共查询到20条相似文献，搜索用时 593 毫秒
1.
We analyzed the mortality impacts and greenhouse gas (GHG) emissions produced by household energy use in Africa. Under a business-as-usual (BAU) scenario, household indoor air pollution will cause an estimated 9.8 million premature deaths by the year 2030. Gradual and rapid transitions to charcoal would delay 1.0 million and 2.8 million deaths, respectively; similar transitions to petroleum fuels would delay 1.3 million and 3.7 million deaths. Cumulative BAU GHG emissions will be 6.7 billion tons of carbon by 2050, which is 5.6% of Africa's total emissions. Large shifts to the use of fossil fuels would reduce GHG emissions by 1 to 10%. Charcoal-intensive future scenarios using current practices increase emissions by 140 to 190%; the increase can be reduced to 5 to 36% using currently available technologies for sustainable production or potentially reduced even more with investment in technological innovation. 相似文献
2.
Advanced technology paths to global climate stability: energy for a greenhouse planet 总被引：6，自引：0，他引：6
Hoffert MI Caldeira K Benford G Criswell DR Green C Herzog H Jain AK Kheshgi HS Lackner KS Lewis JS Lightfoot HD Manheimer W Mankins JC Mauel ME Perkins LJ Schlesinger ME Volk T Wigley TM 《Science (New York, N.Y.)》2002,298(5595):981-987
Stabilizing the carbon dioxide-induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (approximately 10(13) watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission-free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non-primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development. 相似文献
3.
Nadine Lehrer 《Agriculture and Human Values》2010,27(4):427-444
In the mid-2000s, rising gas prices, political instability, pollution, and fossil fuel depletion brought renewable domestic
energy production onto the policy agenda. Biofuels, or fuels made from plant materials, came to be seen as America’s hope
for energy security, environmental conservation, and rural economic revitalization. Yet even as the actual environmental,
economic, and energy contributions of a biofuels boom remained debatable, support for biofuels swelled and became a prominent
driver of not only US energy policy but of US farm policy as well. This paper asks why biofuels became such a powerful force
in farm policy debates, and draws on policy windows theory and discourse analysis to analyze biofuels’ contributions to the
passage of the 2008 farm bill. It finds that budgetary and political factors combined with a particular set of patriotic biofuels-oriented
discourses to carry energy policy debates into farm policy. It also comments on the implications of biofuels policies for
conservation and sustainable land use in 2008 and beyond. 相似文献
4.
《农业科学与工程前沿(英文版)》2015,(1)
The major source of energy comes from fossil fuels.The current situation in the fi eld of fuel and energy is becoming more problematic as world population continues to grow because of the limitation of fossil fuels reserve and its pressure on environment.This review aims to fi nd economic,reliable,renewable and non-polluting energy sources to reduce high energy tariffs in Russian Federation.Biofuel is fuel derived directly from plants,or indirectly from agricultural,commercial,domestic,and/or industrial wastes.Other alternative energy sources including solar energy and electric power generation are also discussed.Over 100 Mt of biomass available for energy purposes is produced every year in Russian.One of the downsides of biomass energy is its potential threatens to food security and forage industries.An innovative approach proved that multicomponent fuel(80%diesel oil content for motor and 64%for in stove fuel)can remarkably reduce the costs.This paper proposed that the most promising energy model for future is based on direct solar energy conversion and transcontinental terawatt power transmission with the use of resonant wave-guide technology. 相似文献
5.
Biofuels derived from low-input high-diversity (LIHD) mixtures of native grassland perennials can provide more usable energy, greater greenhouse gas reductions, and less agrichemical pollution per hectare than can corn grain ethanol or soybean biodiesel. High-diversity grasslands had increasingly higher bioenergy yields that were 238% greater than monoculture yields after a decade. LIHD biofuels are carbon negative because net ecosystem carbon dioxide sequestration (4.4 megagram hectare(-1) year(-1) of carbon dioxide in soil and roots) exceeds fossil carbon dioxide release during biofuel production (0.32 megagram hectare(-1) year(-1)). Moreover, LIHD biofuels can be produced on agriculturally degraded lands and thus need to neither displace food production nor cause loss of biodiversity via habitat destruction. 相似文献
6.
Increased demand for liquid transportation fuels, environmental concerns and depletion of petroleum resources requires the development of efficient conversion technologies for production of second-generation biofuels from non-food resources. Thermochemical approaches hold great potential for conversion of lignocellulosic biomass into liquid fuels. Direct thermochemical processes convert biomass into liquid fuels in one step using heat and catalysts and have many advantages over indirect and biological processes, such as greater feedstock flexibility, integrated conversion of whole biomass, and lower operation costs. Several direct thermochemical processes are employed in the production of liquid biofuels depending on the nature of the feedstock properties: such as fast pyrolysis/liquefaction of lignocellulosic biomass for bio-oil, including upgrading methods, such as catalytic cracking and hydrogenation. Owing to the substantial amount of liquid fuels consumed by vehicular transport, converting biomass into drop-in liquid fuels may reduce the dependence of the fuel market on petroleumbased fuel products. In this review, we also summarize recent progress in technologies for large-scale equipment for direct thermochemical conversion. We focus on the technical aspects critical to commercialization of the technologies for production of liquid fuels from biomass,including feedstock type, cracking catalysts, catalytic cracking mechanisms, catalytic reactors, and biofuel properties. We also discuss future prospects for direct thermochemical conversion in biorefineries for the production of high grade biofuels. 相似文献
7.
Goldemberg J 《Science (New York, N.Y.)》1978,200(4338):158-164
Brazil's energy options and current outlook are examined, and a summary of known reserves of fossil and renewable energy resources is given. Brazil has abundant renewable energy resources but very modest reserves of fossil fuels. Consequently, the emphasis in the future will have to be on the utilization of solar energy, hydroelectric power, and biomass in a program designed to preserve local traditions and culture. 相似文献
8.
为探究生物质能源化利用中灰分含量和热值的函数变化规律及测定方法,检索2001—2021年已发表的相关文献,获得380个不同类型的生物质样本的灰分含量和高位热值数据,并对测定方法进行分析。结果表明：1）不同热值测定标准对热值的测定结果的评价影响可以忽略不计,而根据固体矿物燃料标准测定的灰分含量结果会显著低于按照生物质燃料标准的测定结果;2）草本植物类生物质的灰分含量为7.96%～9.19%,高于木本植物的2.26%～3.37%,但其平均热值（17.45MJ/kg）却低于木本植物（19.61MJ/kg）;3）草本植物的高位热值与灰分含量呈负相关,相关系数（r）的绝对值为0.567～0.918,高于木本植物的0.136。高位热值与化学元素（碳、氢、氮、硫、氧）含量的决定系数（R2）为0.936 7～0.973 7,高于与灰分、挥发分和固定碳含量的决定系数0.812 0～0.971 4,前者函数的拟合效果更好;4）应用近红外光谱技术建立的生物质水分、灰分含量和热值模型的预测偏差较小,小于参考方法的重复性界限,因此该测定方法更便捷,在生物质产业中具有很大的应用潜力。 相似文献
9.
温室气体排放清单是目前最常用的城市碳排放核算方法,有助于在大尺度上了解城市不同行业或部门的温室气体排放情况.然而,中国城市温室气体清单研究刚刚起步,研究成果还不多,尚缺乏系统、规范的城市温室气体研究方法和指标体系.概述了城市温室气体排放清单的主要参考编制方法,介绍了国内外城市温室气体清单的编制情况,对目前城市温室气体清单编制的特点进行了分析,总结了城市温室气体清单与国家温室气体清单在关键排放源、编制模式、方法体系等方面的差异;在此基础上结合我国城市实际,对适合中国城市的温室气体清单编制方法进行了探索,并针对清单编制过程中存在的具体问题提出了建议;最后对未来城市温室气体清单的发展趋势进行了展望,以期为中国温室气体清单编制及研究提供借鉴. 相似文献
10.
Revelle R 《Science (New York, N.Y.)》1980,209(4452):164-174
Outside of China, the countries of southern and eastern Asia contain 30 percent of the world's population but only 2 percent of the known fossil fuel resources. Economic growth has resulted in increasing imports of petroleum and petroleum products. Because of the tenfold rise in oil prices since 1972, several of these countries are faced with two dilemmas-one short range and one long range. Unless they can discover more fossil fuel resources within their own borders, they must either incur dangerously growing foreign exchange deficits or drastically slow their economic growth. Research and development in energy production, conversion, and conservation should eventually allow local energy sources, of which the most promising is biomass energy, to be substituted for imported fuels. But diverting scarce land and water to plantations of fast-growing trees or other kinds of biomass may seriously limit food production in these crowded countries. 相似文献
11.
低碳竞争力是一个国家或地区所反映出来的在低碳效率、低碳环境、低碳科技等方面的综合水平的一种竞争优势或能力.中国西部地区正面临着跨越式发展和可持续发展两大任务,面对新一轮西部大开发的战略机遇,在全球向低碳转型背景下西部地区必须转变发展方式,走低碳发展路径,充分发挥后发优势以提升其低碳竞争力,才能实现资源节约型、环境友好型以及气候安全型社会建设目标.在构建低碳竞争力评价指标体系基础上,采用PCA、熵值法和聚类分析法对西部12个省(区,市)低碳竞争力进行评价.研究结果表明:(1)西部地区的低碳经济发展水平可以划分为3个层次:重庆、陕西、广西、四川属于相对低碳地区;云南、新疆、宁夏、贵州、内蒙、西藏属于中碳地区;青海、甘肃属于相对高碳地区.(2)重庆、陕西、云南等作为国家发改委批准的首批全国低碳试点省市,其低碳竞争力排位明显比较靠前,说明低碳试点工作成效显著.(3)单位GDP综合能耗低的省区,综合排名也比较高,因而降低单位GDP综合能耗是提升低碳竞争力的必然选择.(4)低碳竞争力的影响因素复杂.尤其是第一主成分中的X1(单位GDP综合能耗)、X8(森林覆盖率)载荷系数相对较大,进一步说明要实现低碳发展,除了通过节能减排以减少“碳源”外,还要大力增加“碳汇”.(5)低碳竞争力是一个相对的概念,西部地区应发挥协同竞争优势,加强在低碳领域的合作与交流,实现在竞争中合作、在合作中发展. 相似文献
12.
Li H Opgenorth PH Wernick DG Rogers S Wu TY Higashide W Malati P Huo YX Cho KM Liao JC 《Science (New York, N.Y.)》2012,335(6076):1596
One of the major challenges in using electrical energy is the efficiency in its storage. Current methods, such as chemical batteries, hydraulic pumping, and water splitting, suffer from low energy density or incompatibility with current transportation infrastructure. Here, we report a method to store electrical energy as chemical energy in higher alcohols, which can be used as liquid transportation fuels. We genetically engineered a lithoautotrophic microorganism, Ralstonia eutropha H16, to produce isobutanol and 3-methyl-1-butanol in an electro-bioreactor using CO(2) as the sole carbon source and electricity as the sole energy input. The process integrates electrochemical formate production and biological CO(2) fixation and higher alcohol synthesis, opening the possibility of electricity-driven bioconversion of CO(2) to commercial chemicals. 相似文献
13.
14.
We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government. 相似文献
15.
Häfele W 《Science (New York, N.Y.)》1980,209(4452):174-182
Most studies of energy supply and demand ignore either global inter-dependence or the long time spans necessary to adjust to new energy sources. The International Institute for Applied Systems Analysis has therefore studied on a global scale, for seven major world regions, the balance between energy supply and demand for the next 50 years. Reported here are the results for two benchmark scenarios. In the "low" scenario world energy consumption increases from today's 8.2 terawatt-year per year to 22 terawatt-year per year in 2030; in the "high" scenario, consumption increases to 35 terawatt-year per year. The study showed that time will be the limiting constraint in adapting the energy supply infrastructure to changing resource availability; resources will be available until the second half of the next century, but a strong shift will be required to low-grade fossil fuels such as shale oil and tar sands. Each scenario studied indicated increased environmental problems associated with increased use of fossil fuels, and potential geopolitical problems associated with the world distribution of resources. 相似文献
16.
化石燃料的持续开采与使用对环境产生了严重的负面影响，使得开发可再生清洁能源代替传统能源成为必然。木质纤维素是一种丰富的可再生资源，可转化为生物乙醇、氢气等生物质燃料，被认为是代替化石燃料的理想替代品。其中木质纤维原料转化为生物乙醇需经过预处理、酶水解以及微生物发酵这3个关键步骤，而纤维素酶水解通常会受到酶、水解条件、底物等诸多因素的影响。针对木质素对纤维素酶水解的影响研究进行综述，大量研究发现，木质素是纤维素酶水解过程中的主要抑制剂。木质素既可以吸附纤维素酶，与纤维素酶发生无效吸附；又可以作为物理屏障，阻碍酶对纤维素的生产性吸附。尽管通过预处理可以去除大部分的木质素，但依旧无法从根源上缓解木质素对纤维素酶水解的影响，研究木质素的结构单元对酶解效率的影响可能是当前生物乙醇转化中木质素在纤维素酶水解中的研究方向。 相似文献
17.
Woodwell GM Hobbie JE Houghton RA Melillo JM Moore B Peterson BJ Shaver GR 《Science (New York, N.Y.)》1983,222(4628):1081-1086
A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1860 and 1980 was between 135 x 10(15) and 228 x 10(15) grams. Between 1.8 x 10(15) and 4.7 x 10(15) grams of carbon were released in 1980, of which nearly 80 percent was due to deforestation, principally in the tropics. The annual release of carbon from the biota and soils exceeded the release from fossil fuels until about 1960. Because the biotic release has been and remains much larger than is commonly assumed, the airborne fraction, usually considered to be about 50 percent of the release from fossil fuels, was probably between 22 and 43 percent of the total carbon released in 1980. The increase in carbon dioxide in the atmosphere is thought by some to be increasing the storage of carbon in the earth's remaining forests sufficiently to offset the release from deforestation. The interpretation of the evidence presented here suggests no such effect; deforestation appears to be the dominant biotic effect on atmospheric carbon dioxide. If deforestation increases in proportion to population, the biotic release of carbon will reach 9 x 10(15) grams per year before forests are exhausted early in the next century. The possibilities for limiting the accumulation of carbon dioxide in the atmosphere through reduction in use of fossil fuels and through management of forests may be greater than is commonly assumed. 相似文献
18.
基于《全国农产品成本收益资料汇编》以及收集的相关参数数据,采用生命周期评价法分析2004-2013年山西省小麦生产中不同功能单位的碳足迹变化动态并解析其构成,以期为山西省小麦的低碳清洁化生产与气候变化的缓解提供一定的理论依据。结果表明：山西省小麦生产的温室气体排放从2004年的3 798.5 kg/hm2（CO2-eq）增加到2013年的4 650.5 kg/hm2（CO2-eq）,年均增加74.9 kg/hm2（CO2-eq）;肥料应用（尤其是氮肥和复合肥）、土壤N2O以及机械操作的能源消耗是其主要构成,占总排放的90%以上。山西省小麦的产量碳足迹总体上变化不大,而产值碳足迹、成本碳足迹以及净利润碳足迹均表现为逐渐降低的趋势,其中成本碳足迹达到显著水平。考虑土壤有机碳储量变化后,不同功能单位的小麦碳足迹均大幅度降低。综上所述,合理施肥、加强机械一体化推广以及增加土壤固碳是降低山西省小麦碳足迹的主要途径。 相似文献
19.
中国生物质能源发展现状及问题探讨 总被引：3，自引：0，他引：3
当前世界正面临着严重的化石能源危机,生物质能源发展已受到越来越多国家的关注。文章综述了生物燃气、生物液体燃料、微藻能源、固体成型燃料等生物质能源技术的主要进展,分析了我国生物质能源产业发展中出现的一些问题,并基于此提出了完善和修改生物质能源产品价格补贴、强制性生物质液体燃料收购、鼓励生物质液体燃料消费等激励政策,设立专项加快开发和应用具有自主知识产权的国产化技术,以及大力度发展非粮生物质能源和利用边际土地建立生物质能源基地等政策建议。 相似文献
20.
我国生物质能源产业科技创新发展对策研究 总被引：1，自引：0，他引：1
随着化石能源的过度开采和使用,世界各国面临着不同程度的化石能源短缺和生态危机,开发和利用清洁可再生能源已成为各国关注的焦点,对于正处于经济结构转型时期的我国也有重要的战略意义,不仅可以缓解能源短缺,而且其双向清洁性对于保护生态环境和减排温室气体具有现实意义。深入剖析了在我国发展生物质能源产业的战略意义、面临的机遇及挑战,提出了对策措施和政策建议,对生物质能源产业在我国的发展具有一定的参考意义。 相似文献