沼气发酵猪粪管理系统对温室气体排放的影响

基于生命周期清单分析以及清洁发展机制,引入"碳足迹"概念,对我国散养猪以及规模化养猪场引入沼气发酵系统后猪粪管理系统温室气体排放及减排进行了估算。农户散养猪粪处理系统中,12 m3沼气池厌氧发酵过程碳足迹为223.40 kg CO2e/a,沼气代替原煤燃烧减少444.33 kg CO2e/a温室气体,沼气发酵净减少220.93 kg CO2e/a温室气体,我国散养生猪产生的猪粪以此沼气池发酵可减少温室气体20 984.62 Gg CO2e/a;分析运行规模约1 000 m3大型沼气工程的碳足迹,保守估计为2 835.32 t CO2e/a,运行沼气工程替代煤炭以及减少猪粪排放的温室气体共约2 914.23 t CO2e/a,故沼气工程年减少温室气体78.91 t CO2e,该项目共可减排1 578.20 t CO2e。在猪粪管理系统中采用沼气发酵系统可以更好地促进温室气体减排的进行。     

Energy requirements of consumption: Urban form,climatic and socio-economic factors,rebounds and their policy implications

Household consumption requires energy to be used at all stages of the economic process, thereby directly and indirectly leading to environmental impacts across the entire production chain. The levels, structure and determinants of energy requirements of household consumption therefore constitute an important avenue of research. Incorporating the full upstream requirements into the analysis helps to avoid simplistic conclusions which would actually only imply shifts between consumption categories without taking the economy wide effects into account. This paper presents the investigation of the direct and indirect primary energy requirements of Australian households, contrasting urban, suburban and rural consumption patterns as well as inter- and intra-regional levels of inequality in energy requirements. Furthermore the spatial and socio-economic drivers of energy consumption for different categories of energy requirements are identified and quantified. Conclusions regarding the relationships between energy requirements, household characteristics, urban form and urbanization processes are drawn and the respective policy implications are explored.     

Financial and Ecological Evaluation of Hydrogen Production Processes on Large Scale

Hydrogen is widely seen as energy carrier of the future. Different technologies are under development to produce hydrogen at competitive cost but with significantly reduced carbon footprint. Two conventional technologies, namely, methane steam reforming and coal gasification, are compared based on product cost and carbon footprint with four new technologies, i.e., metal‐oxide cycle, water electrolysis, biomass gasification, and methane pyrolysis. To evaluate the carbon footprint for methane pyrolysis, system extension and differential methods are applied. For the boundary conditions selected here, methane pyrolysis yields very good values for product cost and carbon footprint. Therefore, a cross industry technology development of methane pyrolysis was initiated.     

Influence of anaerobic digestion on the carbon footprint of various sewage sludge treatment options

This paper describes the results of a model set up to determine carbon footprints for sludge treatment solutions with and without standard or advanced anaerobic digestion. Complete and 'gate' (up to the point the sludge leaves the sewage works gate) footprints were calculated. The lowest carbon footprints corresponded with advanced digestion options, which reduced downstream energy and transport (hence carbon) requirements regardless of the endpoint of the sludge. The lowest complete carbon footprint solution coincided with advanced digestion, followed by drying with energy recovery. However, this option had the highest gate carbon footprint. In terms of gate carbon footprint, land application of an advanced digested sludge cake had the smallest footprint, followed by land application of dried pellets and finally incineration.     

中国水库温室气体研究(2009-2019):回顾与展望

筑坝蓄水将显著改变陆地水系统碳循环,衍生的水库CO_2、CH_4等温室气体源汇变化问题近年来备受国际关注。近30年来,该领域研究已从早期的质疑、争议逐渐拓展深化,并在一定范围内取得学术共识。2009年,Nature引用中国学者的研究成果表达了对三峡水库温室气体源汇变化的担忧。该事件成为具有标志意义的重要起点,开启了此后10年中国在该领域研究的重要发展期。以三峡水库为代表的中国大中型水库多具有典型的河道型特征,淹没面积少,能量密度普遍较高,但相关研究成果仍十分有限。本文报道了近10年来三峡水库CO_2、CH_4源汇变化监测评估结果。以2010年为参考年,在不考虑防洪、航运等其他效益的情形下,扣减蓄水前水库淹没区与自然河道的CO_2、CH_4释放通量后,三峡水库2010年因发电产生的碳排放量约为13.2 g(CO_2eq)·(kW·h)~(-1),低碳属性明显。2019年,在中国学者参与努力下,政府间气候变化专门委员会(IPCC)通过并正式颁布了水淹地国家温室气体清单精细化修编。这对客观、公正地衡量水库温室气体源汇变化具有重要的学术意义。未来该领域将更聚焦河流-水库系统碳氮生态水文过程与地球化学机制,也将在更宏观的视角下考察水电能源全生命周期碳足迹。建议我国进一步强化该领域基础研究,推进水电碳足迹评价的标准化,引导水电行业重视碳资产管理,探索减源增汇方法与途径。     

基于生态足迹法的镇赉县生态环境现状评价

吉林省镇赉县位于我国北方农牧交错带,作为一个国家商品粮基地,农业发展的比重大。为了探讨镇赉县生态环境现状和资源消耗特点以及农牧交错带在承担外来资源压力转移方面的作用,应用生态足迹法对镇赉县2010年生物资源生产数据和能源消费数据进行了分析,结果表明镇赉县农牧业发展在资源利用中占主要地位,农牧业生产中大部分产品用于对外销售,因此该地区承担了巨大的外来资源压力转移,已经出现生态赤字。进一步分析还发现,为推动农业发展,当地通过扩大耕地面积来解决粮食产量低、无复种的问题,因此占用其他土地类型,这些活动过度干扰了生态环境,加剧了镇赉县生态环境的恶化。     

低碳混凝土的技术理念与途径思考

从全球碳中和与可持续混凝土发展角度阐述了低碳混凝土的基本概念及全生命周期的减碳与碳汇核心技术理念.从原材料、混凝土设计、制备、施工、服役及再生利用等全生命周期过程提出了低碳混凝土的三大技术途径——直接减碳、间接减碳及碳汇技术,并分析了每个技术途径下的具体减碳技术路线.综述了混凝土的碳排放评价方法和准则,阐释了混凝土碳排放的生命周期评价方法 .提出了低碳混凝土未来的重点研究方向——开发新型胶凝材料以及碳汇技术.     

Combined Decarbonization of Electrical Energy Generation and Production of Synthetic Fuels by Renewable Energies and Fossil Fuels

Power generation from renewable energy sources and fossil fuels are integrated into one system. A combination of technologies in the form of a carbon capture utilization (CCU)-combined power station is proposed. The technology is based on energy generation from fossil fuels by a coal power plant with CO₂ recovery from exhaust gases, and pyrolysis of natural gas to hydrogen and carbon, completed by reverse water-gas shift for the conversion of CO₂ to CO, which will react with hydrogen in a Fischer-Tropsch synthesis for synthetic diesel. The carbon from the pyrolysis can replace other fossil carbon or can be sequestered. This technology offers significant CO₂ savings compared to the current state of technology and makes an environmentally friendly use of fossil fuels for electricity and fuel sectors possible.     

Harmonised life-cycle indicators of nuclear-based hydrogen

When comparing the life-cycle environmental performance of hydrogen energy systems, significant concerns arise due to potential methodological inconsistencies between case studies. In this regard, protocols for harmonised life cycle assessment (LCA) of hydrogen energy systems are currently available to mitigate these concerns. These protocols have already been applied to conventional hydrogen from steam methane reforming as well as to a large number of both fossil and renewable hydrogen options, allowing robust comparisons between them. However, harmonised life-cycle indicators of nuclear-based hydrogen options are not yet available in the literature. This study fills this gap by using the recently developed software GreenH₂armony® to calculate the harmonised carbon, energy and acidification footprints of nuclear-based hydrogen produced through different pathways (viz., low-temperature electrolysis, high-temperature electrolysis, and thermochemical cycles). Overall, the harmonised case studies of nuclear-based hydrogen show a generally good performance in terms of carbon footprint and acidification, but an unfavourable performance in terms of non-renewable energy footprint.