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.     

Energy and associated greenhouse gas emissions from household appliances in Malaysia

Today, electricity is an indispensable key for civilization and development. The trend of electricity consumption is rather escalating. Electricity generation principally depends upon fossil fuels. In one hand, the stocks of these fuels have been confirmed to be critically limited. On the other hand, in process of electricity generation by means of these fuels, a number of poisonous by-products adversely affect the conservation of natural eco-system. Further, electricity driven appliances use emanate anti-environmental gases that also affect human health and climate. Therefore, estimation of energy consumption for operating household appliances, savings of energy under policy intervention, and emission of poisonous gases in a fast developing country deserve academic attention.     

Characterization of energy use and performance of global cheese processing

The global cheese-making industry processes approximately one quarter of total raw milk production to create a variety of consumer cheeses, and cheese processing can be very energy-intensive. Characterizing energy usage in existing cheese markets and plants can provide baseline information to allow comparisons of energy performance of individual plants and systems. In this paper, we analyzed energy data compiled through extensive literature reviews on cheese-making across various countries and regions. The study has found that the magnitudes of average final energy intensity exhibited significant variations, ranging from 4.9 to 8.9 MJ per kg cheese across a few countries. In addition, the final energy intensity of individual plants exhibited even more significant variations, ranging from 1.8 to 68.2 MJ per kg of cheese from the countries in this study. These significant differences have indicated large potential energy savings' opportunities in the sector. The paper also indicates that there are positive association between implementation of energy measures and the decreasing trends of specific energy consumption over time, and suggests that developing and promulgating an energy-benchmarking framework including a process step approach and efficiency measures should be recommended for evaluating energy performance and improving energy efficiency in cheese-making industry.     

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.     

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.     

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 during the production of a passenger car in China

Rapidly-rising oil demand and associated greenhouse gas (GHG) emissions from road vehicles in China, passenger cars in particular, have attracted worldwide attention. As most studies to date were focused on the vehicle operation stage, the present study attempts to evaluate the energy demand and GHG emissions during the vehicle production process, which usually consists of two major stages—material production and vehicle assembly. Energy demand and GHG emissions in the material production stage are estimated using the following data: the mass of the vehicle, the distribution of material used by mass, and energy demand and GHG emissions associated with the production of each material. Energy demand in the vehicle assembly stage is estimated as a linear function of the vehicle mass, while the associated GHG emission is estimated according to the primary energy sources. It is concluded that the primary energy demand, petroleum demand and GHG emissions during the production of a medium-sized passenger car in China are 69,108 MJ, 14,545 MJ and 6575 kg carbon dioxide equivalent (CO₂-eq). Primary energy demand, petroleum demand and GHG emissions in China’s passenger car fleets in 2005 would be increased by 22%, 5% and 30%, respectively, if the vehicle production stage were included.     

Utilizing hydrogen energy to reduce greenhouse gas emissions in Canada's residential sector

An analysis of the potential to reduce greenhouse gas emissions in the residential sector by using hydrogen energy is reported. The residential sectors in provinces across Canada are considered. Greenhouse gas emissions are determined from the consumption of fossil fuels associated with the energy requirements in the residential sector. The use of hydrogen technologies in the residential sector is compared to conventional systems. The results are determined to vary by province, with the greatest attainable annual reductions in greenhouse gas emissions observed for heating to be in Alberta (7.2 t CO₂) and for power generation to be in Saskatchewan (7.2 t CO₂). The results suggest that hydrogen technologies for heating and power generation are promising options for reducing greenhouse gas emissions in Canada and its provinces.     

Energy intensities and greenhouse gas emission mitigation in global agriculture

Energy efficiency and greenhouse gas emissions are closely linked. This paper reviews agricultural options to reduce energy intensities and their impacts, discusses important accounting issues related to system boundaries, land scarcity, and measurement units and compares agricultural energy intensities and improvement potentials on an international level. Agricultural development in recent decades, while increasing yields, has led to lower average energy efficiencies when comparing the 1960s and the mid 1980s. In the two decades thereafter, energy intensities in developed countries increased, but with little impact on greenhouse gas emissions. Efficiency differences across countries in the year 2000 suggest a maximum improvement potential of 500 million tons of CO₂ annually. If only below average countries would increase their energy efficiency to average levels of the year 2000, the resulting emission reductions would be below 200 million tons of CO₂ annually.

Energy savings certificates: A market-based tool for reducing greenhouse gas emissions

Energy savings certificates (ESCs) are potentially a major tool that can be used by regulators and policy makers in reducing greenhouse gas (GHG) emissions. In this paper, we present our findings on the experience to date with ESCs, outline potential program opportunities in the US, and conclude with our perspective on how to proceed with the use of ESCs, particularly as a component of GHG reduction programs.     

Oil and natural gas prices and greenhouse gas emission mitigation

The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO₂. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.     

Land clearing and greenhouse gas emissions from Jatropha biofuels on African Miombo Woodlands

The paper investigates greenhouse gas (GHG) emissions from land use change associated with the introduction of large-scale Jatropha curcas cultivation on Miombo Woodland, using data from extant forestry and ecology studies about this ecosystem. Its results support the notion that Jatropha can help sequester atmospheric carbon when grown on complete wastelands and in severely degraded conditions. Conversely, when introduced on tropical woodlands with substantial biomass and medium/high organic soil carbon content, Jatropha will induce significant emissions that offset any GHG savings from the rest of the biofuel production chain. A carbon debt of more than 30 years is projected. On semi-degraded Miombo the overall GHG balance of Jatropha is found to hinge a lot on the extent of carbon depletion of the soil, more than on the state of the biomass. This finding points to the urgent need for detailed measurements of soil carbon in a range of Miombo sub-regions and similar tropical dryland ecosystems in Asia and Latin America. Efforts should be made to clarify concepts such as ‘degraded lands’ and ‘wastelands’ and to refine land allocation criteria and official GHG calculation methodologies for biofuels on that basis.     

Valuing the greenhouse gas emissions from nuclear power: A critical survey

This article screens 103 lifecycle studies of greenhouse gas-equivalent emissions for nuclear power plants to identify a subset of the most current, original, and transparent studies.     

Mitigating greenhouse gas emissions from China's cities: Case study of Suzhou

Knowledge of the factors driving greenhouse gas (GHG) emissions from cities is crucial to mitigating China's anthropogenic emissions. In this paper, the main drivers increasing GHG emissions from the Chinese city of Suzhou between 2005 and 2010 were identified and quantitatively analyzed using the Kaya identity and the log-mean Divisia index method. We found that economy and population were the major drivers of GHG emissions in Suzhou, having contributed 162.20% and 109.04%, respectively, to the increase in emissions. A decline in carbon intensity, which was caused by the declining energy intensity and an adjustment to the mixture of power and industrial structures, was the major determinant and accounted for a reduction of 171.24% in GHG emissions. Slowing and maintaining healthy growth rates of economy and population could be the primary and most effective means if Suzhou tries to curb the total emissions over the short term. It may be more realistic for Suzhou to control emissions by optimizing the economic structure for low-carbon industrial development because of the city's relative high energy requirements and low potential to mitigate GHGs by adjusting the energy mixture.     

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.     

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.     

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.     

Planning regional energy system in association with greenhouse gas mitigation under uncertainty

Greenhouse gas (GHG) concentrations are expected to continue to rise due to the ever-increasing use of fossil fuels and ever-boosting demand for energy. This leads to inevitable conflict between satisfying increasing energy demand and reducing GHG emissions. In this study, an integrated fuzzy-stochastic optimization model (IFOM) is developed for planning energy systems in association with GHG mitigation. Multiple uncertainties presented as probability distributions, fuzzy-intervals and their combinations are allowed to be incorporated within the framework of IFOM. The developed method is then applied to a case study of long-term planning of a regional energy system, where integer programming (IP) technique is introduced into the IFOM to facilitate dynamic analysis for capacity-expansion planning of energy-production facilities within a multistage context to satisfy increasing energy demand. Solutions related fuzzy and probability information are obtained and can be used for generating decision alternatives. The results can not only provide optimal energy resource/service allocation and capacity-expansion plans, but also help decision-makers identify desired policies for GHG mitigation with a cost-effective manner.     

Full-energy-chain analysis of greenhouse gas emissions for solar thermal electric power generation systems

Renewable energy generation of electricity is advocated as a means of reducing carbon dioxide emissions associated with the generation from fossil fuels. Whilst it is true that renewable sources do not generate significant carbon dioxide whilst producing electricity, as with fossil-fuelled plants they do embody significant emissions in their materials of construction. The “full-chain” environmental impacts of wind, hydro, solar-thermal and photovoltaic conversion are quite different and the likely trend in future reduction of embodied energy of next generation systems reflects the relative maturity of each technology. There has been much recent development of solar thermal electricity generation options for which there is a wide divergence in embodied CO₂ emissions.     

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.