Taxation on vehicle fuels: its impacts on switching to cleaner fuels

Vehicular consumption of fossil fuel contributes over 90% of air pollution in Hong Kong. A key strategy to improve Hong Kong's air quality is to discourage dirty fuels (e.g., leaded petrol and high-sulphur diesel) and to promote the use of clean fuels (e.g., low-sulphur diesel and liquefied petroleum gas (LPG)). This paper presents the empirical evidence on the effectiveness of the Government's clean fuel programs that offer tax subsidy to lower the consumption cost of such fuels. For the cases of unleaded petrol and ultra-low-sulphur diesel, lower fuel duties were offered so that the prices of these fuels were below those of leaded petrol and conventional diesel. Conventional petrol and diesel were phased out. In order to decide on the level of fuel duty concessions required to introduce LPG for taxis and bio-diesel for other vehicles, various Government-run trial programs were introduced to obtain cost estimates of using these alternative cleaner fuels. LPG using vehicles were subsequently exempted from the fuel duty in order to attract taxi and light bus operators to switch to LPG. It is apparent that the higher the subsidy, the faster is the rate at which switching to cleaner fuels takes place.     

Mechanism reduction for multicomponent surrogates: A case study using toluene reference fuels

Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid over comprehensive and high-temperature ranges of conditions were developed at varying levels of detail. These skeletal mechanisms were generated based on autoignition simulations, and validation using ignition delay predictions showed good agreement with the detailed mechanism in the target range of conditions. When validated using phenomena other than autoignition, such as perfectly stirred reactor and laminar flame propagation, tight error control or more restrictions on the reduction during the sensitivity analysis stage were needed to ensure good agreement. In addition, tight error limits were needed for close prediction of ignition delay when varying the mixture composition away from that used for the reduction. In homogeneous compression-ignition engine simulations, the skeletal mechanisms closely matched the point of ignition and accurately predicted species profiles for lean to stoichiometric conditions. Furthermore, the efficacy of generating a multicomponent skeletal mechanism was compared to combining skeletal mechanisms produced separately for neat fuel components; using the same error limits, the latter resulted in a larger skeletal mechanism size that also lacked important cross reactions between fuel components. Based on the present results, general guidelines for reducing detailed mechanisms for multicomponent fuels are discussed.     

Household energy consumption pattern and socio-cultural dimensions associated with it: A case study of rural Haryana, India

A survey of household energy consumption pattern was carried out in a village of Jhajjhar district of Haryana, India in the year 2007. The households surveyed covered heterogeneous population belonging to different income, educational and social groups. There was more availability and utilization of solid biomass fuels as energy resources in domestic sector as compared to the commercial fuels. Dung cakes, crop residues and firewood were found to be the three main fuels used for cooking, though LPG was also used along with biomass fuels. But complete conversion to cleaner fuels has not taken place yet even in households that has been using LPG for many years. Income was an important factor determining the choice of fuel for cooking, but there were some socio-cultural factors which were equally important in making fuel preferences at household level.     

Environmental life cycle assessment of alternative fuels for city buses: A case study in Oujda city,Morocco

The road transport sector, particularly public transport, generates significant greenhouse gas emissions due to the excessive use of petroleum-based fuels. The use of alternative fuels with lower environmental impacts is therefore a major challenge to move towards a more sustainable public transport sector. In this context, the current study presents an environmental life cycle assessment of alternative buses, including hybrid (diesel-electricity), electric, and fuel cell buses at a city level in Oujda, Morocco. This study is perfromed according to three main outputs: total energy use by fuel type, GHG emissions, and criteria air pollutants. It is concluded that electric and fuel cell buses represent efficient and sustainable alternatives to public transport during the operational phase and their deployment in Oujda city can potentially offer significant environmental savings in terms of GHG emissions and air pollutants during both the WTT and TTW phases.     

Co-production of synthetic fuels and district heat from biomass residues,carbon dioxide and electricity: Performance and cost analysis

Large-scale systems suitable for the production of synthetic natural gas (SNG), methanol or gasoline (MTG) are examined using a self-consistent design, simulation and cost analysis framework. Three basic production routes are considered: (1) production from biomass via gasification; (2) from carbon dioxide and electricity via water electrolysis; (3) from biomass and electricity via hybrid process combining elements from routes (1) and (2). Process designs are developed based on technologies that are either commercially available or successfully demonstrated at precommercial scale. The prospective economics of future facilities coproducing fuels and district heat are evaluated from the perspective of a synthetic fuel producer. The levelised production costs range from 18–37 €/GJ for natural gas, 21–40 €/GJ for methanol and 23–48 €/GJ for gasoline, depending on the production route. For a given end-product, the lowest costs are associated with thermochemical plant configurations, followed by hybrid and electrochemical plants.     

Waste to liquid fuels: potency,progress and challenges

The valorization of municipal solid waste (MSW) into liquid fuels is a multi‐beneficial global option for ensuring environmental and energy sustainability. The paper critically reviewed a wide range of recent literature on the potency, progress, and challenges associated with MSW upgrading into liquid fuels. Concise details on the various upgrading technologies involved such as gasification, pyrolysis, and syngas‐to‐fuels (i.e., syngas to gasoline and diesel) via a Fischer–Tropsch process were documented. Emphasis was critically given to the recent literature updates. The paper explored the role of heterogeneous catalyst systems in achieving the various processes with special considerations for optimizing fuel yield. Prospective technologies such as plasma gasification and nanoscale catalyst design with potentials to revolutionize the industry were also discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Environmental aspects of ethanol-based fuels from Brassica carinata: A case study of second generation ethanol

One of the main challenges faced by mankind in the 21st century is to meet the increasing demand for energy requirements by means of a more sustainable energy supply. In countries that are net fossil fuel importers, expectation about the benefit of using alternative fuels on reducing oil imports is the primary driving force behind efforts to promote its production and use. Spain is scarce in domestic energy sources and more than 50% of the energy used is fossil fuel based. The promotion of renewable energies use is one of the principal vectors in the Spanish energy policy. Selected herbaceous crops such as Brassica carinata are currently under study as potential energy sources. Its biomass can be considered as potential feedstock to ethanol conversion by an enzymatic process due to the characteristics of its composition, rich in cellulose and hemicellulose. This paper aims to analyse the environmental performance of two ethanol-based fuel applications (E10 and E85) in a passenger car (E10 fuel: a mixture of 10% ethanol and 90% gasoline by volume; E85 fuel: a mixture of 85% ethanol and 15% gasoline by volume) as well as their comparison with conventional gasoline as transport fuel. Two types of functional units are applied in this study: ethanol production oriented and travelling distance oriented functional units in order to reflect the availability or not of ethanol supply. E85 seems to be the best alternative when ethanol production based functional unit is considered in terms of greenhouse gas (GHG) emissions and E10 in terms of non-renewable energy resources use. Nevertheless, E85 offers the best environmental performance when travelling distance oriented functional unit is assumed in both impacts. In both functional unit perspectives, the use of ethanol-based fuels reduces the global warming and fossil fuels consumption. However, the contributions to other impact indicators (e.g. acidification, eutrophication and photochemical oxidants formation) were lower for conventional gasoline.Life Cycle Assessment (LCA) procedure helps to identify the key areas in the B. carinata ethanol production life cycle where the researchers and technicians need to work to improve the environmental performance. Technological development could help in lowering both the environmental impact and the prices of the ethanol fuels.     

Life cycle impacts of waste wood biomass heating systems: A case study of three UK based systems

With increasing renewable energy targets and the use of biomass for energy production, questions arise about the sustainability of differing types of bioenergy. Much has been made about the renewable transport fuel obligations and the impact the production of biofuel can have on the environment, but there has been less consideration of more small scale biomass heating systems. This work examines the life cycle impacts of the production and use of three such systems using waste wood in the South West of England. Burning of wood in the UK was reduced after the introduction of legislation to reduce smog in the 1950s, and so the impact of the emissions from the boilers has been examined. Whilst the boilers studied complied with UK emissions legislation, the emissions were the most significant impact found. However, there were differences in the emission levels depending on the loading of the boiler. In all cases the energy payback of the systems was under one year, ranging from approximately four to ten months.     

Influences of hydrogen and various gas fuel addition to different liquid fuels on the performance characteristics of a spark ignition engine

This study reports the impacts of dual fuel mixtures on the theoretical performance characteristics of a spark ignition engine (SIE). The effects of addition of liquefied hydrogen, methane, butane, propane (additive fuels) into gasoline, iso-octane, benzene, toluene, hexane, ethanol and methanol fuels (primary fuels) on the variation of power, indicated mean effective pressure (IMEP), thermal efficiency, exergy efficiency, were examined by using a combustion model. The fuel additives were ranged from 10 to 50% by mass. The results exhibited that the ratios of hydrogen, methane, butane, propane noticeably affect the performance of the engine. The maximum increase ratio of power is 82.59% with 50% of toluene ratio and its maximum decrease ratio is 10.84% with 50% of methanol ratio in hydrogen mixtures. The maximum increase ratio of thermal efficiency and exergy efficiency are observed as 26.75% and 32.23% with the combustion of benzene-hydrogen mixtures. The maximum decrease ratio of thermal efficiency is 29.71% with the combustion of 50% of methanol ratio and it is 21.95% for the exergy efficieny with the combustion of 50% of ethanol ratio in hydrogen mixtures. The power, IMEP, thermal efficiency and exergy efficiency of primary fuels demonstrate different variation characteristics with respect to type and ratio of additive fuels.     

Spray properties of alternative fuels: A comparative analysis of biodiesel and diesel

Physical properties of biodiesel play an important role in the injection, atomization and combustion performance. An experiment was carried out to investigate the spray properties of biodiesel. The experimental setup was based on an electronic unit‐pump (EUP) bench, a constant volume chamber and a high‐speed digital camera. The photographs of spray were dealt with by using an image processing procedure. Then the spray tip penetrations and cone angles were obtained and analyzed. The experimental results indicate that the spray tip penetrations and cone angles of biodiesel increase with increasing injection duration. In addition, with decreasing ambient pressure the spray tip penetrations increase while the cone angles decrease. Furthermore, ambient pressure has a stronger effect on the spray properties of biodiesel than injection pressure. On the macroscopically view, the shape of biodiesel spray is similar to that of diesel. The final tip penetrations and cone angles of biodiesel are greater than those of diesel due to its higher viscosity, density and bulk modulus. Copyright © 2008 John Wiley & Sons, Ltd.     

Time-dependent opportunities in energy business: A comparative study of locally available renewable and conventional fuels

This work investigates and compares energy-related, private business strategies, potentially interesting for investors willing to exploit either local biomass sources or strategic conventional fuels. Two distinct fuels and related power-production technologies are compared as a case study, in terms of economic efficiency: the biomass of cotton stalks and the natural gas. The carbon capture and storage option are also investigated for power plants based on both fuel types. The model used in this study investigates important economic aspects using a “real options” method instead of traditional Discounted Cash Flow techniques, as it might handle in a more effective way the problems arising from the stochastic nature of significant cash flow contributors’ evolution like electricity, fuel and CO₂ allowance prices. The capital costs have also a functional relationship with time, thus providing an additional reason for implementing “real options” as well as the learning-curves technique. The methodology as well as the results presented in this work, may lead to interesting conclusions and affect potential private investment strategies and future decision making. This study indicates that both technologies lead to positive investment yields, with the natural gas being more profitable for the case study examined, while the carbon capture and storage does not seem to be cost efficient with the current CO₂ allowance prices. Furthermore, low interest rates might encourage potential investors to wait before actualising their business plans while higher interest rates favor immediate investment decisions.     

Assessment of the fuel wood of India: A case study based on fuel characteristics of some indigenous species of Arunachal Pradesh

Biomass in the form of fuelwood has been a source of energy for many centuries all over the world. In rural India, fuelwood remains the first choice of energy source. Arunachal Pradesh is home to many different tree species; so far most of the fuelwoods of Arunachal Pradesh have never been studied for their fuel characteristics. This study is carried out with the following objectives: (i) Identification and selection of indigenous fuelwood species, which are widely distributed throughout Arunachal Pradesh, North East India; (ii) quantitative and qualitative analysis of these fuelwoods; and (iii) to rank these fuelwoods according to their fuel value index.     

A computational study on the combustion of hydrogen/methane blended fuels for a micro gas turbines

To understand the combustion performance of using hydrogen/methane blended fuels for a micro gas turbine that was originally designed as a natural gas fueled engine, the combustion characteristics of a can combustor has been modeled and the effects of hydrogen addition were investigated. The simulations were performed with three-dimensional compressible k-ε turbulent flow model and presumed probability density function for chemical reaction. The combustion and emission characteristics with a variable volumetric fraction of hydrogen from 0% to 90% were studied. As hydrogen is substituted for methane at a fixed fuel injection velocity, the flame temperatures become higher, but lower fuel flow rate and heat input at higher hydrogen substitution percentages cause a power shortage. To apply the blended fuels at a constant fuel flow rate, the flame temperatures are increased with increasing hydrogen percentages. This will benefit the performance of gas turbine, but the cooling and the NO_x emissions are the primary concerns. While fixing a certain heat input to the engine with blended fuels, wider but shorter flames at higher hydrogen percentages are found, but the substantial increase of CO emission indicates a decrease in combustion efficiency. Further modifications including fuel injection and cooling strategies are needed for the micro gas turbine engine with hydrogen/methane blended fuel as an alternative.     

The rebound effect,gender and social justice: A case study in Germany

Energy efficiency increases are essential in reducing energy consumption and CO₂ emissions. Policy is therefore rightly concerned about rebound effects, which cause energy and CO₂ emission reductions to be less than anticipated. A policy dilemma is emerging in that less economically privileged groups tend to show the highest rebound effects. Some studies suggest policymakers may therefore be reluctant to support energy efficiency upgrades among such groups. This paper argues this is based on a misunderstanding of the conceptual structure of the rebound effect. Firstly, a mathematical analysis confirms that the rebound effect is merely a comparison of proportions, not a measure of absolute levels of energy consumption, which are the real cause of increased CO₂ emissions. Secondly, an empirical study of commute distances in North-Rhine-Westphalia, Germany’s largest state, reveals that female commuters show considerably higher rebound effects than male commuters, both in time and cross-sectional analyses. However, male commuters consume the most energy and produce the most CO₂ emissions, by every measure. This resonates with recent studies showing the same disjunction between rebound effects and absolute consumption, in home heating among poorer and wealthier households. Policy needs to focus on absolute consumption levels and be cautious in interpreting rebound effects.     

An overview of the methanol reforming process: Comparison of fuels,catalysts, reformers,and systems

One of the main challenges facing power generation by fuel cells involves the difficulties related to hydrogen storage. Several methods have been suggested and studied by researchers to overcome this problem. Among these methods, using fuel reformers as a component of the fuel cell system is a practical and promising alternative to hydrogen storage. Among many hydrogen carrier fuels used in reformers, methanol is one of the most attractive ones because of its distinctive properties. To design and improve of the methanol reformate gas fuel cell systems, different aspects such as promising market applications for reformate gas–fueled fuel cell systems, and catalysts for methanol reforming should be considered. Therefore, our goal in this paper is to provide a comprehensive overview on the past and recent studies regarding methanol reforming technologies, while considering different aspects of this topic. Firstly, different fuel reforming processes are briefly explained in the first section of the paper. Then properties of various fuels and reforming of these fuels are compared, and the characteristics of commercial reformate gas–fueled systems are presented. The main objective of the first section of the paper is to give information about studies and market applications related to reformation of various fuels to understand advantages and disadvantages of using various fuels for different practical applications. In the next sections of the paper, advancements in the methanol reforming technology are explained. The methanol reforming catalysts and reaction kinetics studies by various researchers are reviewed, and the advantages and disadvantages of each catalyst are discussed, followed by presenting the studies accomplished on different types of reformers. The effects of operating parameters on methanol reforming are also discussed. In the last section of this paper, methanol reformate gas–fueled fuel cell systems are reviewed. Overall, this review paper provides insight to researchers on what has been accomplished so far in the field of methanol reforming for fuel cell power generation applications to better plan the next stage of studies in this field.     

Resource analysis of the Chinese society 1980–2002 based on exergy—Part 1: Fossil fuels and energy minerals

The resource inflow to the Chinese society from 1980 to 2002 is investigated based on exergy as a unified quantifier of natural resources. The major resources entering the society are divided into 17 sectors, with the annual policy for the individual group is analyzed corresponding to the exergy resource inflow. This study is divided into five consequential parts. This paper as the first part introduces the fossil fuels and energy materials entering the society, including coal, crude oil, natural gas, iron ores, nonferrous metal ores and nuclear power. The coal production, which comes form unified central planning, collective and individual parts, is analyzed according to the administrative institutions associated with variable policies. The consumption of coal is also described concerning thermal power generation, coking, heating, private consumption and gasification. The storage capacity, investment and import in crude oil production, which is imperative for the rapid economic development, are depicted. The natural gas production, slowly expanding during the study period, is illustrated according to the discovered and operating gas fields. Production of iron ores and nonferrous metal ores and nuclear power produced from uranium ores are represented in this paper.     

Economic and environmental evaluation of transporting imported pellet: A case study

This work compares the different methods of transport used to import pellets, through a case study of pellets imported into Italy. The objective was to evaluate the economic and environmental sustainability of the different transport methods, the former via a cost analysis, and the latter via an LCA analysis. In particular, the method of transport by sea from Virginia (USA) was compared to overland transport from some European locations. Industrial pellet markets strictly depend on the import of wood pellets from outside the EU-27. The analysis of transport phase is therefore crucial, for inspecting the consequences of transporting such a commodity along considerable distances and allowing decision makers to make strategic decisions about trade planning, optimize international routes, and choose the most sustainable transport methods. The economic analysis showed that road transport cost ranged from 18 to 112 € t⁻¹, while sea cost from 68 to 82 € t⁻¹. Concerning the environmental evaluation, the impact categories most involved were Fossil Fuels, Respiratory Inorganics and Land Use, showing that the critical points in the transport phase are the oil consumption per km and the production of high quantities of SO₂ and NO_x. Basically, transport by sea appeared to be better, from the economic viewpoint, and for what concerns one of the major environmental impacts involved (fossil fuels) and primary energy consumption, compared to road transport from some of the European locations normally supplying the Italian market. On the contrary, road transport was preferred if transporting pellets from locations nearest to Italy.     

Regional economic impacts of biomass based energy service use: A comparison across crops and technologies for East Styria,Austria

Biomass action plans in many European countries seek to expand biomass heat and fuel supply, mainly to be supplied by peripheral, agricultural regions. We develop a two-plus-ten-region energy-focused computable general equilibrium (CGE) model that acknowledges land competition in analysing the sub-state local-regional economic implications of such a strategy, embedded within a global context. Our model is based on a full cost analysis of selected biomass technologies covering a range of agricultural and forestry crops, as well as thermal insulation. The local-regional macroeconomic effects differ significantly across technologies and are governed by factors such as net labour intensity in crop production. The high land intensity of agricultural biomass products crowds out conventional agriculture, and thus lowers employment and drives up land prices and the consumer price index. The regional economic results show that net employment effects are positive for all forestry based biomass energy, and also show for which agriculture based biomass systems this is true, even when accounting for land competition. When regional consumer price development governs regional wages or when the agricultural sector is in strong enough competition to the international market, positive employment and welfare impacts vanish fully for agriculture based bio-energy.     

Modelling the promotion of biomass use: A case study of Thailand

This study develops a computable general equilibrium model of the Thailand economy which features several energy-specific enhancements. The model is used to simulate a number of potential policies to achieve the Thai government’s biomass-generated electricity targets contained in its 15-year renewable energy development plan. Examples of simulations conducted with the model include increasing biomass-based electricity purchased from small and very small power producers and increasing other agricultural residue use in electricity generation. The results indicate that implementation of all of the biomass-based electricity promotion policies is likely to achieve the short-run target and reduce somewhat the importation of fuels. However, the policy causes a huge increase in prices of biomass. The sugarcane-based sectors are big winners, while the cassava-based sectors are big losers. The losses can, however, be partly mitigated by promoting other agricultural residue use in electricity generation.     

Impact of reform and privatization on consumers: A case study of power sector reform in Orissa,India

Orissa is the first state in India to have undergone reform in the power sector, with the government withdrawing its control. The model of this reform is known as the WB–Orissa model. The goal of this paper is to examine the impact of this reform on consumers of electricity, which has been measured using multiple regression models. The variables represent the parameters that consumers are most interested in, and the regression coefficients represent the weights of the corresponding variables. The data were collected using a survey methodology. The impact of reform was found to be mixed. Some groups of consumers saw benefits, while others felt a negative impact. A focus group study was conducted to identify the variables of interest to consumers of electricity. The model was used to estimate consumer benefit and was validated using primary data and structural equation modeling. The study revealed beneficial aspects of reform and areas with no benefits.