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1.
Road transport is one of the sectors with highest energy consumptions in the planet, with large dependence of fossil fuels, and contribution for global greenhouse gas emissions. Although, Latin America is not a high-energy consumer, its share in global consumption is expected to grow, especially in the transportation sector. This make essential for developing countries the adoption of better policies to identify the vehicle groups with largest fuel demands. The present study describes the VKT technique to disaggregate road transport energy consumption by vehicle type, applied to the road transportation system of Ecuador. It also describes the procedures performed to estimate the variables required to run the model, and some of the practical applications that be used to create public policies. Results show as the biggest fuel consumers the heavy-duty freight cargo, followed by light duty vehicles. The estimation of greenhouse gas emissions evidence that road transport released 14.3 million tons of CO2 in 2012. When fuel consumption is compared by it costs, it can be confirmed that Ecuadorean Government covered, through subsidies, for 68% of the annual fuel costs of national road transport, demonstrating the importance of restructuring these expenditures in order to achieve an efficient road transport system.  相似文献   

2.
Sustainable supply of energy at affordable prices is vital to ensure the human development. ASEAN is committed pursuing for a clean and green region with fully established mechanisms for sustainable development to ensure the protection of regional environment, resources and the high quality of people's life. Nowadays, energy use in the transportation sector represents an important issue in ASEAN countries. Therefore, it is believed that the introduction of fuel economy standards and labels is the key to save energy in this sector. Fuel economy standards and labels are relatively cheap measure to influence consumer behaviour and to induce car manufacturers to produce more efficient vehicles. Fuel economy standards and labels for vehicle are being implemented in many countries around the world to save fuel consumption and mitigate CO2 emission. This paper is a review on fuel economy standard and labels for vehicle in some selected ASEAN countries such as Singapore, Indonesia, Malaysia, Philippines, Thailand and Vietnam. It has been found that Singapore is the leading country in ASEAN that has implemented fuel economy standards and labels. Moreover, it has been found that the implementation of cleaner fuels standard play a crucial role in protecting public health and the environment from transportation sector emissions. The most common alternative fuels used in ASEAN are biodiesel, ethanol, methanol, propane, hydrogen and natural gas.  相似文献   

3.
As the global demand for energy rapidly increases and fossil fuels will be soon exhausted, bio‐energy has become one of the key options for shorter and medium term substitution for fossil fuels and the mitigation of greenhouse gas emissions. Biomass currently supplies 14% of the world's energy needs. Biomass pyrolysis has a long history and substantial future potential—driven by increased interest in renewable energy. This article presents the state‐of‐the‐art of biomass pyrolysis systems, which have been—or are expected to be—commercialized. Performance levels, technological status, market penetration of new technologies and the costs of modern forms of biomass energy are discussed. Advanced methods have been developed in the last two decades for the direct thermal conversion of biomass to liquid fuels, charcoals and various chemicals in higher yields than those obtained by traditional pyrolysis processes. The most important reactor configurations are fluidized beds, rotating cones, vacuum and ablative pyrolysis reactors. Fluidized beds and rotating cones are easier for scaling and possibly more cost effective. Slow pyrolysis is being used for the production of charcoal, which can also be gasified to obtain hydrogen‐rich gas. The short residence time pyrolysis of biomass (flash pyrolysis), at moderate temperatures, is being used to obtain a high yield of liquid products (up to 70% wt), particularly interesting as energetic vectors. Bio‐oil can substitute for fuel oil—or diesel fuel—in many static applications including boilers, furnaces, engines and turbines for electricity generation. While commercial biocrudes can easily substitute for heavy fuel oils, it is necessary to improve the quality in order to consider biocrudes as a replacement for light fuel oils. For transportation fuels, high severity chemical/catalytic processes are needed. An attractive future transportation fuel can be hydrogen, produced by steam reforming of the whole oil, or its carbohydrate‐derived fraction. Pyrolysis gas—containing significant amount of carbon dioxide, along with methane—might be used as a fuel for industrial combustion. Presently, heat applications are most economically competitive, followed by combined heat and power applications; electric applications are generally not competitive. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

4.
Renewable power-to-fuel (PtF) is a key technology for the transition towards fossil-free energy systems. The production of carbon neutral synthetic fuels is primarily driven by the need to decouple the energy sector from fossil fuels dependance which are the main source of environmental issues. Hydrogen (H2) produced from water electrolysis powered by renewable electricity and direct carbon dioxide (CO2) captured from the flue gas generated by power plants, industry, transportation, and biogas production from anaerobic digestion, are used to convert electricity into carbon-neutral synthetic fuels. These fuels function as effective energy carriers that can be stored, transported, and used in other energy sectors (transport and industry). In addition, the PtF concept is an energy transformation that is capable of providing services for the balancing of the electricity grid thanks to its adaptable operation and long-term storage capacities for renewable energy surplus. As a consequence, it helps to potentially decarbonize the energy sector by reducing the carbon footprint and GHG emissions. This paper gives an overview on recent advances of renewable PtF technology for the e-production of three main hydrogen-based synthetic fuels that could substitute fossil fuels such as power-to-methane (PtCH4), power-to-methanol (PtCH3OH) and power-to-ammonia (PtNH3). The first objective is to thoroughly define in a clear manner the framework which includes the PtF technologies. Attention is given to green H2 production by water electrolysis, carbon capture & storage (CCS), CO2 hydrogenation, Sabatier, and Haber Bosch processes. The second objective is to gather and classify some existing projects which deal with this technology depending on the e-fuel produced (energy input, conversion process, efficiency, fuel produced, and application). Furthermore, the challenges and future prospects of achieving sustainable large-scale PtF applications are discussed.  相似文献   

5.
The two major energy challenges for the United States are replacing crude oil in our transportation system and eliminating greenhouse gas emissions. A domestic-source greenhouse-gas-neutral nuclear hydrogen biomass system to replace oil in the transportation sector is described. Some parts of the transportation system can be electrified with electricity supplied by nuclear energy sources that do not emit significant quantities of greenhouse gases. Other components of the transportation system require liquid fuels. Biomass can be converted to greenhouse-gas-neutral liquid fuels; however, the conversion of biomass-to-liquid fuels is energy intensive. There is insufficient biomass to meet U.S. liquid fuel demands and provide the energy required to process the biomass-to-liquid fuels. With the use of nuclear energy to provide heat, electricity, and hydrogen for the processing of biomass-to-liquid fuels, the liquid fuel production per unit of biomass is dramatically increased, and the available biomass could meet U.S. liquid fuel requirements.  相似文献   

6.
As the population and economy continue to grow globally, demand for energy will continue to grow. The transportation sector relies solely on petroleum for its energy supply. The United States and China are the top two oil-importing countries. A major issue both countries face and are addressing is energy insecurity as a result of the demand for liquid fuels. Improvements in the energy efficiency of vehicles and the substitution of petroleum fuels with alternative fuels can help contain growth in the demand for transportation oil. Although most alternative transportation fuels — when applied to advanced vehicle technologies — can substantially reduce greenhouse emissions, coal-based liquid fuels may increase greenhouse gas emissions by twice as much as gasoline. Such technologies as carbon capture and storage may need to be employed to manage the greenhouse gas emissions of coal-based fuels. At present, there is no ideal transportation fuel option to solve problems related to transportation energy and greenhouse gas emissions. To solve these problems, research and development efforts are needed for a variety of transportation fuel options and advanced vehicle technologies.  相似文献   

7.
This article surveys the liquid fuels picture for the year 2000 and concludes that transportation fuels will represent the critical domestic energy resource for the future. The United States must develop a synthetic fuels industry if it is to meet its transportation fuel needs while seeking to reduce its dependence on foreign crude oil. Synthetic fuels from coal and oil shale (methanol, gasoline, and diesel fuel) and methanol from biomass are depicted as the emerging options of the future. Within these options, methanol-from-coal is highlighted as providing the most technically versatile, economically viable, and environmentally sound choice. Based largely on transportation needs, the article presents a methanol market demand forecast calling for the consumption of 25 billion gal/y by the year 2000—enough to supply a fleet of 25 million methanol cars and provide for considerable methanol usage in the industrial, utility, and chemical sectors. Thus, about one out of every six cars in the automobile fleet would be operating on methanol if this forecast holds true. A survey of the cost estimates for producing alternative transportation fuels in the future shows, that methanol-from-coal could prove to be least expensive motor fuel: roughly two-thirds of the price of gasoline from crude oil and one-half the price of methanol from biomass. The article also poses some of the challenges facing the synfuels industry if it is going to overcome the entry barriers facing the establishment of a new fuel in the liquid fuels market place.  相似文献   

8.
The purpose of this study is to assess the political, economic and environmental impacts of producing hydrogen from biomass. Hydrogen is a promising renewable fuel for transportation and domestic applications. Hydrogen is a secondary form of energy that has to be manufactured like electricity. The promise of hydrogen as an energy carrier that can provide pollution-free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. Currently, most hydrogen is derived from non-renewable resources by steam reforming in which fossil fuels, primarily natural gas, but could in principle be generated from renewable resources such as biomass by gasification. Hydrogen production from fossil fuels is not renewable and produces at least the same amount of CO2 as the direct combustion of the fossil fuel. The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The major problem in utilization of hydrogen gas as a fuel is its unavailability in nature and the need for inexpensive production methods. Hydrogen production using steam reforming methane is the most economical method among the current commercial processes. These processes use non-renewable energy sources to produce hydrogen and are not sustainable. It is believed that in the future biomass can become an important sustainable source of hydrogen. Several studies have shown that the cost of producing hydrogen from biomass is strongly dependent on the cost of the feedstock. Biomass, in particular, could be a low-cost option for some countries. Therefore, a cost-effective energy-production process could be achieved in which agricultural wastes and various other biomasses are recycled to produce hydrogen economically. Policy interest in moving towards a hydrogen-based economy is rising, largely because converting hydrogen into useable energy can be more efficient than fossil fuels and has the virtue of only producing water as the by-product of the process. Achieving large-scale changes to develop a sustained hydrogen economy requires a large amount of planning and cooperation at national and international alike levels.  相似文献   

9.
《Journal of power sources》2006,156(2):497-511
With ever growing concerns on environmental pollution, energy security, and future oil supplies, the global community is seeking non-petroleum based alternative fuels, along with more advanced energy technologies (e.g., fuel cells) to increase the efficiency of energy use. The most promising alternative fuel will be the fuel that has the greatest impact on society. The major impact areas include well-to-wheel greenhouse gas emissions, non-petroleum feed stocks, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, and safety. Compared to some of the other leading alternative fuel candidates (i.e., methane, methanol, ethanol, and Fischer–Tropsch fuels), dimethyl ether appears to have the largest potential impact on society, and should be considered as the fuel of choice for eliminating the dependency on petroleum.DME can be used as a clean high-efficiency compression ignition fuel with reduced NOx, SOx, and particulate matter, it can be efficiently reformed to hydrogen at low temperatures, and does not have large issues with toxicity, production, infrastructure, and transportation as do various other fuels. The literature relevant to DME use is reviewed and summarized to demonstrate the viability of DME as an alternative fuel.  相似文献   

10.
To address the problem of fossil fuel usage at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and hydrogen use. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed Hydrogen production and End-Uses from CHHP system for the campus using local resources. Following the resource assessment study, the team selects FuelCell Energy DFC1500™ unit as a molten carbonate fuel cell to study of combined heat, hydrogen and power (CHHP) system based on a molten carbonate fuel cell fed by biogas produced by anaerobic digestion. The CHHP system provides approximately 650 kg/day. The total hydrogen usage 123 kg/day on the university campus including personal transportation applications, backup power applications, portable power applications, and other mobility applications are 56, 16, 29, 17, and 5 respectively. The excess hydrogen could be sold to a gas retailer. In conclusion, the CHHP system will be able to reduce fossil fuel usage, greenhouse gas emissions and hydrogen generated is used to power different applications on the university campus.  相似文献   

11.
Abstract

It has been suggested that renewable energy sources be considered as replacements or diluents for middle distillate ground transportation fuels. It is vital for the operational considerations of these fuels to investigate the many positives and negatives that this use could prompt. In proposing such a replacement, considerations must be given to the many problems that could arise. Problems to be studied include fuel storage stability, fuel solubility, and oxidative stability. Unlike newly manufactured soy oils, it was found that this recycled soy oil was not stable in fuels. The question was, what in the recycled oil led to the observed fuel degradation.  相似文献   

12.
As domestic petroleum supplies diminish and prices escalate, the U.S. Air Force will need to consider the implications of relying on primary energy resources other than petroleum for its aviation fuel needs. Our recent studies have examined various candidate synthetic fuels and the types of vehicles in which they might be employed. In this paper, we have emphasized those results which highlight the possible use of liquid hydrogen as a fuel for very large airplanes (with maximum gross weights in excess of one million pounds).

Comparisons are provided of the life-cycle costs and life-cycle energy consumption for both synthetic jet-fuel and liquid hydrogen fueled airplanes. Both fuels are assumed to be synthesized from coal. In addition, the relative cost-effectiveness and energy-effectiveness of the two alternatives are presented for a variety of mission applications.

These results suggest that a synthetic jet-fuel (similar to today's Jet-A or JP-4) derived from coal is more attractive than liquid hydrogen as a military aircraft fuel.  相似文献   


13.
In this study, two potential fuels, namely hydrogen and ammonia, are alternatively proposed to replace heavy fuel oils in the engines of sea transportation vehicles. A comparative life cycle assessments of different types of sea transportation vehicles are performed to investigate the impacts of fuel switching on the environment. The entire transport life cycle is considered in the life cycle analyses consisting of production of freight ship and tanker; operation of freight ship and tanker; construction and land use of port; operation, maintenance and disposal of port; production and transportation of these clean fuels. Various environmental impact categories, such as global warming, marine sediment ecotoxicity, marine aquatic ecotoxicity, acidification and ozone layer depletion are selected in order to examine the diverse effects of switching to clean fuels in maritime transportation. As a carbon-free fuel for marine vehicle engines, ammonia and hydrogen, yield considerably lower global warming impact during the operation. Furthermore, numerous production methods of alternative fuels are evaluated to comparatively show environmentally benign options. The results of this study demonstrate that if ammonia is even partially utilized in the engines of ocean tankers as dual fuel (with heavy fuel oils), overall life cycle greenhouse gas emissions per tonne-kilometer can be decreased about 27% whereas it can be decreased by about 40% when hydrogen is used as dual fuel.  相似文献   

14.
This paper discusses the potential energy security implications of a national low carbon fuel standard (NLCFS). A low carbon fuel standard is designed to reduce greenhouse gas (GHG) emissions by targeting the fuel portion of the fuel-vehicle system. Specifically, a NLCFS would set national targets for the average carbon intensity (CI) of motor fuels, and establish a market for credits that allows fuel producers and importers to respond in a variety of ways to the signal provided by the credit price. An important method for lowering the CI of transportation is to substitute lower-carbon alternative fuels such as advanced biofuels, electricity, CNG, and H2. Despite the focus on GHGs, so long as transportation fuels remain dominated by petroleum, transportation fuel policies like a NLCFS also will be evaluated in terms of their energy security impacts. We examine the fuel substitutions that are projected to be induced by a NLCFS and consider the energy security implications of displacing higher carbon fuels, such as imported Canadian Oil Sands oil or certain imported crude oils, with lower-carbon domestic oil, biofuels, or lower carbon oil imported from other sources.  相似文献   

15.
Fuel cells are under development for a range of applications for transport, stationary and portable power appliances. Fuel cell technology has advanced to the stage where commercial field trials for both transport and stationary applications are in progress. The electric efficiency typically varies between 40 and 60% for gaseous or liquid fuels. About 30–40% of the energy of the fuel is available as heat, the quality of which varies based on the operating temperature of the fuel cell. The utilisation of this heat component to further boost system efficiency is dictated by the application and end-use requirements. Fuel cells utilise either a gaseous or liquid fuel with most using hydrogen or synthetic gas produced by a variety of different means (reforming of natural gas or liquefied petroleum gas, reforming of liquid fuels such as diesel and kerosene, coal or biomass gasification, or hydrogen produced via water splitting/electrolysis). Direct Carbon Fuel Cells (DCFC) utilise solid carbon as the fuel and have historically attracted less investment than other types of gas or liquid fed fuel cells. However, volatility in gas and oil commodity prices and the increasing concern about the environmental impact of burning heavy fossil fuels for power generation has led to DCFCs gaining more attention within the global research community. A DCFC converts the chemical energy in solid carbon directly into electricity through its direct electrochemical oxidation. The fuel utilisation can be almost 100% as the fuel feed and product gases are distinct phases and thus can be easily separated. This is not the case with other fuel cell types for which the fuel utilisation within the cell is typically limited to below 85%. The theoretical efficiency is also high, around 100%. The combination of these two factors, lead to the projected electric efficiency of DCFC approaching 80% - approximately twice the efficiency of current generation coal fired power plants, thus leading to a 50% reduction in greenhouse gas emissions. The amount of CO2 for storage/sequestration is also halved. Moreover, the exit gas is an almost pure CO2 stream, requiring little or no gas separation before compression for sequestration. Therefore, the energy and cost penalties to capture the CO2 will also be significantly less than for other technologies. Furthermore, a variety of abundant fuels such as coal, coke, tar, biomass and organic waste can be used. Despite these advantages, the technology is at an early stage of development requiring solutions to many complex challenges related to materials degradation, fuel delivery, reaction kinetics, stack fabrication and system design, before it can be considered for commercialisation. This paper, following a brief introduction to other fuel cells, reviews in detail the current status of the direct carbon fuel cell technology, recent progress, technical challenges and discusses the future of the technology.  相似文献   

16.
ABSTRACT

For fetching day-to-day energy needs, current energy requirement majorly depends on fossil fuels. But ambiguous matter like abating petroleum products and expanding air pollution has enforced the experts to strive for another fuel which can be used as an alternative or reduce the applications of fossil fuels. Considering the issues, the main objective of the present study is to find the feasibility by using blends of rice bran oil biodiesel and diesel which are used as pilot fuels by blending 10% and 20% biodiesel in fossil diesel and biogas, introduced as gaseous fuel by varying its mass flow rate in a dual-fuel engine mode. An experimentation study was carried out to find the performance and emission parameters of the engine relative to pure diesel. The results were very much similar to the majority of researchers who used biodiesel and gaseous fuels in a dual-fuel engine. Brake specific fuel consumption (BSFC) of the engine was noticed to have increased, while brake thermal efficiency was on the lower side in dual fuel mode in comparison with regular diesel. In relation with conventional diesel, it was noticed that combined effect of rice bran methyl esters and varying mass flow rate of biogas showed a decrement in NO x and smoke emissions, whereas HC and CO exhalations were on higher side when biogas and biodiesel were utilized collectively in dual-fuel engine. Hence, it was concluded that combination of blends of biodiesel and diesel and introduction of biogas in the engine can be a promising combination which can be used as a substitute fuel for addressing future energy needs.  相似文献   

17.
One of the important goals in today's world is sustainable power generation by using low or zero polluting fuels and energy conversion devices. In this context, utilization of gaseous fuels in internal combustion (IC) engines is focused more due to their better fuel mixing ability with air, higher combustion efficiency, easier transportation, and lower pollutant formation. Liquefied petroleum gas (LPG), compressed natural gas (CNG), hydrogen, and biogas are considered as commonly available alternative gaseous fuels for IC engines. Yet, a search for other possible alternative gaseous fuels is continuing in the world. In recent years, Oxy-hydrogen (HHO) also known as Brown's gas has been explored by many researchers in the world, for the possibility of using it for heat and power applications. Because of this, a comprehensive review of the production of HHO using different generators and its utilization in heat and power applications has been carried out, and the discussions are presented in this paper.  相似文献   

18.
The Korean coal industry is in a transition under low carbon policy through the steady reduction of coal production. Since consumer subsidy for the consumption of anthracites briquette in low-income households caused a distortion in domestic coal market, the so-called coupon program will be the first target in energy reform policy in order to induce fuel switching from anthracites to alternative clean energy. This paper tries to identify various factors that influence households' fuel switching decision. Disutility from briquette consumption is also considered as an important factor. Using the 2007 census data on briquette-consuming households, it is found that the coupon program provides an adverse effect to switching fuels to clean energy while the disutility of briquettes is positively associated with the probability of fuel switching. However, the empirical finding suggests that the policy alone attempting to remove coupon program may fail to switch fuels unless the cost of boiler changes is substantially reduced through the provision of accessible networks to alternative energy sources. It indicates that reform policy for consumer subsidy must be understood in line with more comprehensive regional energy plans to resolve energy poverty issue.  相似文献   

19.
In this paper, the modern biomass-based transportation fuels such as fuels from Fischer–Tropsch synthesis, bioethanol, fatty acid (m)ethylester, biomethanol, and biohydrogen are briefly reviewed. Here, the term biofuel is referred to as liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. There are several reasons for bio-fuels to be considered as relevant technologies by both developing and industrialized countries. They include energy security reasons, environmental concerns, foreign exchange savings, and socioeconomic issues related to the rural sector. The term modern biomass is generally used to describe the traditional biomass use through the efficient and clean combustion technologies and sustained supply of biomass resources, environmentally sound and competitive fuels, heat and electricity using modern conversion technologies. Modern biomass can be used for the generation of electricity and heat. Bioethanol and biodiesel as well as diesel produced from biomass by Fischer–Tropsch synthesis are the most modern biomass-based transportation fuels. Bio-ethanol is a petrol additive/substitute. It is possible that wood, straw and even household wastes may be economically converted to bio-ethanol. Bio-ethanol is derived from alcoholic fermentation of sucrose or simple sugars, which are produced from biomass by hydrolysis process. Currently crops generating starch, sugar or oil are the basis for transport fuel production. There has been renewed interest in the use of vegetable oils for making biodiesel due to its less polluting and renewable nature as against the conventional petroleum diesel fuel. Biodiesel is a renewable replacement to petroleum-based diesel. Biomass energy conversion facilities are important for obtaining bio-oil. Pyrolysis is the most important process among the thermal conversion processes of biomass. Brief summaries of the basic concepts involved in the thermochemical conversions of biomass fuels are presented. The percentage share of biomass was 62.1% of the total renewable energy sources in 1995. The reduction of greenhouse gases pollution is the main advantage of utilizing biomass energy.  相似文献   

20.
中国燃料电池发电技术展望   总被引:1,自引:0,他引:1  
本文主要叙述了我国后续能源领域中燃料电池发电技术的发展利用现状和技术展望,特别在文中提出燃料电池发电技术的发展必须要与其它新能源、新材料技术的发展相结合,例如:利用太阳能、风能从空气中提取纯水,从纯水中电解制氢,海水淡化制取纯水技术,以用生物方法从植物废弃物中制取的乙醇作为燃料电池的燃料,这些技术在我国未来能源应用领域具有广泛的潜在市场。同时简单概括了燃料电池发电技术能够大规模应用需考虑的几个关键性问题和我国燃料电池发电商业化的可行性及应用前景。  相似文献   

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