Issues in land use planning for synthetic fuels from coal and biomass resources in the Midwestern U.S.A.

Proposed production of synthetic fuels from coal and biomass resources in the Midwestern U.S.A. raises important land use policy issues. These include agricultural lands protection; types of biomass development; equity for local communities; and government's role in land use and energy policy. Institutions that can address the central issues are lacking, and methods of planning for the land use impacts of energy development need to be improved.     

我国生物质能源现代化应用前景展望(二)——生物质制备液体燃料的转化途径

利用可再生生物质资源转化制备液体燃料已成为全球关注的热点。常见的生物质能源原料主要有草本植物、木本植物、微藻和脂肪类生物质资源,丰富的生物质资源为生物质液体燃料的生产提供了广泛的原料来源,也为生物质能源的多样性发展提供了坚实的物质基础。不同的生物质原料种类和转化方式可生产出性能各异的多种液体燃料,主要包括醇类燃料(乙醇、丁醇等)、烃类燃料和生物柴油等,由此构建出生物质转化制备液体燃料的转化途径网络。醇类燃料的生物质转化途径主要包括生物质直接发酵、生物质合成气发酵、生物质合成气化学合成等;烃类燃料的生物质转化途径主要有生物质液化加氢、微藻热化学途径、生物质合成气费托合成、生物质发酵脂肪酸加氢及油脂类加氢途径等;生物柴油的转化途径主要有油脂酯交换和微藻萃取酯交换。在这些液体燃料的转化途径中,只有生物质发酵制乙醇途径和油脂酯交换途径基本实现了商业化应用,其他大部分转化途径仍处于开发阶段。     

Energy security issues at household level in India

Energy security at the household level implies ensuring assured and regular supply of clean energy fuels at an affordable price for various household activities. Threat to physical availability of clean energy fuels for cooking and lighting is determined through various indicators such as dependence on traditional fuels and limited access to clean fuels. Energy insecurity translates into various adverse social impacts. Financial threat to energy security is indicated by expenses incurred on energy fuels and affordability of clean fuels. Households spend a major portion of their income on acquiring energy fuels; however, due to high price of clean fuels, they continue to depend on traditional and inefficient fuels. There is an urgent need to address factors that pose a threat to energy security at the household level. In this regard, measures taken by the government agencies and other institutions are also reviewed. The paper also suggests the regulatory and policy interventions required to address the energy security issues at the household level.     

Trends and sustainability criteria of the production and use of liquid biofuels

Environmental impacts associated with the use of fossil fuels, rising prices, potential limitations in supply and concerns about regional and national security are driving the development and use of biomass for bioenergy, biofuels and bioproducts. However, the use of biomass does not automatically imply that its production, conversion and use are sustainable. Conflicts between various ecosystem services (economic production of food, fodder and fuels, biodiversity, social and cultural values, etc.) that are provided by fertile land are increasing as well. Hence, a developed thinking on how to balance between these services is desirable.There is a significant amount of information available on biofuels and their sustainability. In this paper, different initiatives and sustainability criteria for biofuels are presented and assessed.35 criteria were found in emerging sustainability assessment frameworks. The majority of 12 criteria were focused on environmental issues, 4 were social and only 1 was economic. Energy balance and greenhouse gas balance were perceived as especially critical, social criteria ranked generally low. Although being perceived as important, food security ranked very low.     

Hydrogen versus synthetic fossil fuels

The fuels most considered for the post petroleum and natural gas era, hydrogen (gaseous and liquid) and synthetic fluid fossil fuels, have been compared by taking into account production costs, utilization efficiencies and environmental effects. Three different cost bases have been used for hydrogen depending on the primary energy sources used in its production. The results show that hydrogen is a much more cost effective energy carrier than synthetic fossil fuels. In addition to its environmental and efficiency benefits, hydrogen causes resource conservation, savings in transportation and capital investment, and reduction in inflation.     

Natural gas in Brazil's energy matrix: demand for 1995–2010 and usage factors

This paper describes and analyzes the constraints hampering achievement of the 12% share planned for natural gas in Brazil's energy matrix by 2010, and advises policies for reaching that goal on the basis of forecasts and three probable scenarios for the development of the Brazilian economy. The 12% share goal was established in 1993 by the Ministry of Mines and Energy and confirmed in 2000, and is now in full development. The figures used to represent the estimates of natural gas demands in the three scenarios were obtained from the Integrated Energy Planning Model (MIPE—Modelo Integrado de Planejamento Energético), which is a technical and economic forecasting model developed by a group of researchers linked to the Energy Planning Program run by the Graduate Engineering Programs Coordination Unit at the Rio de Janeiro Federal University (COPPE-UFRJ) under the sponsorship of Petrobras (a Brazilian enterprise operating in the oil and gas segment) and Eletrobrás (a Brazilian enterprise in charge of electricity demand planning). The analysis of the constraints take place under the aegis of the objective proposed by the Brazilian Government. The authors suggest specific actions to be taken in four application areas of natural gas: industrial, electric power generation, domestic distribution and vehicular fleet conversions. All the actions proposed encourage the use of a fuel with low environmental impacts and high calorie power, replacing firewood and other polluting fuels and are evaluated relative to the impacts occurring in society, especially from the standpoint of social welfare in a developing country. The necessity of developing the goods and services infrastructure in the country to support the natural gas insertion in the Brazilian energy matrix is also addressed.     

Evaluation of negative environmental impacts of electricity generation: Neoclassical and institutional approaches

Neoclassical and institutional economics have developed different theories and methodologies for evaluating environmental and social impacts of electricity generation. The neoclassical approach valuates external costs, and the institutional approach uses social cost valuation and MCDM methods. This paper focuses on three dimensions: theoretical and methodological backgrounds; critical review of specific studies: methodologies, results, and limitations; and discussing their results and implications for environmental policy and further research. The two approaches lead to a common conclusion that fossil fuels and nuclear power show the highest environmental impact. Despite the common conclusion, the conclusion has limited implications for environmental policy because of the weakness of their methodologies.     

Sustainability constraints on UK bioenergy development

Use of bioenergy as a renewable resource is increasing in many parts of the world and can generate significant environmental, economic and social benefits if managed with due regard to sustainability constraints. This work reviews the environmental, social and economic constraints on key feedstocks for UK heat, power and transport fuel. Key sustainability constraints include greenhouse gas savings achieved for different fuels, land availability, air quality impacts and facility siting. Applying those constraints, we estimate that existing technologies would facilitate a sustainability constrained level of medium-term bioenergy/biofuel supply to the UK of 4.9% of total energy demand, broken down into 4.3% of heat demands, 4.3% of electricity, and 5.8% of transport fuel. This suggests that attempts to increase the supply above these levels could have counterproductive sustainability impacts in the absence of compensating technology developments or identification of additional resources. The barriers that currently prevent this level of supply being achieved have been analysed and classified. This suggests that the biggest policy impacts would be in stimulating the market for heat demand in rural areas, supporting feedstock prices in a manner that incentivised efficient use/maximum greenhouse gas savings and targeting investment capital that improves yield and reduces land-take.     

Air pollution implications of increasing residential firewood use

The authors estimated air quality impacts due to residential firewood use for the year 2000 for 16 U.S. metropolitan areas. The wood usage estimates were based on price elasticities in relation to other space heating fuels, a range of future firewood prices, and an algorithm for the spatial distribution of wood use based on heating degree days and population density. This algorithm had been derived from county level data for New England from 1977 to 1978. The air quality impacts showed substantial increases in benzo(alpha)pyrene, an index of carcinogenic compounds, but did not suggest contravention of ambient air quality standards, in general.     

Subsidy strategies for energy technologies

The principal types of direct consumer subsidies to encourage the commercialization of unconventional energy sources (solar, conservation, synthetic fuels) are investigated. Although such subsidies can be justified on grounds that the prices to consumers of conventional energy alternatives do not reflect their full social costs, they all have serious drawbacks. Basically those subsidy schemes that are easy to administer encourage inefficient consumer behaviour while subsidies schemes that are efficient raise intractable problems of measurement. Subsidies for unconventional energy provide energy below its full social cost, thus giving the wrong price signals to the consumer. It would be more rational and effective to tax conventional energy up to its full social cost.     

Time-dependent climate benefits of using forest residues to substitute fossil fuels

In this study we analyze and compare the climate impacts from the recovery, transport and combustion of forest residues (harvest slash and stumps), versus the climate impacts that would have occurred if the residues were left in the forest and fossil fuels used instead. We use cumulative radiative forcing (CRF) as an indicator of climate impacts, and we explicitly consider the temporal dynamics of atmospheric carbon dioxide and biomass decomposition. Over a 240-year period, we find that CRF is significantly reduced when forest residues are used instead of fossil fuels. The type of fossil fuel replaced is important, with coal replacement giving the greatest CRF reduction. Replacing oil and fossil gas also gives long-term CRF reduction, although CRF is positive during the first 10-25 years when these fuels are replaced. Biomass productivity is also important, with more productive forests giving greater CRF reduction per hectare. The decay rate for biomass left in the forest is found to be less significant. Fossil energy inputs for biomass recovery and transport have very little impact on CRF.     

高热安定性喷气燃料JP900制备及性能

我国矿物燃料资源煤多油少,随着经济的发展和打赢高技术战争的需要,对油料的需求量越来越大,特别是航空油料的需求量,所以在今后相当长时期内,发展以煤代油技术是能源路线的重要方面,煤基合成燃料的研究开发亦受到充分重视。从此角度出发,介绍了一种高热安定性喷气燃料JP900,总结了该燃料的制备方法及其工艺流程,并对生产的关键技术进行了探讨,对产品性能进行了分析和对比。     

Long-term energy services security: What is it and how can it be measured and valued?

The paper reviews some recent approaches towards measuring the extent of long-term energy security and security externality valuation. It starts out to discuss the contextual connotations of notions of ‘energy security’ in medium to long-term time frames and reviews some indicators that have been proposed to quantify it. Special attention is paid to two of these approaches, which the authors helped to develop, i.e. diversity-based indices and the Supply/Demand Index. The paper takes issue with conventional welfare economic approaches that neglect: (i) the scope on the demand side for raising security and (ii) negative feedback mechanisms of socio-political impacts of international rent transfers in fossil fuels exporting countries. The concept of energy services security is proposed with a demand-side focus. This enables application of an integrated approach to gauge the resilience of a society to meet the needs of its population for energy services over longer timescales ahead from various interrelated perspectives. Propositions are made on the attribution of security externalities to the use of fossil fuels, policies, and suggestions for further improvements of measures for energy services security.     

Solar orbital power: Sustainability analysis

Solar power plants positioned in space for terrestrial electricity use have been proposed due to the ever-rising world energy consumption and its environmental impacts. This idea is analysed here in the context of sustainability of such power generation. To that end we have performed some new economic, environmental and social effects analysis of electricity generation by solar space power plants of both photovoltaic and solar thermal types power using the best currently available technology. The plants in the analysis were assumed to be in different Earth orbits, or on the Moon built by a robotised factory. One of our results is that both economically and environmentally the best scenario may be to launch a thermal solar power plant to the geostationary orbit from the Moon. Electricity produced in this way could be economically competitive to that generated by fossil fuels on Earth already for as few as 100 space power plants of about 5-10 GW each. This option is also deemed socially responsible with its capacity to reduce poverty with large amounts of cheap clean energy, and environmentally friendly, because it produces more than a hundred times less emissions than the same amount of electricity produced from fossil fuels on Earth.     

Bio-fuels for the gas turbine: A review

Due to depletion of fossil fuel, bio-fuels have generated a significant interest as an alternative fuel for the future. The use of bio-fuels to fuel gas turbine seems a viable solution for the problems of decreasing fossil-fuel reserves and environmental concerns. Bio-fuels are alternative fuels, made from renewable sources and having environmental benefit. In recent years, the desire for energy independence, foreseen depletion of nonrenewable fuel resources, fluctuating petroleum fuel costs, the necessity of stimulating agriculture based economy, and the reality of climate change have created an interest in the development of bio-fuels. The application of bio-fuels in automobiles and heating applications is increasing day by day. Therefore the use of these fuels in gas turbines would extend this application to aviation field. The impact of costly petroleum-based aviation fuel on the environment is harmful. So the development of alternative fuels in aviation is important and useful.The use of liquid and gaseous fuels from biomass will help to fulfill the Kyoto targets concerning global warming emissions. In addition, to reduce exhaust emission waste gases and syngas, etc., could be used as a potential gas turbine fuel. The term bio-fuel is referred to alternative fuel which is produced from biomass. Such fuels include bio-diesel, bio-ethanol, bio-methanol, pyrolysis oil, biogas, synthetic gas (dimethyl ether), hydrogen, etc. The bio-ethanol and bio-methanol are petrol additive/substitute. Bio-diesel is an environment friendly alternative liquid fuel for the diesel/aviation fuel.The gas turbine develops steady flame during its combustion; this feature gives a flexibility to use alternative fuels. Therefore so the use of different bio-fuels in gas turbine has been investigated by a good number of researchers. The suitability and modifications in the existing systems are also recommended.     

Nuclear power for the production of synthetic fuels and feedstocks

Due to depletion of national and foreign resources, development of alternative or synthetic carbonaceous fuels and feedstocks (SCFF) is recommended, using nuclear power not only to provide for the therma, electrical, and hydrogen economies, but also, ultimately, to provide a stable carbonaceous fuel economy. The value or carbonaceous raw material for conversion to SCFF is much higher than burning them for their BTU value alone, and the authors sets forth the process concept for using all forms of carbonaceous materials as sources of raw materials for SCFF. To reduce costs it is recommended to build nuclear plants to provide peaking power for the grids and to utilise the off-peak power for production of SCFF.     

Exergy analysis of renewable energy sources

Oil crises in the past years made more obvious the dependency of economies on fossil fuels. As a consequence, the need for new energy sources became more urgent. Renewable energy sources could provide a solution to the problem, as they are inexhaustible and have less adverse impacts on the environment than fossil fuels. Yet, renewable energy sources technology has not reached a high standard at which it can be considered competitive to fossil fuels. The present study deals with the exergy analysis of solar energy, wind power and geothermal energy. That is, the actual use of energy from the existing available energy is discussed. In addition, renewable energy sources are compared with the non-renewable energy sources on the basis of efficiency.     

Alternative Energy Sources: The Quest for Sustainable Energy [book review]

This book presents a large amount of data dealing with the conventional and alternate energy resources and how they are used. The book is comprised of ten chapters and covers some of the following topics: a discussion about fossil fuels, including coal-fired power plants; sustainable development, and the role of natural gas; environmental impacts of energy consumption; nuclear energy; and renewable energy resources such as solar, wind, hydro, tidal. wave, biomass, and geothermal sources. The book provides lots of data, but not in an organized way. It also appears that the selection of fuels and energy supply alternatives seem to be arbitrary. Despite the book's title, more than half of the pages discuss energy from fossil fuels and their impact on the environment.     

The potential of liquid hydrogen as a military aircraft fuel

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.     

宁夏风力发电前景分析

能源是人类赖以生存的物质基础,是国民经济的基本支撑。中国的能源供应主要依靠煤炭、石油和天然气等化石能源,尤其是宁夏的能源供应主要依靠煤炭,但是化石能源资源的有限性及其开发利用过程对生态环境造成的巨大影响,严重制约经济社会的可持续发展。叙述了宁夏风能资源的现状,分析了风力发电的前景。