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Concepts for setting carrying capacity-based benchmarking of life-cycle environmental impacts is an ongoing field of research with an emerging industrial uptake in the built environment. This paper is a critical review of this development compiled in the form of 10 questions that discusses issues and challenges related to definitions, methodology, terminology, and uncertainties. The intention is not to discourage the development but to highlight the need for ensuring consensus and alignment on the aforementioned issues both within the research community and when implementing concepts in practice. Concluding that AESA (Absolute Environmental Sustainability Assessment) aims to address the environmental performance of a service, benchmarked against a functional pollution space, using environmental carrying capacities, rather than comparing it to current 'best practice'. It is crucial to recognize that these carrying capacities are limits, not targets, and whilst allocation of the carrying capacity to services depends on subjective and political decision-making, uncertainties, including subjectivity and emerging scientific data, should be included and communicated clearly in credible AESAs. Collaboration between academia and industry is crucial to align definitions and terminology and avoid misalignments. While AESA lacks a scalable approach for systemic assessments, it serves as a valuable steppingstone for transition, highlighting that achieving a built environment within the currently known functional pollution spaces, requires policy changes and a cultural shift. • Status of research and pitfalls when implementing AESA in the building industry. • Ten questions and answers are posed on AESAs in the Built Environment. • AESA should be based on carrying capacities, defining a functional pollution space. • It is crucial to recognize that carrying capacities are limits, not targets. • Uncertainties should be included and communicated clearly in credible AESAs. [ABSTRACT FROM AUTHOR]

Abstract During the use stage of buildings, their consumption of electricity has proved to influence considerably their environmental performance. The impacts associated with using electricity are directly related to the electricity grid that delivers the power and hence are also closely associated with the impacts induced by the production of each kWh delivered to the grid. Life cycle assessment (LCA) usually does not account for the variations in the energy sources that supply an electricity grid every day, month and year. This study addresses the dynamic nature of electricity grids and accounts for the source variations in electricity production using electricity grid data at high temporal resolutions. The study compares inventory data on electricity grid composition at hourly, daily and monthly resolutions with the conventional yearly average grid compositions from the ecoinvent database. The high-resolution electricity grid inventory data are subsequently paired with data sets for electricity consumption by buildings with matching resolutions in order to quantify the differences in the environmental performance of buildings resulting from the application of temporally high-resolution grid data. Finally, environmental building performance (EBP) calculated using high-resolution grids is compared to EBPs generated from conventional data resolutions. The results indicate that the contribution to global warming potential is closely related to the data resolution of the grid composition and that the EBP may be overestimated by up to a factor of two when compared with conventional grid inventory data with yearly (i.e. low) data resolutions. Highlights • Substantial changes occur in the electrical grid composition throughout the year. • Environmental impact potential pr. kWh changes by the hour. • There are notable differences in LCIA results when changing the data resolution. • Combination of production and consumption data of equal resolutions yield most accurate assessment. • Static assessment framework yields substantially higher impact scores compared to dynamic counterpart. [ABSTRACT FROM AUTHOR]

Highlights • National targets for embedded GHG emissions are calculated from the climate goal of the Paris Agreement. • Four explorative consumption scenarios for 2050 are derived based on a large survey of individuals in Denmark. • Reductions in GHG emission intensities of technologies required to meet national emission targets are estimated. • These estimates are compared to historic time series of emission intensities and future scenarios for ten selected technologies. • Results strongly suggest that both changes in "business as usual" and "consumption as usual" are needed. Abstract The COP21 summit in Paris led to a policy commitment of limiting the global temperature increase to 1.5–2.0 °C and this can be translated to a global annual greenhouse gas (GHG) emission budget that is shrinking rapidly throughout the 21st century. Here, we estimate the reductions in GHG emission intensities of technologies that will be required for the embedded GHG emissions of a developed nation to stay within its fair share of a global emission budget in the year 2050. The estimates are made for different conceivable developments in consumption patterns in the case of Denmark, based on a large survey of current consumption patterns. To evaluate whether the required emission intensity reductions are likely to be met, they are compared to historic time series of emission intensities and to projections for 2050, based on policies currently in place, for ten technologies that have a high contribution to current GHG emissions. We estimate that emission intensities must be reduced by factors of 2–12 and 5–14, depending on the development in consumption, for the 2.0 and 1.5 °C climate goals, respectively. Of the ten selected technologies, only electricity supply is projected to, partially, meet the most strict reduction target, applying to a scenario where all inhabitants in 2050 consume as the most consuming inhabitants today. The results indicate that both a change in "consumption as usual" and in "business as usual" is needed for developed nations to meet equitable climate targets. This has implications for national and international policies targeting GHG emission intensities and may require a new orientation of policies to consider the societal structures around consumption. [ABSTRACT FROM AUTHOR]

It is essential to provide quantitative decision support when pursuing environmental impact mitigation efforts, particularly when considering resource and energy-demanding sectors such as the built environment. Life cycle assessment (LCA) provides widely recognized quantitative decision support regarding environmental performance. However, for long-lived products such as buildings, the usefulness of conventional LCA is limited as it relies on databases that only give a current or past representation of industrial processes. The emerging field of prospective LCA (pLCA) allows us to evaluate the results at a future point in time based on technological and socio-economic projections. This article builds on a systematic literature screening, ongoing discussions in the pLCA academic community, and hands-on experimentation with available software. The goal of the study is to 1) understand implications of how pLCA is conducted, and how it relates to the built environment; 2) Improve the documentation and credibility of pLCA and applied scenarios; And 3) identify practical tools and workflows that can make pLCA more accessible to practitioners. The study raises ten relevant questions when considering how to use pLCA for decision support in the built environment. This list of questions is not exhaustive nor definite, and recommendations are possible answers suggested by the authors. Using scenario narratives from energy and Integrated Assessment Models allows for systematic and consistent transformation of LCA databases to represent possible futures. However, there is a need for pLCA practitioners to improve documentation to ensure that the goal and scope of the LCA are compatible with the chosen future scenario. In the case of built environment, it is relevant to consider different projection years when modeling construction, operation, renovation, and demolition phases, respectively, as they span several decades. Not doing so can misestimate the effects changing socio-economic and technological contexts have on the life-cycle impact of buildings. • pLCA evaluates results at a future point in time based on future LCI projections. • Ten relevant questions and answers are formulated for pLCA in the built environment. • Answers based on literature review, community discussions, and practical experience. • pLCA benefits from exploring different scenario narratives, such as SSPs and RCPs. • Software tools, which can support pLCA practitioners are identified and discussed. [ABSTRACT FROM AUTHOR]

Our paper presents a novel approach for absolute sustainability assessment of a building's environmental performance. It is demonstrated how the absolute sustainable share of the earth carrying capacity of a specific building type can be estimated using carrying capacity based normalization factors. A building is considered absolute sustainable if its annual environmental burden is less than its share of the earth environmental carrying capacity. Two case buildings – a standard house and an upcycled single-family house located in Denmark – were assessed according to this approach and both were found to exceed the target values of three (almost four) of the eleven impact categories included in the study. The worst-case excess was for the case building, representing prevalent Danish building practices, which utilized 1563% of the Climate Change carrying capacity. Four paths to reach absolute sustainability for the standard house were proposed focusing on three measures: minimizing environmental impacts from building construction, minimizing impacts from energy consumption during use phase, and reducing the living area per person. In an intermediate path, absolute sustainability can be obtained by reducing the impacts from construction by 89%, use phase energy consumption by 80%, and the living area by 60%. [ABSTRACT FROM AUTHOR]

Carbon footprint (CFP) is widely applied as an indicator when assessing environmental sustainability of products and services. The objective of the present study is to evaluate the validity of CFP as overall environmental indicator for representing the environmental burden of residents from urbanized areas. Applying four different Life Cycle Impact Assessment (LCIA) methods environmental impact profiles were determined for the consumption patterns of 1281 Danish urban residents. Six main consumption components were distinguished including road transport, air travel, food, accommodation (covering consumption of materials for the construction of dwellings) and use of energy in terms of thermal energy, and electricity. The results for the individual consumption components showed a strong correlation between CFP and nearly all other impact indicators for all the applied LCIA methods However, upon aggregation of the indicator results across consumption components, the impact indicators for the total consumption showed no significant correlation between CFP and the other impact scores for any of the four impact assessment methods. These findings suggest that while CFP can be a good indicator of the environmental burden associated with specific activities, this is not the case for more complex activities (such as consumption patterns related to urban life styles). This conclusion discourages the use of CFP as sustainability measure in relation to regulation of private or public consumption. [ABSTRACT FROM AUTHOR]

Residential building insulation is regarded as an easy solution for environmentally friendly building design. This assumption is based on the perception that the amount of thermal energy used to create insulation in most cases is much smaller than the amount of thermal energythat is needed for space heating without insulation over the lifespan of a building. When the energy sources for insulation production are similar to the energy mix that supplies heat, this logic is valid to very high level of insulation. However, in Denmark, as well as many other countries this assumption is becoming increasingly incorrect. Given the generally long service life of buildings, the significance of future energy mixes, which are expected/intended to have a smaller environmental impact, can be great. In this paper, a reference house is used to assess the life cycle environmental impacts of mineral wool insulation in a Danish single-family detached home. This single-family house, is based on averages of current Danish construction practices with building heat losses estimated using Be10. To simulate a changing district heating grid mix, heat supply fuel sources are modeled according to Danish energy mix reports of fuel mix since 1972. Both the dynamic impact potentials saved by using insulation and the impacts induced from insulation's production are utilized to create an overall dynamic energy inventory for the lifecycle assessment. Our study shows that the use of such a dynamic energy inventory is necessary for increasing the validity of optimization assessment, and our study further shows that it is likely that current Danish regulation will not promote optimum levels of insulation in the near future. [ABSTRACT FROM AUTHOR]

The purpose of this work is to compare the environmental impacts of spring barley cultivation in Denmark under current (year 2010) and future (year 2050) climatic conditions. Therefore, a Life Cycle Assessment was carried out for the production of 1 kg of spring barley in Denmark, at farm gate. Both under 2010 and 2050 climatic conditions, four subscenarios were modelled, based on a combination of two soil types and two climates. Included in the assessment were seed production, soil preparation, fertilization, pesticide application, and harvest. When processes in the life cycle resulted in co-products, the resulting environmental impacts were allocated between the main product and their respective by-products using economic allocation. Impact assessment was done using the ReCiPe (H) methodology, except for toxicity impacts, which were assessed using USEtox. The results show that the impacts for all impact categories, except human and freshwater eco-toxicity, are higher when the barley is produced under climatic circumstances representative for 2050. Comparison of the 2010 and 2050 climatic scenarios indicates that a predicted decrease in barley yields under the 2050 climatic conditions is the main driver for the increased impacts. This finding was confirmed by the sensitivity analysis. Because this study focused solely on the impacts of climate change, technological improvements and political measures to reduce impacts in the 2050 scenario are not taken into account. Options to mitigate the environmental impacts are discussed. [ABSTRACT FROM AUTHOR]

Sustainable and informed resource consumption is the key to make everyday living sustainable for entire populations. An intelligent and strategic way of addressing the challenges related with sustainable development of the everyday living of consumers is to identify consumption-determined hotspots in terms of environmental and health burdens, as well as resource consumptions. Analyzing consumer life styles in terms of consumption patterns in order to identify hotspots is hence the focus of this study. This is achieved by taking into account the entire value chain of the commodities consumed in the context of environmental and human health burdens, as well as resource consumptions. A systematic commodity consumption, commodity disposal, and life style survey of 1281 persons living in urbanized Danish areas was conducted. The findings of the survey showed new impact dimensions in terms of Personal Metabolism (PM) patterns of residents living in urbanized areas of Denmark. Extending the PM analysis with Life Cycle Assessment (LCA) provided a clear picture of the per capita environmental and human health burdens, as well as resource consumptions, and the exact origin hereof. A generic PM-LCA Model for all the 1281 persons was set-up in Gabi 6. The assessment results obtained applying the model on all 1281 personal consumption scenarios yielded the 1281 Personal Impact Profiles (PIPs). Consumption of food and energy (electricity and thermal energy) proved to be the primary impact sources of PM, followed by transport. The PIPs further revealed that behavioral factors ( e.g. different diets, use of cars, household size) affect the profiles. Hence, behavioral changes are one means out of many that humanity will most likely have to rely on during the sustainable development process. The results of this study will help the Danish and other comparable populations to identify and prioritize the steps towards reducing their environmental, human health, and resource consumption burdens. [ABSTRACT FROM AUTHOR]

As companies try to embrace life cycle thinking, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) have proven to be powerful tools. In this paper, an Environmental Input-Output model is used for analysis as it enables an LCA using the same economic input data as LCC. This approach helps align LCA and LCC while avoiding cut-offs in the LCA. The efficacy of the method is illustrated by a real case study of a tanker ship. [ABSTRACT FROM AUTHOR]

This paper assesses the environmental impacts of conventional and modular housing by applying measures of 'absolute environmental sustainability'. It seeks to determine 1) the environmental performance of typical housing across different geographic boundaries, in this case Australia and Denmark, to explore whether such buildings can be deemed to achieve absolute sustainability within the planetary boundaries, and how factors related to location impact this, and 2) whether modular buildings perform better in terms of absolute environmental sustainability. The research measures lifecycle environmental performance of four case study buildings (conventional and modular, in Australia and Denmark), across seven impact categories. Normalisation references are determined based on the carrying capacity of earth by allocating a percentage of its limited resources to housing. A building would be considered to achieve absolute environmental sustainability if its environmental burden is less than its allocated share of the carrying capacity. The results found that none of the four buildings met this criterion. The two Australian buildings exceeded their allocated capacity in six of the seven impact categories, with figures of 700–36,000% above capacity. The two Danish buildings did so in five of the seven categories, with figures of 200–3700% above. Modular buildings generally had lower environmental impacts across all categories, but still exceeded their allocations. The primary contributor was the operational phase of the buildings' lifecycle. However, even when this was excluded, all four buildings' impacts remain above their allocated limits, suggesting that environmental reductions are necessary across both embodied and operational stages. • Environmental impacts of conventional and modular housing, applying measures of 'absolute environmental sustainability'. • No studied case satisfied allocated absolute environmental sustainability measure across all included impact categories. • Modular case study building designs perform better, relatively compared to the conventional counterpart. • Comparison between countries helps highlight different issues in need of focus. • Economic household or dwelling allocation performed should be further developed. [ABSTRACT FROM AUTHOR]

Abstract: Life cycle assessment (LCA) involves assessment of resource consumption and emissions caused by the provision of a given service over the whole life cycle of the products it involves, from the cradle to the grave. The quantification of exchanges with the environment during the life cycle of a product or service is a specific element of LCA termed life cycle inventory (LCI). Estimation of chemical emissions in agricultural LCA is typically based on standard emission factors which at best are determined by a few physical–chemical substance properties and the use scenario of the chemical compound. Dynamic and realistic models capable of predicting compartment specific mode of entry fractions for various chemicals and uses under specific temporal and use circumstances are scarce. This lack of appropriate models to estimate emission fractions results in a lower accuracy when accounting for one of the major corner stones in any LCA, chemical emissions, and it inevitably influences the outcome of the impact assessment, where the environmental impacts are normally assumed proportional to the emissions in LCA. PestLCI is a modular model for estimation of pesticide emissions from field application to the different environmental compartments. It estimates the fractions of the applied quantity which is emitted to the air, surface water, and groundwater compartment based on information which will normally be available to the model user about: type and time of application, crop species and development stage, geological and meteorological conditions and the area of application, and properties of the active ingredients of the pesticide. The use and capability of the model is illustrated through two realistic Danish case studies, but the modular structure of the model will allow adaptation to conditions valid for other regions of the world. [Copyright &y& Elsevier]

The purpose of this study was to assess: what are the circular economy opportunities for small and medium-sized enterprises (SME) in the meat processing sector to reduce their environmental impacts, using Life cycle assessment (LCA) as the analytical method to prevent burden shifting; whether current life cycle inventories and LCA studies adequately represent SMEs such as the study plant; and whether climate change is a suitable proxy for impacts. Life cycle inventory data from a SME meat processing site in regional Australia was used for benchmarking with existing industry data and for risk and opportunity identification along the supply chain. A LCA was conducted of the current operation and possible future energy supply scenarios involving the use of tallow, wastewater methane and biomass production, to identify the best performing option as part of a PhD project on SMEs and sustainability in agribusiness value chains. System expansion was used to handle all coproducts and byproducts. The area of land required to produce biomass was calculated and was compared to the catchment area for livestock, and an estimate was made of the non-arable land area required to produce biomass to offset all greenhouse emissions for the supply chain. Inventory data and LCA results for this SME were significantly different to previous LCAs. The system expansion resulted in large credits, particularly for edible offal. Climate change may not be a suitable proxy for other midpoint impact categories due to the difference in contributing processes. The best future energy appeared to be the biomass scenario, which involved using tallow for biodiesel production, capturing methane generated in the onsite wastewater treatment system for electricity generation, using tallow to generate the remaining electricity needs and using biomass for thermal energy production. Less than 0.5% of the non-arable land area required for producing the livestock for the plant was needed for biomass production, and if all supply chain emissions were offset using biomass, the land area required was 12% for life time grass fed beef. The potential for supply chain integration in the red meat sector appears promising, particularly in terms of offsets from biomethane use for electricity production, tallow use for biodiesel production and biomass production for thermal energy use. Life cycle assessment is a useful tool to screen circular economy options and identify the best future scenario, although a wide range of impact categories should be assessed as climate change may not be a suitable proxy. • Optimising use of edible offal is important for reducing impacts of meat production. • Meat processing SMEs may not be adequately represented by current inventory data. • Climate change may not be a suitable proxy for all other mid point impact categories. • Biomass scenario appears to be the best, utilising biogas and tallow for transport biodiesel. • Less than 0.5% of livestock catchment required to grow biomass. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate absolute environmental sustainability in the built environment, by assessing whether contemporary environmentally optimized approaches to building design, with their associated consumption of resources and subsequent emissions, can be considered within the carrying capacity of Earth Systems. A life cycle assessment (LCA) was conducted for six dwellings to quantify their environmental footprints. Two methods for absolute environmental sustainability assessment were applied to the resulting life cycle inventories; one where the normalisation step applied normalisation factors reflecting carrying capacities of the Earth System and one where characterisation of elementary flows applied characterisation factors based on the Planetary Boundaries. For the assessment of environmental impact of each house in an absolute perspective, different sharing principles were applied to determine the share of the safe operating space that a single-family stand-alone dwelling should be assigned. The study finds that the approaches tested in two of the dwellings, namely reducing the energy consumption and recycling and reusing materials have the greatest potential to reach an absolute sustainable level of impact. The conclusions drawn are found to be dependent of the applied sharing principle used to assign a share of the safe operating space. Nevertheless, as the results indicate that in our current society absolute sustainability for buildings still appear to be out of reach, even with the best attempts at sustainable building design. It is clear that to achieve e.g. lower energy consumption and a cleaner energy mix, action is needed by consumers and politicians alike. • Benchmarks based on the carrying capacity allows more dwellings to be absolute sustainable. • The absolute benchmark is highly dependent on the considered sharing principle. • Current approach to environmentally optimized building design is not absolute sustainable. • No great difference on sustainability strategies in terms of absolute performance. [ABSTRACT FROM AUTHOR]

We present a second-generation wastewater treatment inventory model, WW LCI 2.0, which on many fronts represents considerable advances compared to its previous version WW LCI 1.0. WW LCI 2.0 is a novel and complete wastewater inventory model integrating WW LCI 1.0, i.e. a complete life cycle inventory, including infrastructure requirement, energy consumption and auxiliary materials applied for the treatment of wastewater and disposal of sludge and SewageLCI, i.e. fate modelling of chemicals released to the sewer. The model is expanded to account for different wastewater treatment levels, i.e. primary, secondary and tertiary treatment, independent treatment by septic tanks and also direct discharge to natural waters. Sludge disposal by means of composting is added as a new option. The model also includes a database containing statistics on wastewater treatment levels and sludge disposal patterns in 56 countries. The application of the new model is demonstrated using five chemicals assumed discharged to wastewater systems in four different countries. WW LCI 2.0 model results shows that chemicals such as diethylenetriamine penta (methylene phosphonic acid) (DTPMP) and Diclofenac, exhibit lower climate change (CC) and freshwater ecotoxicity (FET) burdens upon wastewater treatment compared to direct discharge in all country scenarios. Results for Ibuprofen and Acetaminophen (more readily degradable) show that the CC burden depends on the country-specific levels of wastewater treatment. Higher treatment levels lead to lower CC and FET burden compared to direct discharge. WW LCI 2.0 makes it possible to generate complete detailed life cycle inventories and fate analyses for chemicals released to wastewater systems. Our test of the WW LCI 2.0 model with five chemicals illustrates how the model can provide substantially different outcomes, compared to conventional wastewater inventory models, making the inventory dependent upon the atomic composition of the molecules undergoing treatment as well as the country specific wastewater treatment levels. [ABSTRACT FROM AUTHOR]

This study evaluates environmental impacts of an integrated mixed crop-livestock system with a green biorefinery (GBR). System integration included production of feed crops and green biomasses (Sys-I) to meet the demand of a livestock system (Sys-III) and to process green biomasses in a GBR system (Sys-II). Processing of grass-clover to produce feed protein was considered in Sys-II, particularly to substitute the imported soybean meal. Waste generated from the livestock and GBR systems were considered for the conversion to biomethane (Sys-IV). Digestate produced therefrom was assumed to be recirculated back to the farmers' field (Sys-I). A consequential approach of Life Cycle Assessment (LCA) method was used to evaluate the environmental impacts of a combined production of suckler cow calves (SCC) and Pigs, calculated in terms of their live weight (LW). The functional unit (FU) was a basket of two products “1 kg LW -SCC + 1 kg LW -Pigs”, produced at the farm gate. Results obtained per FU were: 19.6 kg CO 2 eq for carbon footprint; 0.11 kg PO 4 eq for eutrophication potential, − 129 MJ eq for non-renewable energy use and − 3.9 comparative toxicity units (CTU e ) for potential freshwater ecotoxicity. Environmental impact, e.g. greenhouse gas (GHG) emission was primarily due to (i) N 2 O emission and diesel consumption within Sys-I, (ii) energy input to Sys-II, III and IV, and (iii) methane emission from Sys-III and Sys-IV. Specifically, integrating GBR with the mixed crop-livestock system contributed 4% of the GHG emissions, whilst its products credited 7% of the total impact. Synergies among the different sub-systems showed positive environmental gains for the selected main products. The main effects of the system integration were in the reductions of GHG emissions, fossil fuel consumption, eutrophication potential and freshwater ecotoxicity, compared to a conventional mixed crop-livestock system, without the biogas conversion facility and the GBR. [ABSTRACT FROM AUTHOR]

This study evaluates the environmental impacts of biorefinery products using consequential (CLCA) and attributional (ALCA) life cycle assessment (LCA) approaches. Within ALCA, economic allocation method was used to distribute impacts among the main products and the coproducts, whereas within the CLCA system expansion was adopted to avoid allocation. The study seeks to answer the questions (i) what is the environmental impacts of process integration?, and (ii) do CLCA and ALCA lead to different conclusions when applied to biorefinery?. Three biorefinery systems were evaluated and compared: a standalone system producing bioethanol from winter wheat-straw (system A), a standalone system producing biobased lactic acid from alfalfa (system B), and an integrated biorefinery system (system C) combining the two standalone systems and producing both bioethanol and lactic acid. The synergy of the integration was the exchange of useful energy necessary for biomass processing in the two standalone systems. The systems were compared against a common reference flow: “1 MJ EtOH + 1 kg LA ”, which was set on the basis of products delivered by the system C. Function of the reference flow was to provide service of both fuel (bioethanol) at 99.9% concentration (wt. basis) and biochemical (biobased lactic acid) in food industries at 90% purity; both products delivered at biorefinery gate. The environmental impacts of interest were global warming potential (GWP 100 ), eutrophication potential (EP), non-renewable energy (NRE) use and the agricultural land occupation (ALO). Regardless of the LCA approach adopted, system C performed better in most of the impact categories than both standalone systems. The process wise contribution to the obtained environmental impacts also showed similar impact pattern in both approaches. The study also highlighted that the recirculation of intermediate materials, e.g. C 5 sugar to boost bioethanol yield and that the use of residual streams in the energy conversion were beneficial for optimizing the system performance. [ABSTRACT FROM AUTHOR]

This work looks at coupling Life cycle assessment (LCA) with a dynamic inventory and multiple criteria decision analysis (MCDA) to improve the validity and reliability of single score results for complex systems. This is done using the case study of a representative Danish single family home over the service life of the building. This case study uses both the established and the coupled MCDA assessment methods to quantify and assess the balance of impacts between the production of mineral wool insulation versus the production of space heat. The use of TOPSIS method for calculating single scores is proposed as an alternative to the ReCiPe single score impact assessment method. Based on the single score impact values obtained from both of these methods, various insulation levels are ranked to determine an ideal insulation level and gauge the effectiveness of environmental impact reduction measures in current Danish building regulations. Using a comparison of the results from the two methods, a preferred choice of impact assessment method is determined. The findings show that if the midpoint impacts for a particular scenario are strongly correlated with a climate change impact indicator, it does not matter which impact assessment is applied. However, for the scenarios where other impact categories vary inversely or independently from the climate change impact indicator, such as with renewable energy production, there is need for a more unconventional method, such as the TOPSIS method, for calculating single score impacts. [ABSTRACT FROM AUTHOR]

Biogas production from animal slurry can provide substantial contributions to reach renewable energy targets, yet due to the low methane potential of slurry, biogas plants depend on the addition of co-substrates to make operations profitable. The environmental performance of three underexploited co-substrates, straw, organic household waste and the solid fraction of separated slurry, were assessed against slurry management without biogas production, using LCA methodology. The analysis showed straw, which would have been left on arable fields, to be an environmentally superior co-substrate. Due to its low nutrient content and high methane potential, straw yields the lowest impacts for eutrophication and the highest climate change and fossil depletion savings. Co-substrates diverted from incineration to biogas production had fewer environmental benefits, due to the loss of energy production, which is then produced from conventional fossil fuels. The scenarios can often provide benefits for one impact category while causing impacts in another. [ABSTRACT FROM AUTHOR]

This study addresses a critical gap in environmental assessments by focusing on petrochemical port operations, an area traditionally overlooked in life cycle assessments (LCAs) of material supply chains. This study investigates various methods of loading for 22 petrochemical products i.e., gas, liquid, container, tanker, and bulk loading; at the biggest petrochemical port in the world situated in the Persian Gulf with a loading capacity of 35 MMt/yr. Twelve scenarios were developed to enhance environmental efficiency based on hotspots defined in LCAs of port loading operations of petrochemicals in their present state. Scenarios 1 through 5 consider electricity savings of 2%–10%, scenarios 6 through 10 consider renewable photovoltaic energy mix of 10%–50%, and scenarios 11 and 12 consider no flaring and rejection of ash waste from ships. To prioritize these scenarios based on environmental efficiency gains, a comprehensive LCA-GRM hybrid model has been introduced. This integrated model combines life cycle assessment and gray relational modeling, providing a robust framework for evaluating and ranking the scenarios. The Best Worst Method (BWM) is implemented for weighing multiple environmental criteria, contributing to informed decision-making. The findings underscore the substantial impact of electricity consumption and gas flaring in petrochemical port operations, prompting the identification of the 'no flaring' scenario (S11) as the most preferred option. Implementing this scenario could lead to significant reductions in climate change impacts (22.14%), ozone formation and human health impacts (16.73%), and photochemical oxidant formation (15.98%). The study's significance lies in emphasizing the environmental implications of port operations and urging policymakers to integrate port impacts into broader supply chain assessments. We advocate for targeted strategies to enhance electricity efficiency and reduce gas flaring in petrochemical ports, aligning with global sustainability goals. The Comprehensive LCA-GRM hybrid approach offers valuable insights for decision-makers involved in the global transportation of goods through ports. [Display omitted] • Fills the gap in petrochemical port assessments, often overlooked in life cycle analyses. • Introduces LCA-GRM hybrid model, prioritizing environmental improving scenarios. • Develops 12 scenarios targeting hotspots, including electricity savings and no flaring. • No flaring S11 reduces GWP (22.14%), OF-HH (16.73%), and POFP (15.98%). • Urges policymakers to integrate port impacts into the supply chain assessment of chemicals. [ABSTRACT FROM AUTHOR]

The Green biorefinery (GBR) is a biorefinery concept that converts fresh biomass into value-added products. The present study combines a Process Flowsheet Simulation (PFS) and Life Cycle Assessment (LCA) to evaluate the technical and environmental performance of different GBR configurations and the cascading utilization of the GBR output. The GBR configurations considered in this study, test alternatives in the three main steps of green-biorefining: fractionation, precipitation, and protein separation. The different cascade utilization alternatives analyse different options for press-pulp utilization, and the LCA results show that the environmental profile of the GBR is highly affected by the utilization of the press-pulp and thus by the choice of conventional product replaced by the press-pulp. Furthermore, scenario analysis of different GBR configurations shows that higher benefits can be achieved by increasing product yields rather than lowering energy consumption. Green biorefining is shown to be an interesting biorefining concept, especially in a Danish context. Biorefining of green biomass is technically feasible and can bring environmental savings, when compared to conventional production methods. However, the savings will be determined by the processing involved in each conversion stage and on the cascade utilization of the different platform products. [ABSTRACT FROM AUTHOR]

Product/Service-Systems (PSS) such as integrated solutions, performance-based contracts or sharing systems are often proposed as means to enable improved environmental sustainability. However, PSS are not necessarily environmentally benign compared to conventional systems. Quantitative environmental performance evaluations of PSS are hence needed. Life cycle assessment (LCA) is a commonly used method for environmental performance evaluation. However, applying LCA in the context of PSS requires specific considerations, which are not sufficiently addressed by current LCA guidelines. In this article, we propose a set of guidelines consisting of six steps, which elaborates the LCA process with respect to the specific consideration for PSS assessment. The guidelines were developed based on identified challenges for the application of LCA on PSS, a review of existing LCAs on PSS case studies, expert consultations, case study applications, and structured user feedback. The use of the guidelines is demonstrated on three exemplifying cases, covering three different scopes for PSS evaluation. By applying the guidelines, the risk of biased results, predictable rebound effects and significant cut-of errors should be reduced. Future work includes evaluating the guidelines through full-scale case applications and further development of dynamic and prospective modelling approaches for assessing systemic consequences and rebound effects. [ABSTRACT FROM AUTHOR]

Green biorefinery (GBR) is a new biorefinery technology for the conversion of fresh biomass to value added products. In the present study, we combined a Process Flowsheet Simulation (PFS) and Life Cycle Assessment (LCA) of a small scale decentralized GBR to screen environmental impact profiles for potential biomass feedstocks for GBR conversion. Furthermore, we carried out hotspot and sensitivity analysis to identify where the largest impacts arise in the biorefining stage in order to provide recommendations and focus points for GBR technology developers. The GBR considered in this study produces a protein-rich feed for monogastric animals and an energy-rich feed from the press pulp and biogas from the GBR residues. The included biomass feedstocks are: alfalfa, grass-clover, festulolium and ryegrass. These biomasses were selected to accommodate variations in central biomass characteristics like: crop yields, rate of fertilizer application, chemical biomass compositions and related potential environmental implications. Among the studied crops, alfalfa provides the best overall environmental performance due to its high yield and low agricultural input demands. Results of the hotspot analysis further identified the coagulation and the drying as the processes that induce most of the environmental impacts in the biorefining stage. Conversion of green biomass for the production of feed and energy could provide environmental benefits compared to the production of conventional feed. However, the GBR technology have still room for optimization in order to further reduce the environmental impacts, across all impact categories, by decreasing energy consumption and increasing conversion efficiency. [ABSTRACT FROM AUTHOR]

The current study aimed at evaluating potential environmental impacts for the production of willow, alfalfa and straw from spring barley as feedstocks for bioenergy or biorefinery systems. A method of Life Cycle Assessment was used to evaluate based on the following impact categories: Global Warming Potential (GWP 100 ), Eutrophication Potential (EP), Non-Renewable Energy (NRE) use, Agricultural Land Occupation (ALO), Potential Freshwater Ecotoxicity (PFWTox) and Soil quality. With regard to the methods, soil organic carbon (SOC) change related to the land occupation was calculated based on the net carbon input to the soil. Freshwater ecotoxicity was calculated using the comparative toxicity units of the active ingredients and their average emission distribution fractions to air and freshwater. Soil quality was based on the change in the SOC stock estimated during the land use transformation and land occupation. Environmental impacts for straw were economically allocated from the impacts obtained for spring barley. The results obtained per ton dry matter showed a lower carbon footprint for willow and alfalfa compared to straw. It was due to higher soil carbon sequestration and lower N 2 O emissions. Likewise, willow and alfalfa had lower EP than straw. Straw had lowest NRE use compared to other biomasses. PFWTox was lower in willow and alfalfa compared to straw. A critical negative effect on soil quality was found with the spring barley production and hence for straw. Based on the energy output to input ratio, willow performed better than other biomasses. On the basis of carbohydrate content of straw, the equivalent dry matter of alfalfa and willow would be requiring higher. The environmental impacts of the selected biomasses in biorefinery therefore would differ based on the conversion efficiency, e.g. of the carbohydrates in the related biorefinery processes. [ABSTRACT FROM AUTHOR]

There has been significant change in the way buildings are constructed and the way building energy performance is evaluated. Focus on solely the use phase of a building is beginning to be replaced by a life-cycle based performance assessment. This study assesses the environmental impact trade-offs between the heat produced to meet a building's space heating load and insulation produced to reduce its space heating load throughout the whole life-cycle of a building. To obtain a more realistic valuation of this tradeoff, a dynamic heat production model, which accounts for political projections regarding change in Danish energy supply was used in the analysis. This novel approach of generating inventory for Life Cycle Assessment (LCA) helped to refine an understanding of optimal insulation levels. The findings of this study discourage the over-insulation of houses connected to the district heating grid, which is potentially promoted at present in Danish regulation. It is further concluded that improvement of the mineral wool insulation production process could allow for greater levels of environmentally beneficial insulation and would also help in reducing the overall environmental burden from insulating buildings. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the potential environmental impacts of producing maize, grass-clover, ryegrass, and straw from winter wheat as biomass feedstocks for biorefinery. The Life Cycle Assessment (LCA) method included the following impact categories: Global Warming Potential (GWP 100 ), Eutrophication Potential (EP), Non-Renewable Energy use (NRE), Potential Fresh Water Ecotoxicity (PFWTox) and Potential Biodiversity Damages (PBD). The results showed that GWP 100 (in kg CO 2 eq, including contribution from soil carbon change) for producing 1 ton of dry matter (t DM) was highest for ryegrass, grass-clover and maize, and lowest for straw. The carbon footprints of ryegrass, grass-clover and maize were affected by including the contribution from soil organic carbon (SOC) changes. Nitrous oxide emissions and emissions related to the production of agro-chemicals (including N-fertilizer) were other hotspots in the carbon footprint. The EP calculated per t DM was highest for grass-clover, ryegrass and maize, and was lowest for straw. NRE use (MJ eq/t DM) was highest for ryegrass, grass-clover and maize and lowest for straw. Major hotspots were diesel use for field operations and agro-chemicals production. The PBD, expressed as Potentially Disappeared Fraction (PDF) showed the highest adverse impact to biodiversity in maize, followed by straw, whereas the results showed relatively lower impact for ryegrass and grass-clover. The PFWTox (CTU e /t DM), at farm level was highest for straw, followed by maize, whereas the values were significantly lower for grass-clover and ryegrass. These variations in ranking of the different biomasses productions using different impact categories for environmental performance showed that it is important to consider a wider range of impact categories for assessing environmental sustainability. [ABSTRACT FROM AUTHOR]

• Different biorefinery platforms based on OFMSW were environmentally scrutinized. • The environmental sustainability of ethanol and butanol production were compared. • Organosolv pretreatment was the most impactful process in all damage categories. • Background emissions of enzyme production dominated climate change and resources. • Simultaneous pretreatment and hydrolysis enhanced the environmental performance. The biorefining of biowastes, specifically the organic fraction of municipal solid waste (OFMSW), into biofuels and high-value products is an energy-demanding process, still immature, and largely dependent on the process configuration and efficiency of employed microorganisms. Such issues might undermine the environmental sustainability of the biorefinery by inducing adverse impacts on human health, ecosystem quality, climate change, and resources, which need to be explored before the process scale-up. Hence, this study was performed as early sustainability guidance to investigate the environmental impacts of different biorefinery platforms for biofuels production from OFMSW. More specifically, three pretreatment methods (i.e., acetone organosolv, acid, and hot water), two hydrolysis treatments (i.e., acidic and enzymatic), and two fermentation alternatives (i.e., ethanolic fermentation and acetone-butanol-ethanol (ABE) fermentation) were investigated. Based on European Commission's Joint Research Center instruction, the environmental impacts were studied using consequential life cycle assessment for the macro-level decision context. The results demonstrated that ABE fermentation scenarios were not environmentally favorable because the avoided impacts from final products were not significant enough to compensate for the induced environmental burdens from acetone pretreatment. On the contrary, the ethanolic fermentation scenarios with either acid or hot water pretreatment outperformed both ABE fermentation and ethanolic fermentation with acetone pretreatment. Based on the results, the scenario including simultaneous dilute acid pretreatment and hydrolysis of OFMSW followed by ethanolic fermentation manifested the best performance in all damage categories, as compared to those including acetone pretreatment or higher consumption of enzymes. Such improvements in this scenario led to the highest net saving of −842 potentially disappeared fraction (PDF)/m2/yr, −249.95 kg CO 2 eq, and −3275.22 MJ primary per ton of OFMSW on ecosystem quality, climate change, and resources, respectively, and the lowest net burden of 1.54 × 10-5 disability-adjusted life years (DALY) per ton of OFMSW on human health. The results of sensitivity analysis on this scenario demonstrated that the substitution of excess heat for marginal heat with fossil origin can considerably decrease impacts on human health. [ABSTRACT FROM AUTHOR]

The past decade has seen a renaissance of urban agriculture in the world's wealthy, northern cities. The practice of producing food in and around cities is championed as a method to reduce environmental impacts of urban food demands (reducing distance from farm to fork – ‘food miles’) whilst conferring a number of ancillary benefits to host cities (runoff attenuation, urban heat island mitigation) and ex-urban environments (carbon sequestration). Previous environmental assessments have found urban agriculture to be more sustainable than conventional agriculture when performed in mild climates, though opposite findings emerge when external energy inputs are significant. In this study we perform an environmental life cycle assessment of six urban farms in Boston and New York City, US producing lettuce and tomatoes, with conventional counterparts across six impact categories. Performance of urban agriculture was system dependent and no farm provided superior performance to conventional for all indicators. High-yield, heated, greenhouse production of tomatoes has potentially higher environmental burdens than conventional methods in terms of climate change (267–369%) and non-renewable resource depletion (108–239%), driven primarily by external energy inputs. Heated lettuce production systems showed similar trends. Low-tech, empty-lot farming appears to hold some advantages in terms of climate change burdens and resource use, though water and land usage was found to be elevated relative to conventional lettuce and tomatoes. Open rooftop farming apparently provides benefits if high yield crops (e.g. tomatoes) are cultivated, otherwise significant capital inputs detrimentally affect environmental performance. In general, the benefits of reduced food miles may be overwhelmed by energy inputs and inefficient use of production inputs. A comparison of urban agriculture and solar panels showed that the latter would confer greater benefits to mitigate climate change per unit area. Thus, urban agriculture may not be the optimal application of space in northern cities to improve urban environmental performance. [ABSTRACT FROM AUTHOR]

Despite their different scopes, both the Life Cycle Assessment (LCA) methodology and the Cradle to Cradle (C2C) Certified™ Product Standard can support companies in the implementation of circular economy strategies. Considering the case of aluminum cans, the objectives of this paper are twofold: (i) to compare the environmental impact associated with different levels of two C2C certification requirements by using LCA; and (ii) to identify the main challenges and drawbacks in the combined use of LCA and C2C for packaging within the circular economy framework. Twenty different scenarios were developed and compared, according to three C2C certification levels, in terms of % renewable energy and % recycled content. The results show that increasing the recycled content provides more improvements to environmental impacts than increasing renewable energy usage. Furthermore, receiving a higher certification level does not necessarily mean environmental burden reduction in LCA sense. From a methodological point of view, the main challenge for LCA is to address the continuous loop of materials and account for the benefits from recycling in a consistent way. Meanwhile for C2C the challenge is to guarantee a proper translation of the C2C principles into the C2C certification program, avoiding burden shifting and to find a balance between the different certification requirements. [ABSTRACT FROM AUTHOR]

Since the turn of the century a growing chorus of researchers has been espousing reduced meat and dairy intake as a partial strategy to transition towards a sustainable food system. Many of these studies have been predicated on a life-cycle assessment (LCA) methodology and though transparent in communicating their work within that framework, it has largely gone unmentioned that LCA involves a number of choices by the assessor and LCA methodology developers that are ultimately subjective. This study uses a consequential LCA of the average Danish diet in comparison to model vegetarian and vegan diets, leveraging the cultural perspectives afforded by the ReCiPe methodology, as starting point to explore the ways that subjectivity influences the LCA process and to test the robustness of the results against these different viewpoints. Mirroring earlier studies, we find vegetarian and vegan diets generally perform better environmentally compared to a standard Danish diet, but that there was minimal difference between the two no-meat options. Results were resilient to varying cultural perspectives applied in the model. LCA methodology, though loaded with value judgments, remains a dependable tool for assessing environmental dietary performance, but is less suited for estimating environmental pressures that are highly dependent on local conditions (e.g. chemical toxicity). [ABSTRACT FROM AUTHOR]

The aim of the current paper is to discuss the sustainability aspect of biorefinery systems with focus on biomass supply chains, processing of biomass feedstocks in biorefinery platforms and sustainability assessment methodologies. From the stand point of sustainability, it is important to optimize the agricultural production system and minimize the related environmental impacts at the farming system level. These impacts are primarily related to agri-chemical inputs and the related undesired environmental emissions and to the repercussions from biomass production. At the same time, the biorefineries need a year-round supply of biomass and about 40–60% of the total operating cost of a typical biorefinery is related to the feedstocks chosen, and thus highlights on the careful prioritization of feedstocks mainly based on their economic and environmental loadings. Regarding the processing in biorefinery platforms, chemical composition of biomasses is important. Biomasses with higher concentrations of cellulose and hemicelluloses compared to lignin are preferred for bioethanol production in the lignocellulosic biorefinery, since the biodegradability of cellulose is higher than lignin. A green biorefinery platform enables the extraction of protein from grasses, producing an important alternative to importing protein sources for food products and animal feed, while also allowing processing of residues to deliver bioethanol. Currently, there are several approaches to integrate biorefinery platforms, which are aimed to enhance their economic and environmental sustainability. Regarding sustainability assessment, the complexities related to the material flows in a biorefinery and the delivery of alternative biobased products means dealing with multiple indicators in the decision-making process to enable comparisons of alternatives. Life Cycle Assessment is regarded as one of the most relevant tools to assess the environmental hotspots in the biomass supply chains, at processing stages and also to support in the prioritization of any specific biobased products and the alternatives delivered from biorefineries. [ABSTRACT FROM AUTHOR]

Abstract: Polar bears (Ursus maritimus) feed mainly on ringed seal (Phoca hispida) and consume large quantities of blubber and consequently have one of the highest tissue concentrations of organohalogen contaminants (OHCs) worldwide. In East Greenland, studies of OHC time trends and organ system health effects, including reproductive, were conducted during 1990–2006. However, it has been difficult to determine the nature of the effects induced by OHC exposures on wild caught polar bears using body burden data and associated changes in reproductive organs and systems. We therefore conducted a risk quotient (RQ) evaluation to more quantitatively evaluate the effect risk on reproduction (embryotoxicity and teratogenicity) based on the critical body residue (CBR) concept and using a physiologically-based pharmacokinetic (PBPK) model. We applied modelling approaches to PCBs, p,p′-DDE, dieldrin, oxychlordane, HCHs, HCB, PBDEs and PFOS in East Greenland polar bears based on known OHC pharmacokinetics and dynamics in laboratory rats (Rattus rattus). The results showed that subcutaneous adipose tissue concentrations of dieldrin (range: 79–1271ngg−1 lw) and PCBs (range: 4128–53923ngg−1 lw) reported in bears in the year 1990 were in the range to elicit possible adverse health effects on reproduction in polar bears in East Greenland (all RQs⩾1). Similar results were found for PCBs (range: 1928–17376ngg−1 lw) and PFOS (range: 104–2840ngg−1 ww) in the year 2000 and for dieldrin (range: 43–640ngg−1 lw), PCBs (range: 3491–13243ngg−1 lw) and PFOS (range: 1332–6160ngg−1 ww) in the year 2006. The concentrations of oxychlordane, DDTs, HCB and HCHs in polar bears resulted in RQs<1 and thus appear less likely to be linked to reproductive effects. Furthermore, sumRQs above 1 suggested risk for OHC additive effects. Thus, previous suggestions of possible adverse health effects in polar bears correlated to OHC exposure are supported by the present study. This study also indicates that PBPK models may be a supportive tool in the evaluation of possible OHC-mediated health effects for Arctic wildlife. [Copyright &y& Elsevier]

Management of the negative environmental impact of pesticides used in paddy fields requires the quantification of the emissions reaching relevant environmental compartments and the determination of the factors that influence such emissions. The present study is the first to develop a simulation model for estimating the fractions emitted to the air (f air), surface water (f sw), and the fractions that leach vertically (f vl) of pesticides applied in paddy fields for life cycle assessments (LCA). The emission quantification methods are based on the properties of the active ingredients of the pesticides and management aspects such as formulations (granular or liquid) and the water-holding period following application. The emission fractions of 37 pesticides used commonly in Japan were estimated using the presented model. A sensitivity analysis was conducted by adjusting parameters applied in the model to reveal their influence on the emission fractions. The parameters influencing f air included the formulation applied, while the water-holding period and waterproofing of the levee influenced f sw regardless of the formulation adopted, suggesting that local management could effectively reduce emissions to surface water. In addition, soil organic carbon content influenced f vl greatly, suggesting considerable regional variation in the emission factor. The developed model is expected to greatly improve the realism of impact assessment of pesticide in LCAs for paddy rice cultivation, considering it fills a gap in the fate model used in LCAs to estimate pesticide emissions to air, surface water, and soil in paddy fields. Unlabelled Image • A new model to estimate emission fractions (EFs) of pesticides from paddy fields • Both pesticide properties and management practices were formulated to calculate EFs. • EFs of pesticides used in Japan were compared with the values based on field datasets. • Water management practices can effectively reduce emissions to surface water. [ABSTRACT FROM AUTHOR]

This study completed a cradle-to-retailer life cycle assessment of Danish export pork and provided a comparative assessment of six after cooling technologies for the supply of pork meat to three markets, Denmark, China and Australia. Nine different pork products delivered to retailers were assessed for fourteen midpoint impact categories. Given the higher efficiency of the Danish pork production system, the relatively small impact of transportation, the relatively large contribution of feed production, and the higher yield of crop production in Denmark, Danish pork production could provide a more sustainable pork supply if issues relating to consumer acceptance of superchilled products and cold chain integrity can be addressed. The human edible protein required (HEPR) in feed to produce 1 kg of human edible protein was over 4 for all supply chains, Denmark had the lowest value of 4.17, 4.27 for Australia and 4.56–5.52 for China, largely due to differences in feed conversion efficiencies. The amount of arable land required to produce 1 kg of human edible pork protein ranged from 38 m2 in Denmark, to 44–51 m2 in China and 161 m2 in Australia, due to large differences in crop yields of the feed ingredients. Pork production is therefore a net consumer of human edible protein and HEPR and arable land use are useful metrics by which to assess food supply chains. The life cycle assessment study was undertaken as part of an industry research project into using new superchilling technologies for exporting Danish pork to distant markets as fresh rather than frozen product, and the HEPR and arable land study was undertaken as part of a PhD on the sustainability of agribusiness value chains. • Superchilling extends the shelf life of "fresh" product and enables exports to distant markets. • Superchilling and transport of pork from Denmark has insignificant impacts, relative to farming. • Human Edible Protein Required (HEPR) was over four for each pork supply chain. • Arable land use ranged from 38 (Denmark) to 161 m2 (Australia) per kilogram of human edible protein. • HEPR and arable land use are useful metrics with which to assess food supply chains. [ABSTRACT FROM AUTHOR]