Purchasings contribution to supply chain emission reduction
سهم خرید در کاهش انتشار زنجیره تامین-2021
Does environmental purchasing and supplier management (EPSM) help to reduce greenhouse gas (GHG) emissions in the supply chain and, thereby, mitigate climate change? And, if so, under which conditions? Taking these two questions as a starting point, we hypothesize that heightened environmental protection efforts targeting the upstream value chain should lead to a reduction of greenhouse gas emissions in the buying companies’ supply chain. We continue to delineate three contingency factors that might affect the relationship between EPSM and supply chain GHG emissions: The power of the buying firm over supply chain partners, prior experience in EPSM, and materiality of environmental supply chain management in a certain industry. We collect longitudinal data from 260 companies and analyze them using hybrid panel data analysis. We find that the increase of EPSM leads to a significant reduction of the GHG emission intensity of buying firms’ supply chains and that this reduction is stronger for companies operating in industries where emission management is more material.
Keywords: Sustainable supply chain management | Environmental purchasing | Environmental performance | Emission reduction | Climate change mitigation | Hybrid modelling
A more complete accounting of greenhouse gas emissions and sequestration in urban landscapes
یک حسابداری کاملتر از انتشار گازهای گلخانه ای و ترسیب در مناظر شهری-2021
Understanding interactions between complex human and natural systems involved in urban carbon cycling is important when balancing the dual goals of urban development to accommodate a growing population, while also achieving urban carbon neutrality. This study develops a systems breakdown accounting method to assess the urban carbon cycle. The method facilitates greater understanding of the complex interactions within and between systems involved in this cycle, in order to identify ways in which humans can adapt their interactions to reduce net greenhouse gas emissions from urban regions. Testing the systems breakdown accounting method in Stockholm County, Sweden, we find that it provides new insights into the carbon interactions with urban green-blue areas in the region. Results show how Stockholm County can reduce its emissions and achieve its goal of local carbon net-neutrality, if the green areas protect its carbon sequestration potential and maintain it to offset projected remaining active emissions. Results also show that the inland surface waters and inner archipelago waters within Stockholm County are a considerable source of greenhouse gases to the atmosphere. A better understanding of these water emissions is necessary to formulate effective planning and policy measures that can reduce urban emissions. The insights gained from this study can also be applied in other regions. In particular, water bodies could play a significant role in the urban carbon cycle and using this knowledge for more complete carbon accounting, and a better understanding of green-blue interactions could help to reduce net urban emissions in many places.
keywords: انتشار گازهای گلخانه ای | جداسازی کربن | چرخه کربن شهری | تغییر استفاده از زمین | برنامه ریزی شهری پایدار | حسابداری کربن | Greenhouse gas emissions | Carbon sequestration | Urban carbon cycle | Land use change | Sustainable urban planning | Carbon accounting
Bi-objective optimal design of hydrogen and methane supply chains based on Power-to-Gas systems
طراحی بهینه دو هدفه زنجیره های تأمین هیدروژن و متان بر اساس سیستم های نیرو به گاز-2021
This paper presents a methodological design framework for Hydrogen and Methane Supply Chains (HMSC) based on Power-to-Gas (PtG) systems. The novelty of the work is twofold, first considering a specific demand for hydrogen for electromobility in addition to the hydrogen demand required as a feedstock to produce synthetic methane from the methanation process. and performing a bi-objective optimization of the HMSC to provide effective support for the study of deployment scenarios. The approach is based on a Mixed Integer Linear Programming (MILP) approach with augmented epsilon-constraint implemented in the GAMS environment according to a multi-period approach (2035-2050) with several available energy sources (wind, PV, hydro, national network) for hydrogen production. Carbon dioxide sources stem mainly from mechanization and gasification processes. The objectives to be minimized simultaneously are the Total Annual Cost and the greenhouse gas emissions related to the whole HMSC over the entire period studied.
KEYWORDS: Power-to-Gas | Methanation | Hydrogen | MILP | Augmented epsilon constraint | GAMS | optimization approach
Greenhouse gas emissions in British Columbia: Production versus consumption accounting from 2010 to 2015
انتشار گازهای گلخانه ای در بریتیش کلمبیا: تولید در مقایسه با مصرف حسابداری از سال 2010 تا 2015-2021
As a result of carbon-pricing policies, a number of jurisdictions across the world claim to be decoupling their greenhouse gas (GHG) emissions from their gross domestic product (GDP). In British Columbia (BC), Canada, in what appears to be decoupling from 2007 to 2018, GHGs with respect to GDP declined by 16% ( BC Government 2020 ). This ﬁnding, however, is the result of a production-based method of accounting— the predominant global approach for allocating emissions—and not a consumption-based method. In this study, we compare these two accounting methods with respect to British Columbian decoupling. We cal- culate consumption-based emissions through a multi-regional input-output analysis from 2010 to 2015. In our results for 2015, we ﬁnd total consumption emissions of 82.5Mt of CO 2 e; when compared to the total production emissions of 73.7Mt of CO 2 e, we ﬁnd BC to be a net consumer of emissions by 8.8Mt of CO 2 e for 2015. Although BC has had this net consumer status since at least 2004 ( Dobson and Fellows, 2017 ), this orientation is in decline primarily due to the decarbonizing trends of China and the USA. In short, for BC from 2010–2015, on a per capita basis, both production and consumption accounts of emissions de- clined (even as GDP rose), but per capita consumption accounts declined more than production accounts and mostly due to emissions reductions from trade partners. Finally, this study may be of interest to policymakers and scientists, and like other scholars, we recommend that consumption-based inventories accompany production-based accounts when designing and assessing global GHG mitigation policy. © 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
keywords: انتشار گازهای گلخانه ای | تجزیه و تحلیل خروجی چند منطقه ای | معامله بین المللی | گازهای گلخانه ای | تغییرات اقلیمی | Embodied emissions | Multi-regional input-output analysis | International trade | Greenhouse gasses | Climate change
A methodological design framework for hydrogen and methane supply chain with special focus on Power-to-Gas systems: application to Occitania region, France
یک چارچوب طراحی روش برای زنجیره تأمین هیدروژن و متان با تمرکز ویژه بر روی سیستم های نیرو به گاز: کاربرد در منطقه اوکسیتانیا ، فرانسه-2021
This work presents a methodological design framework for Hydrogen and Methane Supply Chains (HMSC). An innovative approach is to focus on Power-to-Hydrogen (PtH) and Power-to-Methane (PtM) concepts, and their interactions with other technologies, and energy carriers (i.e., Steam Methane Reforming – SMR, and natural gas). The overall objective of this work is to perform single objective and multi-objective optimizations for HMSC design to provide effective support for deployment scenarios. The methodological framework developed is based on a Mixed Integer Linear Programming (MILP) approach with augmented ε-constraint implemented in the GAMS environment according to a multi-period approach (2035-2050). Several available energy sources (wind, PV, hydro, national power grid, and natural gas) for hydrogen production through electrolysis and SMR are included. Carbon dioxide sources stem mainly from methanization and gasification processes, which are used to produce methane through methanation. The objective to be minimised in the single optimization approach is the total annual cost considering the externality of greenhouse gas emissions through the carbon price for the whole HMSC over the entire period studied. The multi-objective optimization includes as objectives the total annual cost, greenhouse gas emissions, and the total methane production from methanation. The Levelized Cost of Energy (LCOE), and the greenhouse gas emissions for each energy carrier are also computed. The results show that renewable hydrogen from PtG can be competitive with SMR through the implementation of carbon prices below 0.27 €/kgCO2. In the case of synthetic methane, the available resources can meet the demand through PtG, and even if synthetic methane for natural gas network injection is thus far from competitive with natural gas, power-to-gas technologies have the potential to decarbonize the fossil economy and achieve a circular economy through CO2 recovery.
KEYWORDS: Power-to-Gas | Methanation | Hydrogen | MILP | supply chain | optimization
Impact of fuel-efficient technology on automotive and fuel supply chain under government intervention: A case study
تأثیر فناوری کم مصرف بر روی زنجیره تأمین سوخت و خودرو تحت مداخله دولت: مطالعه موردی-2021
Transportation is one of the most influential factors in greenhouse gas emissions and global warming. This paper studies a network with an automotive supply chain that includes one supplier and one manufacturer next to a fuel supply chain consisting of a fuel manufacturer, operating under government intervention. The car manufacturer sells its green and non-green products under the dual-channel system with stochastic demand and demand leakage. To decrease greenhouse gas emissions, the car manufacturer invests in fuel-efficient technology for green products to reduce car fuel consumption. Moreover, due to increasing public awareness of environmental issues, the supplier invests in greening efforts to provide raw materials for fuel-efficient cars. The fuel manufacturer determines the fuel price under the government supervision and the government considers subsidies to support it. The fuel manufacturer has the opportunity to export the surplus fuel to other markets at a higher price. The government supports the production of fuel-efficient cars with two policies of subsidy-taxation and granting loans to customers. By doing so, the car manufacturer improves the level of fuel-efficient technology and the greening efforts of the supplier are increased. Additionally, the amount of fuel consumption in the internal market is reduced and the fuel manufacturer can export more fuel to the external market. As a result, the profit of all members increases simultaneously and environmental conditions improve. This model is studied under two scenarios for the distribution function of stochastic part of demand: (1) the Stackelberg scenario with complete information as a uniform distribution function and (2) the Nash scenario with partial information on a distribution-free approach. Some numerical examples based on real cases are provided to examine the capability of the proposed models. Finally, some sensitivity analyses are applied to the main parameters to extract several in-depth managerial concepts.
Keywords: Automotive supply chain | Fuel-efficient car | Greening efforts | Government intervention | Technology level | Distribution-free approach
Techno-economic and life cycle greenhouse gas emissions assessment of liquefied natural gas supply chain in China
ارزیابی فنی و اقتصادی و چرخه زندگی انتشار گازهای گلخانه ای از زنجیره تامین گاز طبیعی مایع در چین-2021
This study assessed the techno-economic performance and life cycle greenhouse gas (GHG) emissions for various liqueﬁed natural gas (LNG) supply chains in China in order to ﬁnd the most efﬁcient way to supply and use LNG. This study improves current literature by adding supply chain optimization options (cold energy recovery and hydrogen production) and by analyzing the entire supply chain of four different LNG end-users (power generation, industrial heating, residential heating, and truck usage). This resulted in 33 LNG pathways for which the energy efﬁciency, life cycle GHG emissions, and life cycle costs were determined by process-based material and energy ﬂow analysis, life cycle assessment, and pro- duction cost calculation, respectively. The LNG and hydrogen supply chains were compared with a reference chain (coal or diesel) to determine avoided GHG emissions and GHG avoidance costs. Results show that NG with full cryogenic carbon dioxide capture (FCCC) is most beneﬁcial pathway for both avoided GHG emissions and GHG avoidance costs (70.5e112.4 g CO2-e/MJLNG and 66.0e95.9 $/t CO2-e). The best case was obtained when NG with FCCC replaces coal-ﬁred power plants. Results also indicate that hydrogen pathways requires maturation of new technology options and signiﬁcant capital cost reductions to become attractive.© 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/4.0/).
Keywords: Liquefied natural gas | Techno-economic assessment | Life cycle greenhouse gas emission | Cold recovery | Blue hydrogen
Evaluating CO2 emissions from continuous flow and batch growth systems under autotrophic mode: Implications for GHG accounting of biological nutrient removal
ارزیابی انتشار CO2 از جریان مداوم جریان و سیستم های رشد دسته ای تحت حالت اتوتروفیک: پیامدهای حسابداری GHG از حذف مواد مغذی زیستی-2021
The oxidation of ammonia by autotrophic bacteria is a central part of the nitrogen cycle and a fundamental aspect of biological nutrient removal (BNR) during wastewater treatment. Autotrophic ammonia oxidation produces protons and results in net-CO2 production due to the neutralizing effect of bicarbonate alkalinity. Attention must be paid to the propensity for this produced CO2 to be transferred to the atmosphere where it can act as a greenhouse gas (GHG). In the context of BNR systems, bicarbonate-derived CO2 emissions should be considered distinct from the biogenic CO2 that arises from cellular respiration, though this distinction is not made in current GHG accounting practices. The aim of this study was to evaluate the performance of two experimental systems operated under autotrophic mode and buffered with bicarbonate, to investigate the rela- tionship between ammonia removal and gaseous CO2 emissions. The first system consisted of continuously aerated lab-scale batch reactors, which were effective in demonstrating the important link between ammonia oxidizer activity, pH, and gaseous CO2 production. Depletion of the buffer system always led to a rapid decline in system pH and cessation of CO2 emissions when the pH fell below 7.0. The second system was a tubular continuous-flow biofilm reactor which permitted comparison of ammonia removal and CO2 emission rates. A linear relationship between ammonia removal and CO2 emissions was demonstrated and the quantified CO2 production was relatively close to that which was predicted based on the stoichiometry of nitrification, with this CO2 being detected in the gas phase. It was apparent that this system offered minimal resistance to the mass transfer of CO2 from the liquid to gas, which is an important factor that determines how much of the bicarbonate- derived CO2 may contribute to greenhouse gas emissions in engineered systems such as those used for BNR.
keywords: اکسیداسیون آمونیاک اتوتروفیک | بیوفیلم های autotrophic | حذف مواد مغذی زیستی | قلیایی کربنات | انتشار گاز CO2 | انتشار گازهای گلخانه ای | Autotrophic ammonia oxidation | Autotrophic biofilms | Biological nutrient removal | Carbonate alkalinity | CO2 emissions | Greenhouse gas emissions
Day-ahead energy management and feeder reconfiguration for microgrids with CCHP and energy storage systems
مدیریت انرژی روز و تنظیم مجدد فیدر برای میکروگرید با CCHP و سیستمهای ذخیره انرژی-2020
Energy management featuring distribution feeder reconfiguration (DFR) and reactive power control, improves the technical and economic efficiency of microgrids. The present work proposes a framework that leverages scenarios to jointly manage the real and reactive power dispatches of the controllable generation resources as well as the topology of the distribution feeder. Multiple operation measures are optimized including the operation cost, real power loss, the voltage stability index (VSI), and the greenhouse gas emissions of the microgrid. Hybrid Big Bang- Big Crunch (HBB-BC) algorithm is used to solve the formulated optimization problem. Nondispatchable and dispatchable distributed generation units (DGs), as well as the battery and thermal energy storage systems (BESS and TESS), are considered as a hybrid energy system. Combined cooling, heating, and power (CCHP) units are considered as dispatchable DGs and wind and solar photovoltaic generations are considered as non-dispatchable DGs. The efficiency of the proposed model and solution algorithm is investigated using a 33-bus microgrid, and the simulation outcomes are discussed.
Keywords: Combined cooling, heating, and power (CCHP) | Distribution feeder reconfiguration (DFR) | Distributed generation (DG) | Energy storage system (ESS)
Prediction of greenhouse gas emissions from Ontario’s solid waste landfills using fuzzy logic based model
پیش بینی انتشار گازهای گلخانه ای از محل های دفع زباله جامد انتاریو با استفاده از مدل مبتنی بر منطق فازی-2020
In this study, multi-criteria assessment technique is used to predict the methane generation from large municipal solid waste landfills in Ontario, Canada. Although a number of properties determine the gas generation from landfills, these parameters are linked with empirical relationships making it difficult to generate precise information concerning gas production. Moreover, available landfill data involve sources of uncertainty and are mostly insufficient. To fully characterize the chemistry of reaction and predict gas generation volumes from landfills, a fuzzy-based model is proposed having seven input parameters. Parameters were identified in a linguistic form and linked by 19 IF-THEN statements. When compared to measured values, results of the fuzzy based model showed good prediction of landfill gas generation rates. Also, when compared to other first order decay and second order decay models like LandGEM, the fuzzy based model showed better results. When plotting the LandGEM and Fuzzy model values to the actual measured data, the fuzzy model resulted in a better fit to actual data than the LandGEM model with a coefficient of determination R2 of 0.951 for fuzzy model versus 0.804 for LandGEM model. The results show how multi-criteria assessment technique can be used in modelling of complicated processes that take place within the landfills and somehow accurately predicting the landfill gas generation rate under different operating conditions
Keywords: Municipal solid waste | Landfill gas | Life-cycle assessment | Waste to energy | Greenhouse gas emissions | Fuzzy model