Bioethanol from waste: Life cycle estimation of the greenhouse gas saving potential

This paper considers two alternative feedstocks for bioethanol production, both derived from household waste—Refuse Derived Fuel (RDF) and Biodegradable Municipal Waste (BMW). Life Cycle Assessment (LCA) has been carried out to estimate the GHG emissions from bioethanol using these two feedstocks. An integrated waste management system has been considered, taking into account recycling of materials and production of bioethanol in a combined gasification/bio-catalytic process. For the functional unit defined as the ‘total amount of waste treated in the integrated waste management system’, the best option is to produce bioethanol from RDF—this saves up to 196 kg CO₂ equiv. per tonne of MSW, compared to the current waste management practice in the UK.However, if the functional unit is defined as ‘MJ of fuel equiv.’ and bioethanol is compared with petrol on an equivalent energy basis, the results show that bioethanol from RDF offers no saving of GHG emissions compared to petrol. For example, for a typical biogenic carbon content in RDF of around 60%, the life cycle GHG emissions from bioethanol are 87 g CO₂ equiv./MJ while for petrol they are 85 g CO₂ equiv./MJ. On the other hand, bioethanol from BMW offers a significant GHG saving potential over petrol. For a biogenic carbon content of 95%, the life cycle GHG emissions from bioethanol are 6.1 g CO₂ equiv./MJ which represents a saving of 92.5% compared to petrol. In comparison, bioethanol from UK wheat saves 28% of GHG while that from Brazilian sugar cane – the best performing bioethanol with respect to GHG emissions – saves 70%. If the biogenic carbon of the BMW feedstock exceeds 97%, the bioethanol system becomes a carbon sequester. For instance, if waste paper with the biogenic carbon content of almost 100% and a calorific value of 18 MJ/kg is converted into bioethanol, a saving of 107% compared to petrol could be achieved. Compared to paper recycling, converting waste paper into bioethanol saves 460 kg CO₂ equiv./t waste paper or eight times more than recycling.     

中国工业园区低碳发展路径研究

中国政府承诺CO₂排放力争于2030年前达到峰值,努力争取2060年前实现碳中和。在工业部门深化应对气候变化和全面推进绿色转型的背景下,数量庞大的工业园区已然成为"十四五"乃至今后一个时期工业领域实现科学、精准碳减排的关键靶点。本研究首先剖析了中国工业园区低碳发展面临的挑战与机遇;进而以2015年为基准年,面向2035和2050年美丽中国建设两阶段战略目标,研究提出了工业园区碳减排的目标、路径和潜力,以期为园区深化低碳发展提供决策参考。研究显示,2015年中国工业园区CO₂排放总量约为28亿吨,占全国总排放量的31%。通过产业结构调整、能效提升、能源结构优化、碳捕集等低碳路径,2015-2050年全国园区预期可减排CO₂ 18亿吨,在2015年基础上减排60%以上;其中,2015-2035年减排8亿吨,2035-2050年减排10亿吨。     

Energy balance and global warming potential of corn straw-based bioethanol in China from a life cycle perspective

As the second largest corn producer in this world, China has abundant corn straw resources. The study assessed the energy balance and global warming potential of corn straw-based bioethanol production and utilization in China from a life cycle perspective. The results revealed that bioethanol used as gasoline and diesel blend fuel could reduce global warming potential by 10%–97% and 4%–96%, respectively, as compared to gasoline and diesel for transport. The total global warming potential, net global warming potential, net energy, and Net Energy Ratio per MJ ethanol generated from corn straw-based bioethanol system are estimated to be 0.20 kg CO₂-eq, 0.012 kg CO₂-eq, 0.60 MJ, and 1.87, respectively. By using sensitivity analysis, we found that the collected coefficient and compressing density of straw have a more obvious influence on energy balance; transportation distance has a more obvious influence on global warming potential emission factor. The by-products may be utilized as fertilizer, animal feed, cement replacement, or high-value lignin chemicals, which make a contribution to offsetting 0.28 MJ per MJ ethanol of energy consumption.     

Analysis of emission characteristics of gas turbine engines with some alternative fuels

The paper concerns the comparative analysis of combustion characteristics of different alternative fuels such as Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), cryogenic methane, bioethanol, biomethanol, biobutanol, dimethyl ether, biodiesel and conventional aviation kerosene Jet-A as well as analysis of emissions of NO_x, CO, CO₂, H₂O, HNO_y (y = 2,3) and organics for gas turbine engine operating on these fuels. The analysis has shown that the usage of all considered alternative fuels results in the increase of H₂O emission, compared to kerosene-fueled combustor, and, as consequence, in the growth of water vapor supersaturation that can increase the rate of the H₂O vapor condensation and enhance the formation of contrails and cirrus clouds in the atmosphere. The usage of all considered alternative fuels except FT-SPK, cryogenic methane and dimethyl can increase the CO₂ emission compared to using of kerosene. Emission of N-containing species can be reduced upon the usage of considered alternative fuels, except dimethyl ether, for which one can expect the increase in the emissions of HNO₂ and HNO₃ approximately by 10%. The emission of CO decreases for all fuels except biodiesel. The major decrease can be achieved upon the replacement of kerosene to bioethanol.     

Feasibility of storing CO2 in the Utsira formation as part of a long term Dutch CCS strategy: An evaluation based on a GIS/MARKAL toolbox

This study provides insight into the feasibility of a CO₂ trunkline from the Netherlands to the Utsira formation in the Norwegian part of the North Sea, which is a large geological storage reservoir for CO₂. The feasibility is investigated in competition with CO₂ storage in onshore and near-offshore sinks in the Netherlands. Least-cost modelling with a MARKAL model in combination with ArcGIS was used to assess the cost-effectiveness of the trunkline as part of a Dutch greenhouse gas emission reduction strategy for the Dutch electricity sector and CO₂ intensive industry. The results show that under the condition that a CO₂ permit price increases from €25 per tCO₂ in 2010 to €60 per tCO₂ in 2030, and remains at this level up to 2050, CO₂ emissions in the Netherlands could reduce with 67% in 2050 compared to 1990, and investment in the Utsira trunkline may be cost-effective from 2020–2030 provided that Belgian and German CO₂ is transported and stored via the Netherlands as well. In this case, by 2050 more than 2.1 GtCO₂ would have been transported from the Netherlands to the Utsira formation. However, if the Utsira trunkline is not used for transportation of CO₂ from Belgium and Germany, it may become cost-effective 10 years later, and less than 1.3 GtCO₂ from the Netherlands would have been stored in the Utsira formation by 2050. On the short term, CO₂ storage in Dutch fields appears more cost-effective than in the Utsira formation, but as yet there are major uncertainties related to the timing and effective exploitation of the Dutch offshore storage opportunities.     

CO2 emissions in calcium carbide industry: An analysis of China's mitigation potential

China's calcium carbide output has dominated the global market for several years, driven by the demand for PVC (polyvinyl chloride), a fundamental polymer material and also the primary downstream product of calcium carbide in China. The fast growth of this energy-intensive industry leads to an inevitable increase in CO₂ emissions. However, there is a large reduction potential with process improvement in this industry which is currently characterized by widespread outdated facilities. In this study, we attempt to assess the reduction potential of CO₂ emissions in China's calcium carbide production, based on the analysis of CO₂ emission patterns and estimation of the emission amount. Three scenarios regarding process improvement are employed to conduct this assessment. The results imply that the cumulative CO₂ abatement in the Current Policy Scenario and in the Strengthened Policy Scenario from 2008 to 2020, compared with the Baseline Scenario, are 89.0 and 107.6 million t, respectively. The specific measures and policy implications to achieve this potential are also discussed in the article.     

Economic evaluation of the geological storage of CO2 considering the scale of economy

CO₂ capture and storage (CCS) technology is expected to play an important role in the efforts directed toward long-term CO₂ emission reduction. This paper analyzes the cost of the geological storage of CO₂ in Japan in order to consider future research, development and deployment (RD&D); these would be based on the information of the obtained cost structure. According to the analysis results, the costs, particularly those of the transportation by pipeline and of CO₂ injection, strongly depend on the scale of the facilities. Therefore, the distance of the transportation of CO₂ should be minimized in the case of small-scale storage, particularly in Japan. In addition, the potential injection rate per well is another key factor for the injection cost. Based on the analyzed cost, the injection cost of the geological storage of CO₂ in Japan for individual storage sites is estimated, and the cost–potential curve is obtained. A mixed-integer programming model has been developed to take into account these characteristics of the CCS technology and its adverse effects arising from the scale of economy with regard to the transportation and injection cost for the geological storage of CO₂. The model is designed to evaluate CCS and other CO₂ mitigation technologies in the energy systems of Japan. With all these adverse effects due to the scale of economy, the geological storage of CO₂ will be one of the important options for CO₂ emission reduction in Japan.     

中国城市碳达峰趋势的聚类分析

中国在2020年9月提出2060年碳中和目标,并提出加快落实2030年国家碳达峰任务。考虑到城市在国家碳减排工作中的重要使命和极大潜力,以及其碳排放在总量、结构、行动进展和趋势上存在的显著差异,深入认识中国城市碳达峰趋势的类型特征,对地方政府设计和开展差异化达峰行动具有重要意义。本文综合考虑影响城市碳达峰趋势的静态因素和动态因素,采用蒙特卡洛方法与K均值聚类算法,对中国286个样本城市的达峰趋势进行了分类分析。结果表明,中国城市的达峰类型可以划分为5类,根据其特点可概括为低碳潜力型城市、低碳示范型城市、人口流失型城市、资源依赖型城市和传统工业转型期城市。其中,低碳潜力型城市和传统工业转型期城市是决定我国能否落实2030年达峰行动的关键。最后,针对不同类型城市,本文对城市碳达峰的目标设计和行动重点提出了切实建议。     

The Climate Value of Cycling

The reduction of CO₂ emissions constitutes one of the largest challenges of the current era. Sustainable transportation, and especially cycling, can contribute to the mitigation of CO₂ emissions since cycling possesses an intrinsic zero‐emission value. Few studies have been conducted that appraise the CO₂ reduction potential of cycling. Opportunity costs enable the estimation of avoided CO₂ emissions resulting from bicycle trips. The methodology developed in this research allows the attribution of a climate value to cycling by substituting bicycle trips with their most likely alternative transportation modes and calculating the resulting additional CO₂ emissions. The methodology uses data on the current modal shares of cycling mobility, the competition of cycling with other transportation modes, and CO₂ emission factors to calculate the climate value of cycling. When it is assumed that the avoided CO₂ emissions of cycling mobility could be traded on financial carbon markets, the climate value of cycling represents a monetary value. Application of the methodology to the case of Bogotá, Colombia — a city with a current bicycle modal share of 3.3% on a total of 10 million daily trips — results in a climate value of cycling of 55,115 tons of CO₂ per year, corresponding to an economic value of between 1 and 7 million US dollars when traded on the carbon market.     

Modelling the economic consequences of the EU Water Framework Directive for Dutch agriculture

The EU Water Framework Directive (WFD) requires member states to take measures to ensure that bodies of water will be in good chemical and ecological condition by 2015. Important measures to achieve this goal include reducing emissions of nitrogen (N) and phosphate (P₂O₅) from manure and mineral fertilizers into the environment. In regions with a high livestock density, this measure is expected to affect agricultural production and income. To quantify these effects, an environmental economic model is required that can assess alternatives capable of reducing N and P₂O₅ potential emissions to water. In this paper, we develop a model that is capable of analysing changes in potential emissions to water of N and P₂O₅ and apply it to the Netherlands, a country with large nutrient emissions. Compared to a 2015 reference scenario based on current efforts to reduce nutrient emissions, we found that the WFD measures will increase regional transport and export of manure and reduce the number of animals in the Netherlands. Fodder adjustments (defined as lower N and P₂O₅ input in purchased fodder) to decrease nutrient excretion in manure were a less attractive option than amongst others export, transportation of manure to another region, land use changes or reduction of the number of livestock. Compared to the reference scenario in 2015, total agricultural income will decrease by about €81.5 million per year (about €49/ha per year), although the effects will differ among parts of the Netherlands and agricultural sectors. The average predicted decrease in N emissions from agricultural sites, vulnerable to leaching into bodies of water will be almost 20% or approximately 14.7 kg N/ha per year. The reduction in N emissions to air from animal sheds, manure storage systems, application of animal manure and mineral fertilisers to the crops and grazing animals equals 6.5% or 5 kg ammonia (NH₃) per hectare.     

Potential of solar domestic hot water systems in rural areas for greenhouse gas emission reduction in Poland

Application of solar energy for preparing domestic hot water is one of the easiest methods of utilization of this energy. At least part of the needs for warm tap water could be covered by solar systems. At present, mainly coal is used for water heating at dwellings in rural areas in Poland. Warm tap water consumption will increase significantly in the future as standards of living are improved. This can result in the growth of electricity use and an increase in primary fuel consumption. Present and future methods of warm sanitary water generation in rural areas in Poland is discussed, and associated greenhouse gas (GHG) emissions are estimated. It is predicted that the emission of CO₂ and NOx will increase. The emission of CO and CH₄ will decrease because of changes in the structure of the final energy carriers used. The economic and market potentials of solar energy for preparing warm water in rural areas are discussed. It is estimated that solar systems can meet 30%–45% of the energy demand for warm water generation in rural areas at a reasonable cost, with a corresponding CO₂ emission reduction. The rate of realization of the economic potential of solar water heaters depends on subsidies for the installation of equipment.

     

A model for the CO2 capture potential

Global warming is a result of increasing anthropogenic CO₂ emissions, and the consequences will be dramatic climate changes if no action is taken. One of the main global challenges in the years to come is therefore to reduce the CO₂ emissions.Increasing energy efficiency and a transition to renewable energy as the major energy source can reduce CO₂ emissions, but such measures can only lead to significant emission reductions in the long-term. Carbon capture and storage (CCS) is a promising technological option for reducing CO₂ emissions on a shorter time scale.A model to calculate the CO₂ capture potential has been developed, and it is estimated that 25 billion tonnes CO₂ can be captured and stored within the EU by 2050. Globally, 236 billion tonnes CO₂ can be captured and stored by 2050. The calculations indicate that wide implementation of CCS can reduce CO₂ emissions by 54% in the EU and 33% globally in 2050 compared to emission levels today.Such a reduction in emissions is not sufficient to stabilize the climate. Therefore, the strategy to achieve the necessary CO₂ emissions reductions must be a combination of (1) increasing energy efficiency, (2) switching from fossil fuel to renewable energy sources, and (3) wide implementation of CCS.     

Trace Gas Emissions from Biomass Burning from Northeast Region in India—Estimates from Satellite Remote Sensing Data and GIS

Biomass burning associated with shifting cultivation areas from the northeastern region of India is an important source of trace gas emissions in the Southeast Asian region. In the present study, satellite data pertaining to IRS-P4 OCM data and DMSP-OLS has been used to quantify the intensity, areal extent and amount of biomass burnt in the northeastern region states at district level. Trace gas emissions have been quantified both by using IPCC based emission ratios and ground based emission ratios obtained from field based studies. Areal estimates with respect to shifting cultivation areas from IRS-P4 OCM satellite data of 4th April 2000 suggested nearly 112.99 km² of the northeastern region of India affected due to shifting cultivation. In the study, DMSP OLS nighttime data has been used to capture the real time fires during the dry season. The results suggested high amount of fires during the March season when compared to April and May. Using the emission ratios obtained from the ground-based studies and IPCC emission ratios, the emissions for the individual non-CO₂ trace gases have been computed in a GIS framework using the biomass data, combustion factors and emission ratios. Results suggested emissions of 2.063 Mt CH₄, 17.94 Mt CO, 1.419 Mt N₂O, and 51.28 Mt NO _x and 2.643 Mt release of CH₄, 3.7204 Mt CO, 0.145 Mt N₂O, and 8.477 Mt NO _x , respectively, from biomass burning due to shifting cultivation for the year 2000, from the northeastern region in India. The study highlights the importance of Satellite Remote sensing data and GIS in quantifying the trace gas emissions from biomass burning.     

基于产业链分析的长三角地区CO2与大气污染物排放研究

长三角地区作为我国大气污染较为严重区域之一,如何在保持经济增长的同时减少CO₂与大气污染物的排放已成为一个重要挑战。本研究基于2007年与2012年长三角区域间投入产出表,定量分析了长三角地区省市间贸易引致的二氧化碳和大气污染物排放转移特征和变化趋势。同时,运用产业关联系数法,从前向关联与后向关联双重视角分析了长三角地区减缓CO₂和大气污染物排放的关键行业。研究结果表明,长三角的SO₂、PM_2.5排放总量表现为消费端大于生产端,CO₂、NO_x排放总量表现为生产端大于消费端。安徽省总体呈现为长三角地区贸易的SO₂、NO_x与PM_2.5排放净调出地,而上海与浙江表现为多数污染物排放净调入地。CO₂与大气污染物协同前向减排的关键行业为江苏省、浙江省和安徽省的电力、热力的生产和供应业,安徽省的煤炭开采和洗选业等,可以通过生产端技术革新和能源结构优化来促进减排;CO₂与大气污染物后向协同减排的关键行业为江苏省、浙江省和安徽省的建筑业等,对于这些行业,调整消费结构是有效的减排措施。为更好地制定长三角地区减排与污染防治政策,应当综合考虑行业减排、协同减排等,以确保经济持续增长的同时达到减排目标。     

城市蓝天保卫战行动协同控制局地大气污染物和温室气体效果评估——以唐山市为例

为满足在城市层面开展蓝天保卫战行动、协同控制局地大气污染物和温室气体效果评估的管理需求,本文构建了评估方法体系,明确了评估流程,并梳理了评估参数获取途径。本文所推荐的协同减排量核算方法和协同控制效果评估方法包括:采用排放因子法计算各措施的单项大气污染物和单项温室气体减排量,计算各措施的局地大气污染物当量(LAPeq)和二氧化碳当量(CO_2-eq)减排效果,进而采用协同控制效应坐标系分析和协同控制交叉弹性分析开展协同控制效果评估。本文以唐山市2018年蓝天保卫战行动为案例,选择12项子措施开展试点评估,结果显示:这12项子措施在减排LAPeq 13 840.89 t/a的同时,可协同减排温室气体1 009.43万t CO_2-eq/a;所评估的措施均位于协同控制效应坐标系第一象限;协同控制交叉弹性Els CO2-eq/LAPeq为6.66,即每减排1个百分点的LAPeq,可协同减排6.66个百分点的温室气体。研究表明,本文所提出的评估方法体系具有较好的适用性,可推广应用于城市蓝天保卫战行动协同控制局地大气污染物和温室气体评估工作中。     

Alternative energy balances for Bulgaria to mitigate climate change

Alternative energy balances aimed to mitigate greenhouse gas (GHG) emissions are developed as alternatives to the baseline energy balance. The section of mitigation options is based on the results of the GHG emission inventory for the 1987–1992 period. The energy sector is the main contributor to the total CO₂ emissions of Bulgaria. Stationary combustion for heat and electricity production as well as direct end-use combustion amounts to 80% of the total emissions. The parts of the energy network that could have the biggest influence on GHG emission reduction are identified. The potential effects of the following mitigation measures are discussed: rehabilitation of the combustion facilities currently in operation; repowering to natural gas; reduction of losses in thermal and electrical transmission and distribution networks; penetration of new combustion technologies; tariff structure improvement; renewable sources for electricity and heat production; wasteheat utilization; and supply of households with natural gas to substitute for electricity in space heating and cooking. The total available and the achievable potentials are estimated and the implementation barriers are discussed.

     

基于混合生命周期评价模型的我国食物系统水资源消耗及二氧化碳排放核算

食物生产不仅依赖水资源,同时产生大量二氧化碳排放,这种资源环境影响存在于食物系统整个产业链。为促进食物系统节水降碳,本文构建了包含5大类共23种具体食物部门的混合生命周期评价模型,对各类食物系统的完全水资源消耗和二氧化碳排放进行了核算与比较。结果表明：(1)不同食物的水资源消耗和二氧化碳排放差异明显,动物性食物的平均水资源消耗和二氧化碳排放强度分别为植物性食物的1.9～15.0倍和1.9～2.7倍;(2)食物系统直接和间接水资源消耗占比较为接近,但二氧化碳排放主要源自上游产业链的间接排放,占比高达80.9%;(3)食物系统间接水资源消耗主要来自农业部门,而间接碳排放主要来自电力生产和供应业、基础化工原料制造业、非金属矿产品行业和交通运输业;(4)从营养元素供给看,动物性食物提供蛋白质和脂肪的资源环境影响高于植物性食物,蔬菜和主食分别在提供维生素C和碳水化合物上具有最小的环境成本。基于本文结果,食物系统节水应主要提高生产环节用水效率,而降碳则主要依靠上游产业减排,特别是发电和化肥生产等行业的协同节水减碳潜力。同时,本文结果也可为未来基于环境影响制定膳食指南提供数据支撑。     

Environmental impacts of absorption-based CO2 capture unit for post-combustion treatment of flue gas from coal-fired power plant

This study assesses potential environmental impacts of the absorption-based carbon dioxide (CO₂) capture unit that is integrated to coal-fired power plant for post-combustion treatment of flue gas. The assessment was performed by identifying potential pollutants and their sources as well as amounts of emissions from the CO₂ capture unit and also by reviewing toxicology, potential implications to human health and the environment, as well as the environmental laws and regulations associated with such pollutants. The assessment shows that, while offering a significant environmental benefit through a reduction of greenhouse gas emissions, the installation of CO₂ capture units for post-combustion treatment might induce unintentional and potential burdens to human health and the environment through four emission pathways, including treated gas, process wastes, fugitive emissions, and accidental releases. Such burdens nevertheless can be predetermined and properly mitigated through a well-established environmental management program and mitigation measures. Recommendations to minimize these impacts are provided in this paper.