Hybrid Life Cycle Assessment Approach Research Articles

Sustainability assessment of peri-urban organic horticulture — A case study in the United Kingdom

PurposeThere is a growing concern about the resilience and sustainability of horticultural production in the United Kingdom (UK) as a result of high energy costs and insufficient local labour, causing over-reliance on imports. In this study, we present an integrated environmental and economic assessment of organic peri-urban horticulture using primary data from a farm in Sheffield.MethodsThis study includes a farm-to-gate hybrid life cycle assessment (LCA) using the ReCIPE (H) approach for the functional unit of 1-kg tomatoes produced in an unheated polytunnel without supplementary lighting, and 1 kg of field-grown courgettes. All analyses were conducted in SimaPro software using environmental data from the ecoinvent database. Results were compared with those from a systematic literature review of similar studies.ResultsWe found that the production of organic tomatoes and courgettes resulted in a global warming potential (GWP) of 0.61 kg CO2-eq and 0.11 kg CO2-eq respectively using a process-based LCA approach. Using a hybrid LCA approach, however, yielded a GWP of 3.53 kg CO2-eq and 1.70 kg CO2-eq for the production of organic tomatoes and courgettes respectively. An additional scenario included farmgate-to-warehouse transportation for both domestic and imported produce from Spain, but found that the GWP of tomatoes in the case study was 1.87 times higher than those from Spain. Economic analysis showed that the marginal increase in the prices of tomatoes and courgettes from the case study farm was 4.6 and 5.15 times less than the market prices.ConclusionWe conclude that the studied production system is both economically and environmentally sustainable as compared to the existing scenario. Other potential benefits of peri-urban organic horticulture include employment, mental health, community cohesion, which remain to be explored in a future qualitative study. The present study is novel as it appears to be the first application of hybrid LCA to UK horticulture. The findings are highly topical given the recent horticultural supply constraints in the UK.

A Novel Hybrid Life Cycle Assessment Approach to Air Emissions and Human Health Impacts of Liquefied Natural Gas Supply Chain

Global interest in LNG products and supply chains is growing, and demand continues to rise. As a clean energy source, LNG can nevertheless emit air pollutants, albeit at a lower level than transitional energy sources. An LNG plant capable of producing up to 126 MMTA was successfully developed and simulated in this study. A hybrid life cycle assessment model was developed to examine the social and human health impacts of the LNG supply chain’s environmental air emission formation. The Multiregional Input–Output (MRIO) database, the Aspen HYSYS model, and the LNG Maritime Transportation Emission Quantification Tool are the key sources of information for this extensive novel study. We began our research by grouping environmental emissions sources according to the participation of each stage in the supply chain. The MDEA Sweetening plant, LNG loading (export terminal), and LNG transportation stages were discovered to have the maximum air emissions. The midpoint air emissions data estimated each stage’s CO2-eq, NOx-eq, and PM2.5-eq emissions per unit LNG generated. According to the midpoint analysis results, the LNG loading terminal has the most considerable normalized CO2-eq and NOx-eq emission contribution across all LNG supply chain stages. Furthermore, the most incredible intensity value for normalized PM2.5-eq was recorded in the SRU and TGTU units. Following the midpoint results, the social human health impact findings were calculated using ReCiPe 2016 characterization factors to quantify the daily loss of life associated with the LNG process chain. SRU and TGTU units have the most significant social human health impact, followed by LNG loading (export terminal) with about 7409.0 and 1203.9 (DALY/million Ton LNG produced annually), respectively. Natural gas extraction and NGL recovery and fractionation units are the lowest for social human health consequences.

Estimating carbon emissions from road use, maintenance and rehabilitation through a hybrid life cycle assessment approach – A case study

Road infrastructure is an important source of carbon emissions. To estimate the carbon emissions of roads, life cycle assessment (LCA) methods are widely used. Due to budget constraints, road maintenance and rehabilitation (M&R) is preferred by road agencies over new construction. However, existing LCA studies on roads have limited considerations on the emissions from the use and M&R phases. This study aims to propose and illustrate a structured hybrid LCA approach that can be adopted by road agencies to evaluate carbon emissions of the use and M&R phases of roads. A path exchange LCA method and a tiered hybrid LCA method are integrated in the proposed approach. To illustrate the proposed approach, a case study of a road network in Western Australia is conducted, which includes 17,764 road segments. The results show that from 2017 to 2026, the GWP of use and M&R phases is increased from 467.8 t CO2-e/km to 589.5 t CO2-e/km·with an increasing trend. The use phase has much higher global warming potential than the M&R phase during the service life of roads. The results are the most sensitive to annual average daily traffic (AADT). In addition, heavy traffic roads in the metropolitan area and freeways with AADT higher than 20,000 are identified to be the most carbon intensive. The proposed approach is believed to have better accuracy when compared to a process-based approach and a tiered approach, which provide the results of 128.6–164.4 t CO2-e/km and 468.0–608.9 t CO2-e/km, respectively. The results can provide implications for road authorities to evaluate their priorities when allocating limited M&R funds to achieve sustainable objectives.

Utilizing off-the-shelf LCA methods to develop a ‘triple bottom line’ auditing tool for global cataract surgical services

Cataract surgery is the most commonly performed medical procedure in the world but there continues to be a large, unmet requirement for more surgery, with cataract still accounting for one third of all global blindness. A great deal of progress has been made in increasing cataract surgical rates or productivity, and associated cost containment. However, there is currently no audit tool which facilitates capture of routine cataract surgical productivity, solid waste, carbon, and cost-related data which could be used for global benchmarking, learning, and improvement. The Eyefficiency tool, discussed here, develops a universal Life Cycle Assessment (LCA) methodology for cataract surgery to identify opportunities for sites to minimize the footprint of cataract surgical services and increase access to cataract surgery for patients worldwide.Here, we describe the LCA approaches tested for use in Eyefficiency, with the goals of creating an easy-to-use, open source tool that is also easy to maintain and update. Given those goals, the development team chose to use a hybrid LCA approach with UK-based process and environmental extended input–output inventories. The carbon results of the Eyefficiency tool are compared to previous studies at two of Eyefficiency's pilot test sites. Though Eyefficiency's carbon calculator may only provide order of magnitude accuracy, it offers cataract surgical providers everywhere in the world an opportunity to benchmark their costs, throughput, waste generation, and carbon emissions. Eyefficiency enables ground level ownership in sustainable pathways for the most common medical procedure worldwide.

Life cycle energy consumption and greenhouse gas emissions of urban residential buildings in Guangzhou city

Abstract Carbon emissions are derived mainly from the building, industrial, and transport sectors. Buildings are responsible for more than 40% of global energy use and for as much as 33% of global greenhouse gas emissions. By the end of 2016, 57.4% of the total population lived in urban areas in China, a dramatic increase from 26% in 1990. It is essential to study and analyze both energy consumption and carbon emissions of buildings. Taking Guangzhou city of China as an example, this study applied a hybrid life cycle assessment approach to quantify both the energy consumption and CO2 emissions throughout the life cycle of an urban residential building. The data was collected from the Guangzhou input–output (IO) table of 2012, Guangzhou Statistical Yearbook of 2013, China Electric Power Yearbook of 2013, and statistical data of the studied building. Results showed that the overall life cycle energy consumption and CO2 (eq.) emissions for the studied building, constructed in 2012, were approximately 72,591.98 GJ and 12,637.32 t, respectively. The largest CO2 (eq.) emission factor was oil and the smallest one was electricity. The CO2 emissions of steel, concrete, brick, and cement together accounted for 76.69% of the total emissions which are related to building materials in the preparation stage. This research not only promotes the construction of eco-cities or eco-communities, but also provides decision makers with comprehensive data on the energy consumption and environmental impacts of residential buildings. The findings are of considerable importance in terms of energy saving and emissions reductions for society as a whole.

Environmental and natural resource implications of sustainable urban infrastructure systems

As cities grow, their environmental and natural resource footprints also tend to grow to keep up with the increasing demand on essential urban services such as passenger transportation, commercial space, and thermal comfort. The urban infrastructure systems, or socio-technical systems providing these services are the major conduits through which natural resources are consumed and environmental impacts are generated.This paper aims to gauge the potential reductions in environmental and resources footprints through urban transformation, including the deployment of resource-efficient socio-technical systems and strategic densification. Using hybrid life cycle assessment approach combined with scenarios, we analyzed the greenhouse gas (GHG) emissions, water use, metal consumption and land use of selected socio-technical systems in 84 cities from the present to 2050. The socio-technical systems analyzed are: (1) bus rapid transit with electric buses, (2) green commercial buildings, and (3) district energy. We developed a baseline model for each city considering gross domestic product, population density, and climate conditions. Then, we overlaid three scenarios on top of the baseline model: (1) decarbonization of electricity, (2) aggressive deployment of resource-efficient socio-technical systems, and (3) strategic urban densification scenarios to each city and quantified their potentials in reducing the environmental and resource impacts of cities by 2050.The results show that, under the baseline scenario, the environmental and natural resource footprints of all 84 cities combined would increase 58%–116% by 2050. The resource-efficient scenario along with strategic densification, however, has the potential to curve down GHG emissions to 17% below the 2010 level in 2050. Such transformation can also limit the increase in all resource footprints to less than 23% relative to 2010. This analysis suggests that resource-efficient urban infrastructure and decarbonization of electricity coupled with strategic densification have a potential to mitigate resources and environmental footprints of growing cities.

Environmental and economic hybrid life cycle assessment of bagasse-derived ethanol produced in Brazil

Purpose The goal of this study is to identify which processes contribute most to fuel CO2e emissions, energy use, and employment generation when driving a typical Brazilian flex fuel vehicle (FFV) model with bagasse-derived ethanol. A hybrid life cycle assessment (LCA) is used to report the associated impacts and a structural path analysis (SPA) is utilized to identify, quantify, and rank the highest carbon emissions, energy use, and employment generation input paths in the supply chain of bagasse-derived ethanol. Additionally, this study explores the integrated hybrid LCA approach as a tool to explain the economic impacts of bagasse-derived ethanol.

Hybrid Life Cycle Assessment of Low, Mid and High-Rise Multi-Family Dwellings

We undertake Life Cycle Assessment (LCA) of the cumulative energy demand (CED) and global warming potential (GWP) for a portfolio of 10 multi-family residences in the U.S. We argue that prior LCA studies of buildings use an inconsistent boundary for processes to be included in the supply chain: The operational phase includes all energy use in a building, but supply chains for the production of appliances, equipment and consumables associated with activities done in the building are neglected. We correct this by starting the analysis with an explicit definition of a functional unit, providing climate controlled space, and including processes associated with this functional unit. Using a hybrid LCA approach, the CED for low, mid and high-rise multi-family residences is found to increase from 30, 34, to 39 GJ/m2, respectively. This increase is due to the need for energy-intensive structural materials such as concrete and steel in taller buildings. With our approach, the share of materials and construction of total life cycle energy doubles to 26%, compared with a 13% share that would be obtained with inconsistent system boundaries used in prior studies. We thus argue that explicit definition of functional unit leads to an increase in the contribution of supply chains to building energy life cycles.

Global Supply Chains of Coltan

SummaryThe spot price for tantalum, a metal used in high‐performance consumer electronics, spiked in 2000, triggering a boom in artisanal mining of surface deposits in the Democratic Republic of Congo (DRC). The profit from columbite‐tantalite ore, or coltan, is alleged to have funded militants during that country's civil war. One warlord famously claimed that in 2000, coltan delivered a million dollars per month. While coltan mining was neither a necessary nor sufficient cause for the civil war, there is nevertheless a clear association between mining and conflict. In order to trace global flows of coltan out of the DRC, we used a high‐resolution multiregion input‐output (MRIO) table and a hybrid life cycle assessment (LCA) approach to trace exports through international supply chains in order to estimate a “coltan footprint” for various products. In this case study, our aim is to highlight the power and utility of hybrid LCA analysis using high‐resolution global MRIO accounts. We estimate which supply chains, nations, and consumer goods carry the largest loads of embodied coltan. This hybrid LCA case study provides estimates on illicit flows of coltan, estimates a coltan footprint of consumption, and highlights the advantages and challenges of using hybrid monetary‐physical input‐output/LCA approaches to study and quantify a negative social impact as an input to production. If successful, the hybrid LCA approach could be a useful and expedient measurement tool for understanding flows of conflict minerals embodied in supply chains.

English

The developmental path taken globally over the past few decades has been ultimately detrimental to the health of our surroundings leading to problems of excessive natural resource depletion, waste generation and environmental stress through harmful emissions. The construction industry being a major contributor to these problems, now faces increasingly restrictive environmental conservation and protective, laws, and regulations. Yet at present, there has been a lack of sufficient, credible and reliable quantitative indictors, metrics and/or data on the actual benefits of sustainable construction. In particular, reduction of environmental effects during construction activities has been one of the main issues facing stakeholders. To address this problem, this study identifies materials and energy flows during construction and develops a method to quantify and measure environmental impacts during raw materials extraction, production, fabrication and installation. By using a Hybrid Life Cycle Assessment approach, this paper provides a detailed assessment of both direct and supply chain impacts. The results quantify and compare the two floor systems in terms oftheir environmental impacts.

Scope-based carbon footprint analysis of U.S. residential and commercial buildings: An input–output hybrid life cycle assessment approach

Analyzing building related carbon emissions remains as one of the most increasing interests in sustainability research. While majority of carbon footprint studies addressing buildings differ in system boundaries, scopes, GHGs and methodology selected, the increasing number of carbon footprint reporting in response to legal and business demand paved the way for worldwide acceptance and adoption of the Greenhouse Gas Protocol (GHG Protocol) set by the World Resources Institute (WRI) and World Business Council for Sustainable Development (WBCSD). Current research is an important attempt to quantify the carbon footprint of the U.S. residential and commercial buildings in accordance with carbon accounting standards and Scopes set by WRI, in which all possible indirect emissions are also considered. Emissions through the construction, use, and disposal phases were calculated for the benchmark year 2002 by using a comprehensive hybrid economic input–output life cycle analysis. The results indicate that emissions from direct purchases of electricity (Scope 2) with 48% have the highest carbon footprint in the U.S. buildings. Indirect emissions (Scope 3) with 32% are greater than direct emissions (Scope 1) with 20.4%. Commuting is the most influential activity among the Scope 3 emissions with more than 10% of the carbon footprint of the U.S. buildings overall. Construction supply chain is another important contributor to the U.S. building's carbon footprint with 6% share. Use phase emissions are found to be the highest with 91% of the total emissions through all of the life cycle phases of the U.S. buildings.

Assessment of the embodied carbon in precast concrete wall panels using a hybrid life cycle assessment approach in Malaysia

Abstract There is currently growing interest in quantifying the direct and indirect carbon emissions embodied in construction materials and their components production. Previous research shows that indirect emission could be higher than direct emission for energy intensity materials such as cement and steel reinforcement. Quantifying direct emissions alone would underestimate the carbon emissions associated with a material and in turn its environmental impact. The assessment of indirect emissions is a challenging task involving upstream processes of material production. This paper investigates the existing literature on the quantification of embodied carbon by both direct and indirect emissions as well as demonstrating the application of a hybrid life cycle assessment method in building construction. The focus of this paper is the Malaysian context however the principles apply universally. A typical 2-storey residential building has been investigated to determine the total carbon emissions when comparing two construction techniques: conventionally reinforced concrete and precast concrete panels. This paper demonstrates the application of hybrid life cycle assessment by expanding the boundaries of process methods and reducing the sensitivities of I–O life cycle assessment to the raw material price fluctuation for product manufacturing.

Carbon footprint evaluation at industrial park level: A hybrid life cycle assessment approach

Industrial parks have become the effective strategies for government to promote sustainable economic development due to the following advantages: shared infrastructure and concentrated industrial activities within planned areas. However, due to intensive energy consumption and dependence on fossil fuels, industrial parks have become the main areas for greenhouse gas emissions. Therefore, it is critical to quantify their carbon footprints so that appropriate emission reduction policies can be raised. The objective of this paper is to seek an appropriate method on evaluating the carbon footprint of one industrial park. The tiered hybrid LCA method was selected due to its advantages over other methods. Shenyang Economic and Technological Development Zone (SETDZ), a typical comprehensive industrial park in China, was chosen as a case study park. The results show that the total life cycle carbon footprint of SETDZ was 15.29Mt, including 6.81Mt onsite (direct) carbon footprint, 8.47Mt upstream carbon footprint, and only 3201t downstream carbon footprint. Analysis from industrial sector perspectives shows that chemical industry and manufacture of general purpose machinery and special purposes machinery sector were the two largest sectors for life cycle carbon footprint. Such a sector analysis may be useful for investigation of appropriate emission reduction policies.

Integrated Techno-economic and Environmental Assessment of an Amine-based Capture

A systematic methodology for integrated techno-economic and environmental assessment of CCS value chains is presented and applied to assess the impact of the CO2 concentration on an amine-based post-combustion CO2 capture process. In this methodology, the technical assessment, economic evaluation, and environmental assessment (focusing on the global warming effect) are integrated in order to avoid the unilateral understandings obtained when these assessments are performed separately. Seven cases with CO2 concentrations between 2.5 and 20.5% (mol) are investigated in terms of energy consumptions, the overall costs, as well as the climate impact of the capture process. The process simulation is performed with Aspen Plus®, and the techno-economic evaluation using Aspen Process Economic Analyzer®. A hybrid life cycle assessment approach is used to estimate the climate impact of the capture based on the results of techno-economic assessment. The CO2 avoided capture cost, which reflects both the techno- economic and environmental performances, is used to assess the comprehensive impact of the CO2 concentration on the capture process.

Scenarios for the environmental impact of fossil fuel power: Co-benefits and trade-offs of carbon capture and storage

This study uses a hybrid Life Cycle Assessment approach to evaluate the environmental impacts of large-scale deployment of Carbon dioxide Capture and Storage (CCS) in coal and natural gas based electricity generation, based on IEA scenarios. For the Baseline scenario, all impact categories would increase 2–3-fold in 2050 from 2005 levels. Green House Gas (GHG) emissions are found to decrease by ∼40% in ACTmap scenario and by ∼75% in more CCS-intensive BLUEmap scenario. These climate mitigation scenarios also show significantly reduced impacts of acidification, particulate matter formation and human toxicity, suggesting the existence of co-benefits. For eutrophication, all scenarios indicate substantial increases, but the increases are largest in the Baseline scenario. For photochemical oxidant formation, only the mitigation scenarios manage to stabilize this impact from fossil fuel based power production. This study does not assess the impact of alternative power generation or energy efficiency technology that replaces part of the fossil fuel power in the mitigation scenarios.

Insights on the Use of Hybrid Life Cycle Assessment for Environmental Footprinting

Summary Establishing a comprehensive environmental footprint that indicates resource use and environmental release hotspots in both direct and indirect operations can help companies formulate impact reduction strategies as part of overall sustainability efforts. Life cycle assessment (LCA) is a useful approach for achieving these objectives. For most companies, financial data are more readily available than material and energy quantities, which suggests a hybrid LCA approach that emphasizes use of economic input-output (EIO) LCA and process-based energy and material flow models to frame and develop life cycle emission inventories resulting from company activities. We apply a hybrid LCA framework to an inland marine transportation company that transports bulk commodities within the United States. The analysis focuses on global warming potential, acidification, particulate matter emissions, eutrophication, ozone depletion, and water use. The results show that emissions of greenhouse gases, sulfur, and particulate matter are mainly from direct activities but that supply chain impacts are also significant, particularly in terms of water use. Hotspots were identified in the production, distribution, and use of fuel; the manufacturing, maintenance, and repair of boats and barges; food production; personnel air transport; and solid waste disposal. Results from the case study demonstrate that the aforementioned footprinting framework can provide a sufficiently reliable and comprehensive baseline for a company to formulate, measure, and monitor its efforts to reduce environmental impacts from internal and supply chain operations.

Calculation of Greenhouse Gas Emissions for Highway Construction Operations by Using a Hybrid Life-Cycle Assessment Approach: Case Study for Pavement Operations

Large quantities of greenhouse gases (GHG) are emitted in producing and acquiring materials for the construction, maintenance, and rehabilitation of highway infrastructure. The objective of this paper is to develop and illustrate a method that can be applied by state agencies to quantify the life-cycle emissions associated with different pavement designs. It applies existing life-cycle assessment (LCA) methods that integrate process-level construction data. The research emphasizes the construction phase and contributes a method that can be used to develop and analyze construction phase life-cycle inventories. It describes on-site collection of material and equipment usage data during construction and rehabilitation operations. Departing from traditional approaches that tend to use LCA as a way to compare alternative pavement materials or designs on the basis of estimated inventories, this paper proposes a shift to a context-sensitive process-based approach that uses actual observed construction data to ca...

A comment on “Functions, commodities and environmental impacts in an ecological–economic model”

In a recent paper in this journal, Suh [Suh, S., 2004. Functions, commodities and environmental impacts in an ecological-economic model. Ecological Economics 40 (4), 451-467.] presented a model combining life cycle assessment (LCA) with input–output analysis (IOA); termed “integrated hybrid LCA”. In this paper, we discuss various issues relating to the use of the integrated hybrid LCA approach. In particular, the interpretation of the downstream feedback term, C d, is discussed with particular focus on practical implementation. In this paper, two interpretations of C d are suggested depending on the particular LCA data used. If the LCA data is designed for a demand on the functional unit only, then it is argued that the C d term is negligible in many applications. If the LCA data is compatible with an arbitrary demand, then it is argued that in many cases the consistent use of the C d term implies data requirements that may not be justified by the potential gains.

Life Cycle Energy Assessment of Alternative Water Supply Systems (9 pp)

This paper discusses the merging of methodological aspects of two known methods into a hybrid on an application basis. Water shortages are imminent due to scarce supply and increasing demand in many parts of the world. In California, this is caused primarily by population growth. As readily available water is depleted, alternatives that may have larger energy and resource requirements and, therefore, environmental impacts must be considered. In order to develop a more environmentally responsible and sustainable water supply system, these environmental implications should be incorporated into planning decisions. Comprehensive accounting for environmental effects requires life cycle assessment (LCA), a systematic account of resource use and environmental emissions caused by extracting raw materials, manufacturing, constructing, operating, maintaining, and decommissioning the water infrastructure. In this study, a hybrid LCA approach, combining elements of process-based and economic input-output-based LCA was used to compare three supply alternatives: importing, recycling, and desalinating water. For all three options, energy use and air emissions associated with energy generation, vehicle and equipment operation, and material production were quantified for life-cycle phases and water supply functions (supply, treatment, and distribution). The Water-Energy Sustainability Tool was developed to inform water planning decisions. It was used to evaluate the systems of a Northern and a Southern California water utility. The results showed that for the two case study utilities desalination had 2–5 times larger energy demand and caused 2–18 times more emissions than importation or recycling, due primarily to the energy-intensity of the treatment process. The operation life-cycle phase created the most energy consumption with 56% to 90% for all sources and case studies. For each water source, a different life-cycle phase dominated energy consumption. For imported water, supply contributed 56% and 86% of the results for each case study; for desalination, treatment accounted for approximately 85%; for recycled water, distribution dominated with 61% and 74% of energy use. The study calculated external costs of air pollution from all three water supply systems. These costs are borne by society, but not paid by producers. The external costs were found to be 6% of desalinated water production costs for both case studies, 8% of imported water production costs in Southern California, and 1–2% for the recycled water systems and for the Northern California utility's imported water system. Recycling water was found to be more energy intensive in Northern than in Southern California, but the results for imported water were similar. While the energy demand of water recycling was found to be larger than importation in Northern California, the two alternatives were competitive in Southern California. For all alternatives in both case studies, the energy consumed by system operation dominated the results, but maintenance was also found to be significant. Energy production was found to be the largest contributor in all water provision systems, followed by materials production. The assessment of external costs revealed that the environmental effects of energy and air emissions caused by infrastructure is measurable, and in some cases, significant relative to the economic cost of water. This paper advocates the necessity of LCA in water planning, and discusses the applicability of the described model to water utilities.

Life-Cycle Methods for Comparing Primary and Rechargeable Batteries

Life-Cycle Assessment (LCA) can be used to improve the environmental performance of products throughout their life cycle. With ongoing discussions about system boundaries, appropriate data, and model limitations, LCA methods are in a constant state of evolution. This paper presents the use of a hybrid LCA approach to product environmental assessment in which two methods of analysis are combined to present the total environmental impact for two battery systems. A quantitative model for product assessment has been developed at Carnegie Mellon. The model is based on economic input−output life-cycle analysis (EIO-LCA) and has been explained in previous works. The EIO-LCA tool allows a user to quantify the direct and indirect relationships among industry sectors and the associated environmental burdens through the materials extraction and manufacturing phases. However, to study environmental effects over a product's entire life, use and end-of-life impacts must also be quantified. This is accomplished using th...