The energy consumption and environmental impacts of a color TV set in China

The present study analyses the different processes followed during color TV set production along with the energy consumption and the environment emissions in each stage. The purpose is to identify “hot-spots”, i.e. parts of the life cycle important to the total environmental impact. The analysis is performed using life cycle assessment (LCA) methodology, which is a method used to identify and quantify in the environmental performance of a process or a product from “cradle to grave”. LCA methodology provides a quantitative basis for assessing potential improvements in the environmental performance of a system throughout the life cycle. The system investigated includes the production of manufacturing materials, transport of manufacturing materials, color TV set manufacturing, transport of color TV sets, use of color TV sets, discarding color TV sets and partial plastic waste energy utilization. The environmental burdens that arise from color TV sets are mainly due to air emissions derived from fossil fuel utilization.     

含氧生物质燃料的生命周期评价

为公正评价汽车代用燃料的能耗与环境效益,运用生命周期评价方法,研究了在燃料中分别添加不同比例的乙醇和甲酯2种生物质,带来的生命周期能耗和污染物排放变化,并对含氧生物质燃料的未来情景进行了预测分析.结果表明:乙醇代用燃料未降低化石燃料消耗,甲酯代用燃料可降低约20%的化石燃料消耗;几种配比的代用燃料均可降低石油消耗,甲酯代用燃料降低的趋势更加明显;各种代用燃料的温室气体排放都比较严重;乙醇代用燃料增加了NO_x排放,而甲酯代用燃料可降低约50%的NO_x排放;乙醇和甲酯的加入均能降低车用阶段的PM₁₀排放;燃料生产阶段的SO₂排放在整个生命周期中约占80%,必须严格控制;甲酯代用燃料可降低VOC排放.     

Assessing the environmental impact of metal production processes

Evaluating both new and existing processes for primary metal production to assess their environmental impacts is often difficult due to the many inputs and outputs involved. Life Cycle Assessment (LCA) is a methodology that can be used for such purposes to identify those parts of the metal production life cycle that have significant environmental impacts. LCA has been used by CSIRO Minerals to assess the “cradle-to-gate” environmental impacts of a number of metal production processes practised either currently or potentially in Australia. The metals considered included copper, nickel, aluminium, lead, zinc, steel, stainless steel and titanium, by both pyrometallurgical and hydrometallurgical routes in some instances. The environmental profile included greenhouse and acid rain gas emissions, solid waste emissions and gross energy consumption. The results for various metals are compared in this paper. New process technologies for primary metal production can be expected to reduce the environmental impacts of metal production, and estimates of likely reductions for technologies involving stainless steel, titanium and aluminium are also presented in this paper.     

Leakage of nitrous oxide emissions within the Spanish agro-food system in 1961–2009

In this paper we examine the trends of nitrous oxide (N₂O) emissions of the Spanish agricultural sector related to national production and consumption in the 1961–2009 period. The comparison between production- and consumption-based emissions at the national level provides a complete overview of the actual impact resulting from the dietary choices of a given country and allows the evaluation of potential emission leakages. On average, 1.5 % of the new reactive nitrogen that enters Spain every year is emitted as N₂O. Production- and consumption-based emissions have both significantly increased in the period studied and nowadays consumption-based emissions are 45 % higher than production-based emissions. A large proportion of the net N₂O emissions associated with imported agricultural goods comes from countries that are not committers for the United Nations Framework Convention on Climate Change Kyoto Protocol Annex I. An increase in feed consumption is the main driver of the changes observed, leading to a remarkable emission leakage in the Spanish agricultural sector. The complementary approach used here is essential to achieve an effective mitigation of Spanish greenhouse gas emissions.     

满足城市食物消费需求的农业生产碳排放研究——以宁波为例

食物消费相关的农业生产阶段的碳排放研究,对于探讨气候变化背景下可持续消费模式的选择和低碳农业技术与管理的提升具有重要意义.以宁波市为例,采用生命周期分析与环境投入产出相结合的综合分析框架,对其2012年居民所消费食物在农业生产阶段的直接和间接碳排放进行研究,分析不同食物及不同排放源的排放特征.结果表明,粮食、猪肉、水产品和牛肉对食物消费碳排放总量的贡献最大,分别占28%、25%、10%和9%;粮食、蔬菜和蛋类单位热量和单位蛋白质的碳排放均较小,禽、蛋、水产、鲜奶单位蛋白质的碳排放低于牛羊猪肉;由农业投入品生产所带来的间接碳排放占总量的49%;化肥是多数植物性食物碳排放最大的贡献源,占植物性食物排放总量的33%;饲料是大多动物性食物碳排放的最大来源,占动物性食物排放总量的56%.为促进食物消费和农业生产的碳减排,一方面建议适当增加蛋类、水产品、禽类和鲜奶的消费比重,减少猪牛羊肉的消费比重;另一方面应着重提高农业投入品供应链的能效,推广优化施肥技术与管理,以及提升饲料品质.     

广东电力生产的温室气体排放趋势和演变特征

通过文献调研收集广东电力生产最新的能源消费数据和排放因子,采用“自上而下”方法估算1995—2011年广东电力行业的直接和间接GHG(温室气体)排放量,量化直接排放量的不确定性,绘制GHG排放流向图,并且根据GHG排放特征提出减排建议. 结果表明:①虽然受经济、环境和能源政策的影响,与1995年相比,2011年广东电力生产的GHG总排放量仍增长438%,达3.44×108 t,其中直接排放量达2.78×108 t,不确定性为±11%. ②从发电能源结构角度考虑,燃煤发电是电力生产的最大GHG排放源,2011年其排放量占总排放量的76%;而从用电终端考虑,工业用电是最大的GHG排放源,2011年其排放量占电力生产GHG总排放量的66%. ③1995—2011年,用电终端总体电力GHG排放强度下降了16%,居民用电人均GHG排放量上升了260%,单位综合发电量的GHG排放系数微升了1%. ④发电能源结构和终端产业结构的低碳化以及控制居民用电的GHG排放量等措施可减排2011年广东电力生产GHG总排放量的44%.      

Feeding the world's increasing population while limiting climate change impacts: linking N2O and CH4 emissions from agriculture to population growth

The global demand for agricultural products, including food, is rapidly increasing due to population growth and shifts in consumption patterns. The required increase in agricultural production is predominantly to be achieved in countries with relatively low agricultural production levels at present. These are mainly developing countries and countries in transition, the so-called non-Annex I countries of the UNFCCC. However, intensification of agricultural production systems is currently closely linked to high emissions of greenhouse gases notably nitrous oxide (N₂O) and methane (CH₄). In this paper the relations between population growth, agricultural development and emissions of N₂O and CH₄ were assessed for 10 non-Annex I countries, viz. China, India, Vietnam, Brazil, Argentina, Mexico, Mongolia, Nigeria, Tanzania and South Africa. We combined FAO data on agricultural production levels, CENSUS data on population statistics and EDGAR data on N₂O and CH₄ emissions. The projected trends in agricultural production indicate that emissions of N₂O and CH₄ are expected to increase rapidly in the coming years and will level off from 2040 onwards. The results confirm the positive relation between population increase and increased emissions from agricultural activities for most countries. However, for some countries (South Africa, China and Mexico) this relation was weak or absent. Although numerous factors (e.g. changes in international trade) may have scattered the relation and we were unable to explain this decoupling, it suggests that population growth can be possible without additional emissions. The variation between the different countries and farming systems is however large and mitigation measures at farm-level should be tailored to the wide diversity in environmental conditions, regional customs and farming systems.     

中国油气系统甲烷逸散排放估算

为实现碳达峰碳中和目标,中国正致力于推动能源低碳化转型,这促进能源由煤炭向油气资源的转变.因此,中国石油和天然气系统（油气系统）的甲烷（CH₄）排放日益受到关注.逸散排放包括设备泄漏、排空和火炬燃烧,涉及油气资源的开发、生产、运输、储存和分配等过程.但目前油气系统CH₄逸散排放缺乏统一的核算方法,逸散排放量亦未被纳入国家温室气体清单统计之中.基于相关方法,评估了1980~2020年中国油气系统的CH₄逸散排放.结果表明,油气系统的CH₄逸散排放随着油气资源的生产和消费增长而快速增加,由1980年不足60万t增长至2020年的超过260万t.石油系统和天然气系统在2020年的CH₄逸散排放分别达到约60万t和200万t,是1980年的1.38倍和16.6倍.油气系统的CH₄逸散主要源于天然气生产、石油生产、天然气分配、天然气运输和储存,分别占总排放的41%、20%、18%和13%.天然气管道是主要的逸散设施.相比于常规油气资源开发,非常规油气资源开发的排放强度更高.研究完善了CH₄逸散排放清单,可为CH₄减排提供重要科学数据支持.     

2007年火电行业温室气体排放量估算

为了解我国火电行业温室气体排放情况,参考《IPCC国家温室气体排放清单指南》中固定源燃烧温室气体排放量计算方法学部门方法的相关内容,利用实测的温室气体排放因子以及2007年火电行业活动水平数据,计算火电行业温室气体排放量. 排放因子测算及排放量计算过程均遵循IPCC关于温室气体排放计算的质量保证和质量控制内容. 结果表明,2007年我国火电行业CO₂与N₂O排放量分别为2.81×109和1.56×105 t.同时使用参考方法,利用国家级能源统计数据直接计算火电行业CO₂排放量.将部门方法与参考方法计算结果进行比对发现,原煤、原油和天然气燃烧温室气体排放量2种方法的相对偏差分别为7.5%,98.8%和1.6%,除原油外,原煤和天然气燃烧CO₂排放量与参考方法相差并不大.      

Major challenges of integrating agriculture into climate change mitigation policy frameworks

Taking the European Union (EU) as a case study, we simulate the application of non-uniform national mitigation targets to achieve a sectoral reduction in agricultural non-carbon dioxide (CO₂) greenhouse gas (GHG) emissions. Scenario results show substantial impacts on EU agricultural production, in particular, the livestock sector. Significant increases in imports and decreases in exports result in rather moderate domestic consumption impacts but induce production increases in non-EU countries that are associated with considerable emission leakage effects. The results underline four major challenges for the general integration of agriculture into national and global climate change mitigation policy frameworks and strategies, as they strengthen requests for (1) a targeted but flexible implementation of mitigation obligations at national and global level and (2) the need for a wider consideration of technological mitigation options. The results also indicate that a globally effective reduction in agricultural emissions requires (3) multilateral commitments for agriculture to limit emission leakage and may have to (4) consider options that tackle the reduction in GHG emissions from the consumption side.     

2011年中国钢铁行业典型有害重金属大气排放清单

根据中国钢铁工业年鉴等统计资料,采用排放因子法,对2011年我国钢铁行业生产活动导致的汞(Hg)、铅(Pb)、镉(Cd)、砷(As)、铬(Cr)、镍(Ni)等6种有害重金属的大气排放及其分布特征进行了研究,并给出了分省区排放清单.结果表明,2011年中国钢铁行业汞、铅、镉、砷、铬、镍大气排放量分别约为18.8, 3745.8, 39.4, 132.2, 241.2, 105.3t;钢铁行业重金属大气排放集中在环渤海经济圈以及长三角地区,其中河北东部及中南部、山东中部等钢铁冶炼企业集中地区重金属大气排放强度较大;钢铁企业内部炼钢工艺对重金属大气排放贡献率较高,其中转炉工序对砷、铅排放贡献率较大,电炉工序对于镉、镍贡献率较大.     

Life-cycle inventory for hydroelectric generation: a Brazilian case study

Representative Life-Cycle Inventories (LCIs) are essential for Life-Cycle Assessments (LCAs) quality and readiness. Because energy is such an important element of LCAs, appropriate LCIs on energy are crucial, and due to the prevalence of hydropower on Brazilian electricity mix, the frequently used LCIs are not representative of the Brazilian conditions. The present study developed a LCI of the Itaipu Hydropower Plant, the major hydropower plant in the world, responsible for producing 23.8% of Brazil's electricity consumption. Focused on the capital investments to construct and operate the dam, the LCI was designed to serve as a database for the LCAs of Brazilian hydroelectricity production. The life-cycle boundaries encompass the construction and operation of the dam, as well as the life-cycles of the most important material and energy consumptions (cement, steel, copper, diesel oil, lubricant oil), as well as construction site operation, emissions from reservoir flooding, material and workers transportation, and earthworks. As a result, besides the presented inventory, it was possible to determine the following processes, and respective environmental burdens as the most important life-cycle hotspots: reservoir filling (CO₂ and CH₄ emission; land use); steel life-cycle (water and energy consumption; CO, particulates, SO_x and NO_x emissions); cement life-cycle (water and energy consumption; CO₂ and particulate emissions); and operation of civil construction machines (diesel consumption; NO_x emissions). Compared with another hydropower studies, the LCI showed magnitude adequacy, with better results than small hydropower, which reveals a scale economy for material and energy exchanges in the case of Itaipu Power Plant.     

Attributional life cycle assessment of woodchips for bioethanol production

Besides the apparent need to reduce greenhouse gas emissions, other important factors contributing to the renewed interest in biofuels are energy security concerns and the need of sustainable transportation fuel. Nearly 30% of the annual CO₂ emissions in the U.S. come from the transportation sector and more than half of the fuel is imported. Biofuels appear to be a promising option to reduce carbon dioxide emissions, and the reliance on imported oil concomitantly. The interest on (ligno) cellulosic ethanol is gaining momentum as corn-based ethanol is criticized for using agricultural outputs for fuel production. Among many lignocellulosic feedstocks, woodchips is viewed as one of the most promising feedstocks for producing liquid transportation fuels. The renewable and carbon neutral nature of the feedstocks, similar chemical and physical properties to gasoline, and the low infrastructure cost due to the availability of fuel flex vehicles and transportation networks make (ligno) cellulosic bioethanol an attractive option. An in-depth LCA of woodchips shows that harvesting and woodchips processing stage and transportation to the facility stage emit large amount of environmental pollutants compared to other life cycle stages of ethanol production. Our analysis also found that fossil fuel consumption and respiratory inorganic effects are the two most critical environmental impact categories in woodchips production. We have used Eco-indicator 99 based cradle-to-gate LCA method with a functional unit of 4 m³ of dry hardwood chips production.     

Practical experiences with the implementation of the concept of zero emissions in the surface treatment industry in Austria

The authors have developed the approach of the “Zero emission retrofitting method for existing galvanizing plants” (ZERMEG). The goal of this approach is to take existing galvanizing plants as far as possible towards zero emissions. The development was supported by the Austrian ministry for science and technology within the programme “Factory of the Future”. The method consists first of an analytical step to describe the existing performance of the plant in terms of production, water input and input of chemicals, a second step is designed to characterize the theoretically possible minimum consumption using the present equipment and the third step is the comparison of the present to the ideal situation to identify optimisation options (improved draining, dosage of chemicals, control of rinsing water, mixing in the tanks, etc.).To facilitate the calculations, a Microsoft-Excel-programme was developed (Zero Emission Program Analysis, ZEPRA), which allows to calculate the ideal water consumption of different configurations of rin ses, drag out for different shapes and surface conditions of parts, and changes in concentrations of active baths. A technology data bank was developed that includes information on different technologies to enlarge the useful time of galvanizing baths or to recycle spent solutions and rinsing water.This paper describes case studies in five galvanizing plants. The measures which were implemented include changing the rinsing cascades in three plants at the wire producer Pengg (reduction of the water consumption in the batch pickling plant by 50%), the use of spent caustics to preneutralise spent process baths and the implementation of an electrolysis plant to recover copper at the printed circuit board manufacturer AT&S (recovery of 20 kg/day of copper), optimising the pickling baths of the hot dip galvanizer Mosdorfer (50% reduction of consumption of acids) and the optimisation of the spray rinses in the automatic copper plating plants of the producer of printing cyclinders Rotoform (reduction of water consumption by 50%, reduction of acid consumption by 40%).The work showed, that in three of the five plants it was possible to fully avoid the discharge of spent process baths. One plant now operates at zero emissions. In one plant it would be technically feasible to do so, however, it is not economically feasible, at this time.     

Managing the nitrogen cycle to reduce greenhouse gas emissions from crop production and biofuel expansion

Public policies are promoting biofuels as an alternative to fossil fuel consumption in order to mitigate greenhouse gas (GHG) emissions. However, the mitigation benefit can be at least partially compromised by emissions occurring during feedstock production. One of the key sources of GHG emissions from biofuel feedstock production, as well as conventional crops, is soil nitrous oxide (N₂O), which is largely driven by nitrogen (N) management. Our objective was to determine how much GHG emissions could be reduced by encouraging alternative N management practices through application of nitrification inhibitors and a cap on N fertilization. We used the US Renewable Fuel Standards (RFS2) as the basis for a case study to evaluate technical and economic drivers influencing the N management mitigation strategies. We estimated soil N₂O emissions using the DayCent ecosystem model and applied the US Forest and Agricultural Sector Optimization Model with Greenhouse Gases (FASOMGHG) to project GHG emissions for the agricultural sector, as influenced by biofuel scenarios and N management options. Relative to the current RSF2 policy with no N management interventions, results show decreases in N₂O emissions ranging from 3 to 4 % for the agricultural sector (5.5–6.5 million metric tonnes CO₂?eq.?year^?1; 1 million metric tonnes is equivalent to a Teragram) in response to a cap that reduces N fertilizer application and even larger reductions with application of nitrification inhibitors, ranging from 9 to 10 % (15.5–16.6 million tonnes CO₂?eq.?year^?1). The results demonstrate that climate and energy policies promoting biofuel production could consider options to manage the N cycle with alternative fertilization practices for the agricultural sector and likely enhance the mitigation of GHG emissions associated with biofuels.     

Food security and global environmental change: emerging challenges

Most research linking global environmental change and food security focuses solely on agriculture: either the impact of climate change on agricultural production, or the impact of agriculture on the environment, e.g. on land use, greenhouse gas emissions, pollution and/or biodiversity. Important though food production is, many other factors also need to be considered to understand food security. A recent international conference on “Environmental Change and Food Security: Bridging Science, Policy and Development for Adaptation” included a range of papers that embraced the multiple dimensions of the food systems that underpin food security. The major conclusion from the conference was that technical fixes alone will not solve the food security challenge. Adapting to the additional threats to food security arising from major environmental changes requires an integrated food system approach, not just a focus on agricultural practices. Six key issues emerged for future research: (i) adapting food systems to global environmental change requires more than just technological solutions to increase agricultural yields; (ii) tradeoffs across multiple scales among food system outcomes are a pervasive feature of globalized food systems; (iii) within food systems, there are some key underexplored areas that are both sensitive to environmental change but also crucial to understanding its implications for food security and adaptation strategies; (iv) scenarios specifically designed to investigate the wider issues that underpin food security and the environmental consequences of different adaptation options are lacking; (v) price variability and volatility often threaten food security; and (vi) more attention needs to be paid to the governance of food systems.     

Environmental impact of the substitution of imported soybean meal with locally-produced rapeseed meal in dairy cow feed

Growing public concerns about the traceability, safety and environmental-friendliness of food products provide an incentive for shorter supply chains in agricultural production. Here, we assessed the environmental impacts of the substitution of imported soybean meal with locally-produced rapeseed meal in French dairy production systems, using a life-cycle approach. Two feeding rations based on either French-produced rapeseed meal or Brazilian-produced soy meal as concentrates, were compared for nine impact categories, including global warming, ecotoxicity and eutrophication. Crop production was the main contributor to most impacts, while overseas transport of soy meal only had a marginal effect. The “Soybean” ration appeared more environmentally-efficient than the “Rapeseed” ration because it involved less intensive management practices, in particular regarding synthetic fertilizers consumption. However, land use changes brought about by soybean cultivation should also be examined.     

中国氢燃料电池车燃料生命周期的化石能源消耗和CO2排放

氢燃料电池车(FCV)具有运行阶段高能效和零排放的优点,近年来得到快速的商业化发展.氢能生产具有多种技术路径,不同路径的能源和环境效益存在显著差异.本研究采用生命周期评价方法,运用GREET模型对不同氢燃料路径下的FCV燃料周期(WTW)的化石能源消耗和CO_2排放进行了全面评价.选取了多种制氢路径作为评价对象,建立了中国本地化的FCV燃料生命周期数据库,在此基础上分析了FCV相对传统汽油车的WTW节能减排效益,并和混合动力车和纯电动车进行比较.结果表明,使用可再生电力和生物质等绿色能源制氢供应FCV能取得显著的WTW节能减排效益,可削减约90%的化石能耗和CO_2排放.在发展相对成熟的传统能源制氢路径中,以焦炉煤气制得氢气为原料的FCV,能产生显著的节能减排效益,其化石能耗低于混合动力车,CO_2排放低于混合动力车和纯电动车.结合对资源储备和技术成熟度的考虑,我国在发展氢能及FCV过程中,近期可考虑利用焦炉煤气等工业副产物制氢,并且规划中远期的绿色制氢技术发展.     

我国典型露地蔬菜生产中的温室气体排放

基于国家农业统计数据,以露地番茄、黄瓜、大白菜和萝卜为研究对象,应用生命周期评价(life cycle assessment,LCA)方法,定量化我国4种典型露地蔬菜生产中的净温室气体排放(net greenhouse gas emission,NGHGE),并比较蔬菜种类间、省域间净温室气体排放差异和分析减排措施.结果表明:我国典型露地蔬菜生产系统温室气体排放量远高于其带来的碳固定量,是净温室气体排放系统,生产单位面积露地番茄、黄瓜、大白菜和萝卜净温室气体排放(以CO_2-eq计)分别为4 149、 3 718、 3 780和2 427 kg·hm~(-2),不同种类露地蔬菜净温室气体排放差异大;我国典型露地蔬菜净温室气体排放空间差异大,其中,海南、云南、陕西和山东等省份番茄、黄瓜、大白菜和萝卜净温室气体排放高;肥料生产运输和施用是露地蔬菜温室气体排放的主要贡献因子,贡献率为86.8%～90.8%,因此改善肥料生产工艺降低肥料生产运输过程中的温室气体排放和根据露地蔬菜种类及种植地区优化肥料施用量是实现我国露地蔬菜可持续发展的重要措施.     

中国化石能源生命周期清单分析

利用生命周期评价方法,建立了我国化石能源的生命周期清单模型,详述了模型相关因子的确定方法,计算了原煤、原油、天然气等初级能源及汽油、焦炭等几类主要次级能源的生命周期清单,揭示了我国能源生产的环境负荷,为工业系统分析和材料、产品的生命周期评价提供基础数据.清单分析表明我国化石能源清单的主要特点为能源消耗的97%以上主要来自生产过程,运输占到3%左右的比例;通过与2002年清单相比,我国化石能源生产的总能耗和排放出现不同程度变化;通过与国外能源清单相比,我国能源投入及排放整体处于较高水平.