficiency in 32 items of equipment, of which the electric bidet is one. Because of this regulation, the electricity consumption of electric bidets has decreased by one fourth in the past 10 years. When a new model representing actual usage was applied, the environmental impact of the electric bidets currently sold was shown to be minimal. [ABSTRACT FROM AUTHOR]

In earthquake engineering, acceleration has played a major role, while wave energy has rarely been considered as a demand in design. In order to understand earthquake damage mechanism in terms of energy, the demand in terms of wave energy in surface soil layers is studied here, assuming one-dimensional SH wave propagation by using a number of vertical array records during nine strong earthquakes in Japan. A clear decreasing trend of the energy demand with decreasing ground depth and decreasing surface soil stiffness has been found as well as a propensity of incident energies calculated at bedrocks being roughly compatible with empirical formulas. How the energy demand is correlated with structural damage is also discussed in simplified models to show that induced structural strain is governed by upward energy flux, degree of structural resonance, and impedance ratio between structure and ground and structural stiffness. In low-damping brittle superstructures, wave energy flux in resonance and associated predominant frequency are decisive in determining the damage, while cumulative wave energy determines the damage in high damping ductile soil and massive concrete structures. The trend of lower energy demand in softer soil sites may not be contradictory, with a widely accepted perception that softer soil sites tend to suffer heavier earthquake damage as far as geotechnical damage is concerned. [ABSTRACT FROM AUTHOR]

Based on the strong similarities between energy-resource-poor and fossil-fuel-centered economies (e.g., Taiwan, Japan, and South Korea) in terms of economy, culture, and energy usage characteristics, they should be analyzed collectively. This study adopted two-tier input-output structural decomposition analysis to identify the driving forces behind CO2 emissions to these countries to the formulation of effective environmental policy. Data from the World Input-Output Database was used to decompose relative changes in CO2 emissions into a range of technological advances, factor substitution, and final demand effects. Technological advances in energy (direct) contributed to a 77% reduction in Taiwan and a 34% reduction in South Korea. This is a clear indication that improving energy efficiency via technological advances should be a priority. In Japan in particular, there was a 22% reduction in CO2 emissions attributable to technological advances in materials; hence, it is recommended that Taiwan and South Korea work to extensively develop eco-industrial parks to create industry clusters to promote resource/energy efficiency and reductions in CO2 emissions. Decomposition results based on factor substitution revealed that a variety of strategies will be required, such as switching to fuels that are less carbon intensive, promoting the adoption of renewable energies, and implementing clean-coal technologies. [ABSTRACT FROM AUTHOR]