Prediction of greenhouse gas reduction potential in Japanese residential sector by residential energy end-use model

A model is developed that simulates nationwide energy consumption of the residential sector by considering the diversity of household and building types. Since this model can simulate the energy consumption for each household and building category by dynamic energy use based on the schedule of the occupants’ activities and a heating and cooling load calculation model, various kinds of energy-saving policies can be evaluated with considerable accuracy. In addition, the average energy efficiency of major electric appliances used in the residential sector and the percentages of housing insulation levels of existing houses is predicted by the “stock transition model.” In this paper, energy consumption and CO₂ emissions in the Japanese residential sector until 2025 are predicted. For example, as a business – as-usual (BAU) case, CO₂ emissions will be reduced by 7% from the 1990 level. Also evaluated are mitigation measures such as the energy efficiency standard for home electric appliances, thermal insulation code, reduction of standby power, high-efficiency water heaters, energy-efficient behavior of occupants, and dissemination of photovoltaic panels.     

Life-cycle analysis of greenhouse gas emission and energy efficiency of hydrogen fuel cell scooters

The well-to-wheels (WTW) analysis of energy conservation and greenhouse gas emission of advanced scooters associated with new transportation fuels is studied in the present work. Focus is placed on fuel cell scooter technologies, while the gasoline-powered scooter equipped with an internal combustion engine (ICE) serves as a reference technology. The effect of various pathways of hydrogen production on the well-to-tank (WTT) efficiency for energy is examined. Both near-term and long-term hydrogen production options are explored, such as purification of coke oven gas (COG), steam reforming of natural gas, water electrolysis by generation mix and renewable electricity, and gasification of herbaceous biomass. Then, the WTW efficiency of fuel cell scooters for various hydrogen production options is compared with that of the conventional ICE scooters and electric scooters. Results showed that the fuel cell scooters fueled with COG-based hydrogen could achieve the highest reduction benefits in energy consumption and GHG emission. Finally, the potential for hydrogen production from COG resulting from the coking process in steelworks is evaluated, which is anticipated as a near-term hydrogen production for helping transition to a hydrogen energy economy in Taiwan.     

In search of a sustainable hydrogen economy: How a large-scale transition to hydrogen may affect the primary energy demand and greenhouse gas emissions

This paper reveals assessments made by a pan-European strategic project entitled HySociety (2003–2005), in which political, societal and technical challenges for developing a European hydrogen economy were addressed [Hetland J/SINTEF, editor, Task 2.3 D17. Set of actions to be taken at European level for the hydrogen society infrastructure. HySociety. Scientific report to be published on 〈$〈$www.hysociety.net〉$〉$, 2005]. From this work it has become evident that fossil fuels represent the most competitive option for hydrogen supply over the foreseeable future. Therefore it is mandatory to manage the reserves in a most sustainable way. The continued dependency of fossil fuels raises geopolitical issues of growing concern. Strategic questions pertaining to hydrogen energy are the prerequisites for supply versus the primary energy demand, greenhouse gas emissions and cost expectation in which hydrogen and fuel cells should be looked at in a broader context.     

Life-cycle analysis of greenhouse gas emissions from hydrogen delivery: A cost-guided analysis

The cost of hydrogen delivery for transportation accounts for most of the current H₂ selling price; delivery also requires substantial amounts of energy. We developed harmonized techno-economic and life-cycle emissions models of current and future H₂ production and delivery pathways. Our techno-economic analysis of dispensed H₂ costs guided our selection of pathways for the life-cycle analysis. In this paper, we present the results of market expansion scenarios using existing capabilities (for example, those that use H₂ from steam methane reforming, chlor-alkali, and natural gas liquid cracker plants), as well as results for future electrolysis plants that use nuclear, solar, and hydroelectric power. Reductions in greenhouse gas emissions for fuel cell electric vehicles compared to conventional gasoline pathways vary from 40% reduction for fossil-derived H₂ to 20-fold for clean H₂. Supplemental tables with greenhouse gas emissions data for each step in the H₂ pathways enable readers to evaluate additional scenarios.     

Blending blue hydrogen with natural gas for direct consumption: Examining the effect of hydrogen concentration on transportation and well-to-combustion greenhouse gas emissions

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H₂ fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H₂ and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H₂ is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emissions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50–100 million m³/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO₂-free scenario. While hythane contains 15% H₂ by volume only 5% of the gas’ energy comes from H₂, limiting its GHG benefit.     

Sectoral trends in global energy use and greenhouse gas emissions

Integrated assessment models have been used to project both baseline and mitigation greenhouse gas emissions scenarios. Results of these scenarios are typically presented for a number of world regions and end-use sectors, such as industry, transport, and buildings. Analysts interested in particular technologies and policies, however, require more detailed information to understand specific mitigation options in relation to business-as-usual trends. This paper presents sectoral trend for two of the scenarios produced by the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios. Global and regional historical trends in energy use and carbon dioxide emissions over the past 30 years are examined and contrasted with projections over the next 30 years. Macro-activity indicators are analyzed as well as trends in sectoral energy and carbon demand. This paper also describes a methodology to calculate primary energy and carbon dioxide emissions at the sector level, accounting for the full energy and emissions due to sectoral activities.     

Modeling California policy impacts on greenhouse gas emissions

This paper examines policy and technology scenarios in California, emphasizing greenhouse gas (GHG) emissions in 2020 and 2030. Using CALGAPS, a new, validated model simulating GHG and criteria pollutant emissions in California from 2010 to 2050, four scenarios were developed: Committed Policies (S1), Uncommitted Policies (S2), Potential Policy and Technology Futures (S3), and Counterfactual (S0), which omits all GHG policies. Forty-nine individual policies were represented. For S1–S3, GHG emissions fall below the AB 32 policy 2020 target [427 million metric tons CO₂ equivalent (MtCO₂e) yr⁻¹], indicating that committed policies may be sufficient to meet mandated reductions. In 2030, emissions span 211–428 MtCO₂e yr⁻¹, suggesting that policy choices made today can strongly affect outcomes over the next two decades. Long-term (2050) emissions were all well above the target set by Executive Order S-3-05 (85 MtCO₂e yr⁻¹); additional policies or technology development (beyond the study scope) are likely needed to achieve this objective. Cumulative emissions suggest a different outcome, however: due to early emissions reductions, S3 achieves lower cumulative emissions in 2050 than a pathway that linearly reduces emissions between 2020 and 2050 policy targets. Sensitivity analysis provided quantification of individual policy GHG emissions reduction benefits.     

Benchmarking energy use and greenhouse gas emissions in Singapore’s hotel industry

Hotel buildings are reported in many countries as one of the most energy intensive building sectors. Besides the pressure posed on energy supply, they also have adverse impact on the environment through greenhouse gas emissions, wastewater discharge and so on. This study was intended to shed some light on the energy and environment related issues in hotel industry. Energy consumption data and relevant information collected from hotels were subjected to rigorous statistical analysis. A regression-based benchmarking model was established, which takes into account, the difference in functional and operational features when hotels are compared with regard to their energy performance. In addition, CO₂ emissions from the surveyed hotels were estimated based on a standard procedure for corporate GHG emission accounting. It was found that a hotel’s carbon intensity ranking is rather sensitive to the normalizing denominator chosen. Therefore, carbon intensity estimated for the hotels must not be interpreted arbitrarily, and industry specific normalizing denominator should be sought in future studies.     

Energy demand and greenhouse gas emissions from urban passenger transportation versus availability of renewable energy: The example of the Canadian Lower Fraser Valley

The energy consumption and greenhouse gas emissions of all private and transit vehicles from the Lower Fraser Valley, British Columbia, Canada are analysed for the year 2000. The energy figures are then compared with the Province's renewable energy potential. Results indicate that electric trolley buses and the automated rapid transit SkyTrain were eight times as energy efficient as private vehicles. These two modes were also 100 times as emission efficient as private vehicles in terms of greenhouse gas emitted per passenger-kilometer. Analysis of a minimal greenhouse gas emissions scenario, based on local renewable energy resources, electrolytic hydrogen production, and conversion of all private vehicles to fuel-cell technology indicates that such a strategy would utilize between 40% and 60% of the Province's renewable energy resources. We conclude that, if the use of renewable energy resources is chosen to reduce emissions from urban passenger transportation, probability of success will be increased by reducing the sector's energy demand through a transfer of ridership to the most energy efficient modes.     

Reduce energy use and greenhouse gas emissions from global dairy processing facilities

Global butter, concentrated milk, and milk powder products use approximately 15% of annual raw milk production. Similar to cheese and fluid milk, dairy processing of these products can be energy intensive. In this paper, we analyzed production and energy data compiled through extensive literature reviews on butter, concentrated milk, milk and whey powder processing across various countries and plants. Magnitudes of national final and primary specific energy consumption (SEC) exhibited large variations across dairy products; in addition, the final SEC of individual plants and products exhibited significant variations within a country and between countries. Furthermore, we quantified national energy intensity indicators (EIIs) accounting for dairy product mixes and technological advancement. The significant variations of SEC and EII values indicate a high degree of likelihood that there is significant potential for energy savings in the global dairy processing industry. Based upon the study samples, we estimate potential energy savings for dairy processing industry in selected countries, and estimates annual reduction of 9–14 million metric-ton carbon-equivalent¹ could be achieved if measures are implemented to lower SEC values by 50–80% in half of global dairy plants. The paper calls for publication of more energy data from the dairy processing industry.     

Greenhouse gas emissions assessment of hydrogen and kerosene-fueled aircraft propulsion

The paper highlights the importance of hydrogen as a promising alternative for future aircraft fuel, with respect to reduced environmental impact, increased sustainability, high energy content and favorable combustion kinetics, since the rapid growth and dependence of aircraft propulsion on fossil fuels are unsustainable. This paper compares the environmental impact of hydrogen and kerosene-fueled aircraft, in terms of greenhouse gas emissions and other emission comparisons. Sample flights from Toronto to Montreal, and Calgary to London are examined. Emissions from a conventional aircraft are estimated and compared with the LH₂ (liquid hydrogen) aircraft. The environmental benefits and drawbacks of these systems are presented from safety and storage perspectives. Radiative forcing factors that compare conventional aircraft and LH₂ aircraft are included. It is shown that the amount of NO_x, HC and CO emissions for the trips with conventional aircraft for Calgary is 171.4, 41.9 and 32.2 kg, while Montreal is 56.17, 2.43 and 21.9 kg, and London is 251.7, 5.1 and 39.2 kg, respectively. These results are compared against hydrogen propulsion to show the promising capabilities of hydrogen as an aircraft fuel.     

Energy saving potential in the residential sector of Uzbekistan

In 2003, the residential sector of Uzbekistan has consumed about 15.073 Mtoe (million ton of oil equivalent) of energy or 27.3% of the total energy consumed in the country. This value is approximately twice as much as that of residential sector of Turkey and Romania. The climate of above countries is comparable to that of Uzbekistan. In this article we suggest to use the heating degree-day method for determining the natural gas consumption norms for residential heating. Taking the climatic differences into account, the norms of natural gas consumption in respect to each resident are submitted for each region of Uzbekistan. The realization of suggested proposals allows saving about 9.2 billion m³ of natural gas annually.     

Comparison of the technical potential for hydrogen,battery electric,and conventional light-duty vehicles to reduce greenhouse gas emissions and petroleum consumption in the United States

Light-duty vehicles (LDV) are responsible for a large fraction of petroleum use and are a significant source of greenhouse gas (GHG) emissions in the United States. Improving conventional gasoline-powered vehicle efficiency can reduce petroleum demand, however efficiency alone cannot reach deep GHG reduction targets, such as 80% below the 1990 LDV GHG emissions level. Because the cost and availability of low-GHG fuels will impose limits on their use, significant reductions in GHG emissions will require combinations of fuel and vehicle technologies that both increase efficiency and reduce the emissions from fuel production and use. This paper examines bounding cases for the adoption of individual technologies and then explores combinations of advanced vehicle and fuel technologies. Limits on domestic biofuel production—even combined with significant conventional combustion engine vehicle improvements—mean that hydrogen fuel cell electric or battery electric vehicles fueled by low-GHG sources will be necessary. Complete electrification of the LDV fleet is not required to achieve significant GHG reduction, as replacing 40% of the LDV fleet with zero-emission hydrogen vehicles while achieving optimistic biofuel production and conventional vehicle improvements can allow attainment of a low GHG emission target. Our results show that the long time scale for vehicle turnover will ensure significant emissions from the LDV sector, even when lower emission vehicles and fuels are widely available within 15 years. Reducing petroleum consumption is comparatively less difficult, and significant savings can be achieved using efficient conventional gasoline-powered vehicles.     

Life cycle analysis of energy use and greenhouse gas emissions for road transportation fuels in China

Life cycle analysis is considered to be a valuable tool for decision making towards sustainability. Life cycle energy and environmental impact analysis for conventional transportation fuels and alternatives such as biofuels has become an active domain of research in recent years. The present study attempts to identify the most reliable results to date and possible ranges of life cycle fossil fuel use, petroleum use and greenhouse gas emissions for various road transportation fuels in China through a comprehensive review of recently published life cycle studies and review articles. Fuels reviewed include conventional gasoline, conventional diesel, liquefied petroleum gas, compressed natural gas, wheat-derived ethanol, corn-derived ethanol, cassava-derived ethanol, sugarcane-derived ethanol, rapeseed-derived biodiesel and soybean-derived biodiesel. Recommendations for future work are also discussed.     

Life-cycle energy consumption and greenhouse gas emissions for electricity generation and supply in China

The Well-to-Meter (WTM) analysis module in the Tsinghua-CA3EM model has been used to examine the primary fossil energy consumption (PFEC) and greenhouse gas (GHG) emissions for electricity generation and supply in China. The results show that (1) the WTM PFEC and GHG emission intensities for the 2007 Chinese electricity mix are 3.247 MJ/MJ and 297.688 g carbon dioxide of equivalent (gCO_2,e)/MJ, respectively; (2) power generation is the main contributing sub-stage; (3) the coal-power pathway is the only major contributor of PFEC (96.23%) and GHG emissions (97.08%) in the 2007 mix; and (4) GHG emissions intensity in 2020 will be reduced to 220.470 gCO_2,e/MJ with the development of nuclear and renewable energy and to 169.014 gCO_2,e/MJ if carbon dioxide capture and storage (CCS) technology is employed. It is concluded that (1) the current high levels of PFEC and GHG emission for electricity in China are largely due to the dominant role of coal in the power-generation sector and the relatively low efficiencies during all the sub-stages from resource extraction to final energy consumption and (2) the development of nuclear and renewable energy as well as low carbon technologies such as CCS can significantly reduce GHG emissions from electricity.     

Long-term energy savings and greenhouse gas emission reductions in the Swiss residential sector

The aim of this paper is to explore the possibilities to reach two long-term targets regarding energy consumption and greenhouse gas emissions of the Swiss residential building stock: a reduction of the final energy consumption by a factor of 3 and of _CO2${\mathrm{CO}}_2$ emissions by a factor of 5 until 2050. A model is constructed to describe the dynamics of the energy-relevant properties of the residential building stock. Appropriate scenarios are discussed in terms of decisions made during construction or renovation of residential buildings which affect heat demand and determine the energy carriers used for heating and hot water generation. We show that both targets could be reached, although ambitious efforts are necessary. The central element of a successful strategy is to reduce the specific heat demand of existing buildings during renovation and to substitute the heating and hot water systems by less carbon intensive ones. Our results suggest that there is more flexibility to reach the emission target than the energy reduction target.     

Structural decomposition analysis of Australia's greenhouse gas emissions

A complex system of production links our greenhouse gas emissions to our consumer demands. Whilst progress may be made in improving efficiency, other changes in the production structure may easily annul global improvements. Utilising a structural decomposition analysis, a comparative-static technique of input–output analysis, over a time period of around 30 years, net greenhouse emissions are decomposed in this study into the effects, due to changes in industrial efficiency, forward linkages, inter-industry structure, backward linkages, type of final demand, cause of final demand, population affluence, population size, and mix and level of exports.Historically, significant competing forces at both the whole of economy and industrial scale have been mitigating potential improvements. Key sectors and structural influences are identified that have historically shown the greatest potential for change, and would likely have the greatest net impact. Results clearly reinforce that the current dichotomy of growth and exports are the key problems in need of address.     

Reducing greenhouse gas emissions by inducing energy conservation and distributed generation from elimination of electric utility customer charges

This paper quantifies the increased greenhouse gas emissions and negative effect on energy conservation (or “efficiency penalty”) due to electric rate structures that employ an unavoidable customer charge. First, the extent of customer charges was determined from a nationwide survey of US electric tariffs. To eliminate the customer charge nationally while maintaining a fixed sum for electric companies for a given amount of electricity, an increase of 7.12% in the residential electrical rate was found to be necessary. If enacted, this increase in the electric rate would result in a 6.4% reduction in overall electricity consumption, conserving 73 billion kW h, eliminating 44.3 million metric tons of carbon dioxide, and saving the entire US residential sector over $8 billion per year. As shown here, these reductions would come from increased avoidable costs, thus leveraging an increased rate of return on investments in energy efficiency, energy conservation behavior, distributed energy generation, and fuel choices. Finally, limitations of this study and analysis are discussed and conclusions are drawn for proposed energy policy changes.     

Marginal abatement costs of greenhouse gas emissions: A meta-analysis

In this paper, we carry out a meta-analysis of recent studies into the costs of greenhouse gas mitigation policies that aim at the long-term stabilisation of these gases in the atmosphere. We find the cost estimates of the studies to be sensitive to the stringency of the stabilisation target, the assumed emissions baseline, the way in which the time profile of emissions is determined in the model, the choice of control variable (CO₂ only versus multigas), the number of regions and energy sources in the model and, to a lesser degree, the scientific “forum” in which the study was developed. We find that marginal abatement costs of the stringent long-term targets that are currently considered by the European Commission are still very uncertain but might exceed the costs that have been suggested by recent policy assessments.     

Weekly greenhouse gas emissions of municipalities: Methods and comparisons

Local authorities need timely information on their greenhouse gas (GHG) emissions and their causes, comparison with other municipalities and tools for dissemination of information to the citizens. This paper presents a weekly GHG emission calculation system, CO₂-report, which provides such data for citizens and local decision-makers in a timely manner, in contrast to the official emissions statistics, which are available on an annual basis 1–2 years afterwards. In this paper, we present the methodology and three main outputs of CO₂-report: (1) weekly GHG emissions; (2) advance annual emissions; and (3) final annual emissions for 2009 with comparison of 64 municipalities in Finland. We explain the reasons for the large variability of annual emissions, from 5 to 13 t CO₂-eq/capita, discuss the accuracy of advance and final emission estimates at local level, and show the weekly variability of emissions for three example municipalities with different emission profiles.