能源结构与CO_2排放的定量关联机制研究

识别能源结构调整对CO2排放的定量影响可以为评估国家相关温室气体控制政策提供数理工具。首先基于中国的实际能源结构,对不同能源的标准煤CO2排放系数进行了测算和适用范围界定,在此基础上,定量分析了中国"十一五"期间能源结构调整对CO2排放的影响,指出了中国节能措施和能源结构调整措施对CO2排放影响的贡献率。通过对能源结构调整与CO2排放的敏感性定量测算,可知非化石能源替代煤炭具有最佳的CO2排放降低效益。在定量分析基础上,提出了基于能源结构的降低CO2排放的针对性措施和政策建议。     

对稳定浓度目标下温室气体排放路径的探讨

为研究稳定浓度目标下温室气体排放路径的不确定性问题,应用温室气体导致气候变化评估模型( MAGICC模型)和WRE排放情景的数据对2100年温室气体浓度控制在450和550 ppmvCO2当量目标下的排放路径及浓度变化情况进行了研究.结果显示,目标年浓度的变化取决于起始年至目标年的累计排放量和摊放路径.将排放路径峰值逐渐调整滞后时,为保证累计排放量不变,需在到达峰值后比原排放路径进行更大力度的减排.温室气体浓度在预测期内将逐渐增加,但目标年的结果变化较小,约为浓度变化最大值的1/3左右.将WRE350和WRE450排放路径的峰值分别调整至2020年和2035年时,与原排放路径相比,浓度改变的最大值分别为6.4 ppmv和22.8 ppmv,而2100年浓度的改变值分别为1.9 ppmv和7.5 ppmv.     

GHG emission factors developed for the recycling and composting of municipal waste in South African municipalities

GHG (greenhouse gas) emission factors for waste management are increasingly used, but such factors are very scarce for developing countries. This paper shows how such factors have been developed for the recycling of glass, metals (Al and Fe), plastics and paper from municipal solid waste, as well as for the composting of garden refuse in South Africa. The emission factors developed for the different recyclables in the country show savings varying from ?290 kg CO₂ e (glass) to ?19 111 kg CO₂ e (metals – Al) per tonne of recyclable. They also show that there is variability, with energy intensive materials like metals having higher GHG savings in South Africa as compared to other countries. This underlines the interrelation of the waste management system of a country/region with other systems, in particular with energy generation, which in South Africa, is heavily reliant on coal. This study also shows that composting of garden waste is a net GHG emitter, releasing 172 and 186 kg CO₂ e per tonne of wet garden waste for aerated dome composting and turned windrow composting, respectively. The paper concludes that these emission factors are facilitating GHG emissions modelling for waste management in South Africa and enabling local municipalities to identify best practice in this regard.     

Pyrolysis and gasification of meat-and-bone-meal: Energy balance and GHG accounting

Meat-and-bone-meal (MBM) produced from animal waste has become an increasingly important residual fraction needing management. As biodegradable waste is routed away from landfills, thermo-chemical treatments of MBM are considered promising solution for the future. Pyrolysis and gasification of MBM were assessed based on data from three experimental lab and pilot-scale plants. Energy balances were established for the three technologies, providing different outcomes for energy recovery: bio-oil was the main product for the pyrolysis system, while syngas and a solid fraction of biochar were the main products in the gasification system. These products can be used – eventually after upgrading – for energy production, thereby offsetting energy production elsewhere in the system. Greenhouse gases (GHG) accounting of the technologies showed that all three options provided overall GHG savings in the order of 600–1000 kg CO₂-eq. per Mg of MBM treated, mainly as a consequence of avoided fossil fuel consumption in the energy sector. Local conditions influencing the environmental performance of the three systems were identified, together with critical factors to be considered during decision-making regarding MBM management.     

A multi-objective programming model for assessment the GHG emissions in MSW management

In this study a multi-objective mathematical programming model is developed for taking into account GHG emissions for Municipal Solid Waste (MSW) management. Mathematical programming models are often used for structure, design and operational optimization of various systems (energy, supply chain, processes, etc.). The last twenty years they are used all the more often in Municipal Solid Waste (MSW) management in order to provide optimal solutions with the cost objective being the usual driver of the optimization. In our work we consider the GHG emissions as an additional criterion, aiming at a multi-objective approach. The Pareto front (Cost vs. GHG emissions) of the system is generated using an appropriate multi-objective method. This information is essential to the decision maker because he can explore the trade-offs in the Pareto curve and select his most preferred among the Pareto optimal solutions. In the present work a detailed multi-objective, multi-period mathematical programming model is developed in order to describe the waste management problem. Apart from the bi-objective approach, the major innovations of the model are (1) the detailed modeling considering 34 materials and 42 technologies, (2) the detailed calculation of the energy content of the various streams based on the detailed material balances, and (3) the incorporation of the IPCC guidelines for the CH₄ generated in the landfills (first order decay model). The equations of the model are described in full detail. Finally, the whole approach is illustrated with a case study referring to the application of the model in a Greek region.     

亏缺灌溉对冬小麦农田温室气体排放的影响

为研究不同时期亏水量对冬小麦农田土壤温室气体排放的影响,优化灌溉管理措施,试验采用静态箱-气相色谱法对关中平原冬小麦(2016年10月～2017年6月)农田温室气体(CO_2、N_2O和CH_4)排放通量进行了监测研究.试验在冬小麦3个生育期(越冬期、拔节至抽穗期、抽穗至灌浆期)各设置3个灌水水平(充分灌溉,100%;轻度水分亏缺,80%;重度水分亏缺,60%),共6个处理(CK、T1、T2、T3、T4、T5,其中CK处理为充分灌溉处理,其它处理均为不同程度的水分亏缺处理).阐述了3种气体(CO_2、N_2O和CH_4)在全生育期的动态变化特征,并用作物产量、长远增温效应(net GWP_L)和当季增温效应(net GWPS)这3个指标综合评估不同生育期亏水水平对关中平原小麦经济效应和生态效应的影响.结果表明,生育期灌溉后CO_2、N_2O排放通量基本上呈增加趋势,以CK处理最高,而灌溉后土壤CH_4吸收通量迅速减小,高水分处理甚至出现排放特征.与CK处理相比,T1、T2、T3、T4和T5处理下小麦季CO_2排放总量分别显著降低了13. 32%、25. 98%、5. 55%、15. 47%和17. 52%(P 0. 05),N_2O排放总量分别显著降低了12. 20%、18. 00%、5. 63%、11. 54%和13. 53%(P 0. 05),CH_4吸收总量分别显著增加了46. 47%、75. 78%、19. 47%、53. 40%和62. 33%(P 0. 05); T1、T2、T3、T4和T5处理net GWP_L较CK处理分别显著降低了10. 07%、12. 77%、6. 50%、6. 81%和11. 53%(P 0. 05);除T3处理外,其他处理较CK处理net GWPS分别显著降低了13. 21%、37. 65%、24. 60%和19. 86%(P 0. 05); T1、T2、T3、T4和T5处理小麦产量较CK处理分别显著减少了12. 56%、32. 53%、2. 25%、20. 93%和18. 14%(P 0. 05),T3处理较CK处理减产2. 25%,但无显著性差异(P 0. 05).亏缺灌溉显著降低了小麦地温室气体的排放,但会造成不同程度的减产,综合考虑不同生育期亏水水平处理下小麦地的经济效应和生态效应,T3处理更有利于关中平原冬小麦的保产节水减排.     

Simulation of Indian summer monsoon rainfall and its intraseasonal variability in the NCAR climate system model

The broad climatological features associated with the Asian monsoon circulation, including its mean state and intraseasonal and interannual variability over the Indian subcontinent as simulated in the National Center for Atmospheric Research (NCAR) global coupled climate system model (CSM) in its control reference experiment, are presented in this paper. The CSM reproduces the seasonal cycle as well as basic observed patterns of key climatic parameters reasonably well in spite of some limitations in simulation of the monsoon rainfall. However, while the seasonality in rainfall over the region is simulated well, the simulated area-averaged monsoon rainfall is underestimated to only about 60% of the observed rainfall. The centers of maxima in simulated monsoon rainfall are slightly displaced southward as compared to the climatological patterns. The cross-equatorial flow in simulated surface wind patterns during summer is also stronger than observed with an easterly bias. The transient experiment with a 1% per year compound increase in CO₂ with CSM suggests an annual mean area-averaged surface warming of about 1.73 °C over the region at the time of CO₂ doubling. This warming is more pronounced in winter than during the monsoon season. A net increase in area-averaged monsoon rainfall of about 1.4 mm day^–1, largely due to increased moisture convergence and associated convective activity over the land, is obtained. The enhanced intraseasonal variability in the monsoon rainfall in a warmer atmosphere is confined to the early part of the monsoon season which suggests the possibility of the date of onset of summer monsoon over India becoming more variable in future. The enhanced interannual and intraseasonal variability in the summer monsoon activity over India could also contribute to more intense rainfall spells over the land regions of the Indian subcontinent, thus increasing the probability of extreme rainfall events in a warmer atmosphere. Electronic Publication     

我国近10年城市生活垃圾处置单元温室气体排放时空变化及减排潜能分析

生活垃圾处置单元是重要的温室气体（GHG）排放源,明确其排放变化趋势及特征,是制定生活垃圾单元GHG减排的前提.采用IPCC清单模型,对中国2010~2020年城市生活垃圾（MSW）处置单元的GHG排放进行了估算.结果表明,GHG排放量（以CO₂-eq计,下同）从2010年的42.5 Mt增长至2019年的75.3 Mt,2020年降低到72.1 Mt;生活垃圾填埋场是GHG排放的主要来源,随着生活垃圾焚烧比例的增加,焚烧GHG排放占比从2010年的16.5%快速增加到2020年的60.1%;在区域分布上,华东和华南地区是排放量最高的区域,广东、山东、江苏和浙江是最主要的排放省.实行生活垃圾分类,转变生活垃圾处置方式（垃圾填埋向焚烧的转变）,提高填埋场填埋气体（LFG）收集效率,利用生物覆盖功能材料强化覆盖层甲烷（CH₄）氧化效率,是实现固废处置单元GHG减排的主要措施.     

2008~2017年中国地级市化肥施用碳足迹的时空演变格局

本研究收集整理近10年来我国地市年鉴化肥施用数据,基于生命周期分析思想定量研究我国2008~2017年地市尺度的化肥施用碳足迹时空演变特征.结果表明：2008~2017年,我国化肥施用碳足迹以2013年为节点呈现"先增大后减少"的单峰变化,2015年我国氮、磷和钾肥施用总碳足迹负荷为1.97t CO₂eq/hm²,较发达国家平均水平高出50%以上;在化肥生产和施用的全生命周期阶段,生产和运输过程的温室气体排放占比较高（60%以上）;氮肥的施用贡献了约91%的总化肥施用碳足迹;超过3/4的地市化肥施用碳足迹负荷过高,主要位于我国三大粮食主产区（华北平原,东北平原和长江中下游平原）;2013年以后仍有33个地市的化肥施用碳足迹依然保持增长,这些地区主要位于新疆,云南和黑龙江等地.本研究揭示了近10年我国化肥施用碳足迹的变化过程,可为我国绿色农业发展和温室气体相关政策制定提供一定参考依据.     

Environmental,economic and social costs and benefits of a packaging waste management system: A Portuguese case study

The impact of the management of packaging waste on the environment, economic growth and job creation is analyzed in this paper. This integrated assessment intends to cover a gap in the literature for this type of studies, using the specific case study of the Portuguese packaging waste management system (SIGRE).The net environmental benefits associated with the management of packaging waste, are calculated using the Life Cycle Assessment methodology. The results show that, for the categories studied, the impacts associated to SIGRE's various activities are surpassed by the benefits associated to material and energy recovery, with special focus on recycling. For example, in 2011 SIGRE avoided the emission of 116 kt CO₂ equiv. – the equivalent carbon emission of the electricity consumption of 124.000 households in Portugal.The economic impact of SIGRE is evaluated through Input–Output Analysis. It was found that SIGRE's activities also have a significant economic impact. For example, their added value are ranked amongst the upper third of the economic activities with highest multiplier effect at national level: this means that for each Euro of value added generated within SIGRE, 1.25 additional € are added to the rest of the economy (multiplier effect of 2.25).Regarding the social impacts of SIGRE, the number of direct jobs associated with the system is estimated to be more than two thousand and three hundred workers. Out of these, 83% are connected to the management of municipal waste packaging (selective collection and sorting), 15% are connected to the management of non-municipal packaging waste and only 2% are connected to the Sociedade Ponto Verde (SPV, green dot society in English) – the management entity responsible for SIGRE.In general terms, the results obtained provide quantitative support to the EEA (2011) suggestion that moving up the waste hierarchy – from landfilling to recycling – creates jobs and boosts the economy.