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Increased use of vehicle electrification to reduce greenhouse gas (GHG) emissions has led to the need for an accurate and comprehensive assessment of the carbon footprint of traction batteries. Unfortunately, there are few lifecycle assessments (LCAs) of commercial lithium-ion batteries available in the literature, and those that are available focus on the cradle-to-gate stage, often with little or no consideration of the use phase. To address this shortfall, we report both cradle-to-gate and use-phase GHG emissions for the 2020 Model Year Ford Explorer plug-in hybrid electric vehicle (PHEV) NMC622 battery. Using primary industry data for battery design and manufacturing, cradle-to-gate emissions are estimated to be 1.38 t CO 2 e (101 kg CO 2 e/kWh), with 78% from materials and parts production and 22% from cell, module, and pack manufacturing. Using mass-induced energy consumptions of 0.6 and 1.6 kWh/(100 km 100 kg) for charge-depleting and -sustaining modes, respectively, the mass-induced use-phase emission of the battery is estimated to be 1.04 t CO 2 e. We show that battery emissions during the cradle-to-gate and use phases are comparable and that both phases need to be considered. A holistic and harmonized LCA approach that includes battery use is required to reduce carbon footprint uncertainties and guide future battery designs.

From a GHG perspective, most LCA studies find incineration (MSWI) to be preferred over landfilling because of high energy recovery offsets. In some studies, however, landfilling results in less greenhouse gases (GHG) emissions than MSWI. We investigated using LCA, the landfill gas (LFG) collection efficiencies and waste composition that led to landfills resulting in less GHG emissions. Then, we explored what theoretical minimum lifetime gas collection efficiencies can be expected when following US LFG regulations. Only landfills with high LFG collection efficiencies (at least 81%) and recovery of methane for energy resulted in less GHG emissions compared to the management of the same waste stream in MSWI; required efficiency increased to 93% without LFG energy recovery. Expected theoretical lifetime LFG collection efficiencies were modeled in the range of 30-80%, with the lower rates associated with landfills having smaller input masses, high decay rates, and low concentrations of nonmethane organic compounds (C NMOC) . Our modeling found that only under a limited combination of conditions (e.g., high C NMOC , high waste input rate, low decay rate) could a landfill expect to achieve a LFG collection efficiency as high as 80%, and that this value falls just under the 81-93% collection efficiency threshold needed for a landfill to result in less GHG emissions than MSWI. When exploring the influence of higher oxidation rates, changing decay rates, varying electricity grids, and inclusion of nonferrous metals recovery offsets the collection effciency range needed increased in nearly all cases; the electricity grid and nonferrous metals offsets had the greatest influence., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Dairy farming is one of the most important sources of greenhouse gas (GHG) emissions in the livestock sector. In order to identify the key emission links and the best emission-reduction strategies for combined dairy farms, this study selected a typical large-scale combined dairy farm in northeast China, constructed a carbon emission model based on the lifecycle assessment concept, and set up different emission reduction scenarios to explore the zero-carbon pathway for combined dairy farms. The results showed that: (1) enteric fermentation and manure management of cows are important sources of carbon emissions from the seeding-integrated dairy farms, accounting for 38.2% and 29.4% of the total, respectively; (2) the seeding-integrated system showed a 10.6% reduction in carbon footprint compared with the non-seeding-integrated system; and (3) scenarios 1–4 reduced carbon emissions by 9%, 20%, 42%, and 61% compared with the baseline scenario, respectively. Therefore, the integrated-farming model is important for the green development of animal husbandry, and as the "net-zero" goal cannot be achieved at present, integrated-farming dairy farms have the potential for further emission reduction. The results of this study provide a theoretical basis for low-carbon milk production. [ABSTRACT FROM AUTHOR]

Food waste (FW) increases with urbanization and population growth, which puts pressure on the treatment system, causing a variety of harmful impacts on the environment. Proper FW treatment is imperative for ecological integrity and public health. Even though FW treatment is an extensively studied topic, the sustainable FW treatment considering holistic-lifecycle-based environmental impacts has rarely been evaluated. This study addresses this gap through a comprehensive analysis of various FW treatment methods, including co-treatment with sewage, anaerobic digestion, incineration, and aerobic composting. The impacts of greenhouse gas (GHG) emission and energy use efficiency are assessed by analyzing diverse FW treatment methods in Shenzhen, China. The study indicates that FW addition to sewage does not adversely affect the current sewage treatment plant, but benefits GHG avoidance and energy recovery. Compared with the other FW treatment methods, FW anaerobic digestion avoids the most GHG emissions with −71.3 kg CO2 eq/FU and recovers the most energy with −223 kWh/FU, followed by FW co-treated with sewage. The energy conversion efficiency of the combined heat and power (CHP) unit greatly affects FW incineration, while energy consumption in incineration and anaerobic digestion (AD) process is relatively minor. Perturbation analysis pinpoints key parameters influencing outcomes, including CHP efficiency, GHG emission factor of local electricity, and chemical oxygen demand (COD) in FW with ratios of −13~−0.942, −0.518~0.22, and −13~1.01, respectively, that should be given special attention. This study sheds light on sustainable FW management strategies, not only in China but also transferrable to regions confronting similar challenges. Advocating ecologically balanced and resource-efficient approaches, the study aligns with broader aims of fostering sustainable development. [ABSTRACT FROM AUTHOR]

The environmental impact of aluminium can be greatly reduced through recycling. However, recycled aluminium ingots are currently used for the fabrication of lower-grade materials (i.e., cascade recycling) and cannot be used for the production of high-purity and high-grade wrought materials, for which demand is expected to increase in the future. Researching and developing upgrade recycling methods for aluminium is therefore urgently needed, where recycled ingots with a lower environmental impact are used for the fabrication of wrought materials. This approach will substantially reduce greenhouse gas (GHG) emissions and ultimately promote a sophisticated resource-recycling society in which aluminium resources can be almost completely recycled. [ABSTRACT FROM AUTHOR]

Shipping corridors act as the arteries of the global economy. The maritime shipping sector is also a major source of greenhouse gas emissions, accounting for 2.9% of the global total. The international nature of the shipping sector, combined with issues surrounding the use of battery technology means that these emissions are considered difficult to eliminate. This work explores the transition to renewable fuels by examining the use of electrofuels (in the form of liquid hydrogen, methane, methanol, ammonia, and Fischer-Tropsch fuel) to decarbonise large container ships from a technical, economic, and environmental perspective. For an equivalent range to current fossil fuel vessels, the cargo capacity of vessels powered by electrofuels decreases by between 3% and 16% depending on the fuel of choice due to the lower energy density compared with conventional marine fuels. If vessel operators are willing to sacrifice range, cargo space can be preserved by downsizing onboard energy storage which necessitates more frequent refuelling. For a realistic green hydrogen cost of €3.5/kg (10.5 €c/kWh) in 2030, the use of electrofuels in the shipping sector results in an increase in the total cost of ownership of between 124% and 731%, with liquid hydrogen in an internal combustion engine being the most expensive and methanol in an internal combustion engine resulting in the lowest cost increase. Despite this, we find that the increased transportation costs of some consumer goods to be relatively small, adding for example less than €3.27 to the cost of a laptop. In general, fuels which do not require cryogenic storage and can be used in internal combustion engines result in the lowest cost increases. For policymakers, reducing the environmental impact of the shipping sector is a key priority. The use of liquid hydrogen, which results in the largest cost increase, offers a 70% reduction in GHG emissions for an electricity carbon intensity of 80 gCO 2e /kWh, which is the greatest reduction of all fuels assessed in this work. A minimum carbon price of €400/tCO 2 is required to allow these fuels to reach parity with conventional shipping operations. To meet European Union emissions reductions targets, electricity with an emissions intensity below 40 gCO 2 e/kWh is required, which suggests that for electrofuels to be truly sustainable, direct connection with a source of renewable electricity is required. • Electrofuels reduce vessel payload by 3% to 16% for an equivalent range • Electrofuels increase total costs by between 124% to 731% depending on the fuel • Fuels which do not require cryogenic storage reduce cost increases • Most expensive technology required for greatest reduction in emissions • Use of electrofuels adds between €0.48 and €3.27 to the price of a laptop [ABSTRACT FROM AUTHOR]

Retrofitting thermal power plants is a valuable opportunity to guide Taiwan's electricity generation towards sustainability. Using an existing power plant nearing decommissioning as a case study, we hypothesized about fuel source options for retrofitting the power plant and compared the resulting impact on lifecycle atmospheric emissions. Our use of the lifecycle assessment (LCA) methodology reflected Taiwan's heavy reliance on the imports and shipping of primary energy sources. We found that after accounting for the contribution of liquefaction and regasification (17%), gas-fired electricity still has significantly lower lifecycle greenhouse gases (GHGs) than coal or fuel oil (FO). In addition, we found that if natural gas (NG) is selected to achieve the greenhouse gas reduction of thermal power, the co-benefit of air pollution reduction can also be achieved at the same time. [ABSTRACT FROM AUTHOR]

Rice, as a main crop, contributes to food security in Asia. However, its by-product, rice straw, poses challenges as it is often disposed of unsustainably. This research investigates the environmental performance of a 1000 m3 rice straw biogas pilot plant in Laguna, Philippines. A lifecycle assessment identified the climate change impact of the biogas system, straw burning and soil incorporation. In addition to GWP100, the global temperature potential's dynamic climate effects were assessed, including integrated radiative forcing and instantaneous temperature effects. The timeframe of the biogenic emission fluxes of rice production is particularly relevant as the sequestered CO 2 during plant growth is partly released as methane and CO 2 , depending on the straw management practices. Straw burning had the highest net emission impact. However, straw incorporation has the highest short-term radiative forcing and temperature increase. The biogas system provided significant short- and long-term GHG emission reduction of up to 68 % when biogas replaced burning or soil incorporation and the use of fossil fuels. Still, considerable uncertainties remain about fugitive methane emissions, handling and post-processing of the digestate. While single GHG emission figures on a GWP100 basis are useful for informing decision-making, this single-metric approach limits understanding of rice production's short- and long-term impacts. Additionally, our assessment emphasises the necessity for governance frameworks that promote sustainable practices in rice farming, as banning rice straw burning may result in less favourable outcomes from soil incorporation, whereas integrating biogas offers a solution benefiting rice-growing communities and global sustainability efforts. • Biogas from rice straw reduces emissions by up to 69 %. • Soil incorporation of straw has highest short-term (20 years) temperature increase. • Assessing more than one metric and timeframe supports more informed decision-making. • Governance frameworks enabling bioenergy integration support SDG 3, 7 and 13. [ABSTRACT FROM AUTHOR]

[Display omitted] • Subsurface hydrogen production technologies were introduced. • The potential of the approach to significantly reduce CO 2 emissions was highlighted. • An overview of major barriers to subsurface technologies was provided. • Finally, the operational challenges faced in subsurface hydrogen production were addressed. Subsurface technologies present an excellent opportunity to produce hydrogen from hydrocarbon resources. It refers to the production of hydrogen directly from underground resources, particularly hydrocarbon resources. This method often involves injecting steam or oxygen into the reservoirs to initiate reactions that produce hydrogen. In some cases, subsurface method can also involve the process of in-situ gasification (ISG), and in-situ combustion (ISC) (also known as subsurface combustion and gasification). The produced hydrogen is extracted from the reservoir, leaving the carbon dioxide and other byproducts underground. This approach could offer a sustainable and carbon-free pathway to produce hydrogen because of reduced CO 2 emissions compared to conventional methods. A comprehensive review of the status and progress of ISC and ISG of hydrocarbon for hydrogen production is presented. The advantages and limitations of the technologies were discussed as well as the underlying reaction mechanism. Techno-economic and lifecycle assessment studies of ISG and ISC are presented. One of the main economic limitations of subsurface hydrogen production is the high cost of building and operating the required infrastructure. However, utilizing pre-existing horizontal wells for air or oxygen injection can significantly reduce the initial infrastructure investment costs. Moreover, the overall process cost of ISG can vary significantly due to various factors, including membrane costs, oxygen production costs and the cost of hydrocarbon. The findings from the environmental evaluation indicate that the primary contributors to greenhouse gas emissions in subsurface technologies are the CO 2 emissions produced during gas combustion for heat generation and the electricity consumed during the gasifying agents' preparation stage. Subsurface methods for producing hydrogen encounter numerous challenges, including choosing the right locations and selecting cost-effective drilling techniques. [ABSTRACT FROM AUTHOR]

Abstract Forest-based bioenergy plays an important role in climate mitigation for limiting global mean temperature increase to below 2 °C. The greenhouse gas (GHG) impact of three forest-based bioenergy systems from the USA, Canada and Spain supplying wood pellets for electricity in the UK were evaluated by conducting lifecycle assessments and forest carbon modelling of the three forest systems. Cumulative emissions were analysed by calculating the forest carbon stock change and net GHG emissions balance of the forest-based bioenergy electricity. The analysis considered both the replacement of the existing electricity mix with bioenergy electricity and forest management with and without bioenergy use. The supply chain emissions and forest carbon balances indicated that GHG emission reductions are possible. However, the cumulative net GHG balance at forest landscape scale revealed that the reduction potential is limited, potentially with no GHG reductions in fast growing forests with shorter rotations, while slow growing forest systems with longer rotations result in greater GHG reductions. This means that the maximum climate benefit is delivered at a different point in time for different forest systems. To evaluate the climate change mitigation potential of forest-based bioenergy it is therefore necessary to consider the management, utilisation and relevant counterfactual of the whole forest and its products. In terms of climate change mitigation potential and minimising possible negative impacts that would require multi-level governance. Highlights • Net GHG balance shows GHG reduction potential of forest bioenergy is limited. • Results are dependent on methods, system boundaries and reference system. • Mitigation potential depends on forest management and whole forest product basket. • Multi-level governance framework require to track wider impacts of forest bioenergy. [ABSTRACT FROM AUTHOR]

• Landfilling was the worst-case scenario in both impact categories in six scenarios. • Alternate methods can treat 60% of total FW and reduce GHG emissions by 70%. • Treating FW with sewage and/or sludge can reduce net GHG emissions of WWTP by ∼50%. • Greater treatment capacity can reach net-zero emissions and net energy recovery. Food waste (FW) being a major solid waste component and of degradable nature is the most challenging to manage and mitigate greenhouse gas emissions (GHEs). Policymakers seek innovative approaches to achieve net zero objectives and recover resources from the FW which requires a comparative and holistic investigation of contemporary treatment methods. This study assessed the lifecycle of six alternative scenarios for reducing net GHEs and energy use potential from FW management in a metropolis, taking Hong Kong as a reference. In both impact categories, the business-as-usual (landfilling) was the worst-case scenario. The combined anaerobic digestion and composting (ADC) technique was ranked best in the global warming impact but was more energy intensive than anaerobic digestion with sludge landfilling (ADL). Incineration ranked second in net GHEs but less favourable for energy recovery from FW alone. The proposed integration of FW and biological wastewater treatment represented an enticing alternative. Integration by co-disposal and treatment with wastewater (CoDT-WW) performed above average in both categories, while anaerobic co-digestion with sewage sludge (AnCoD-SS) ranked fourth. The sensitivity analysis further identified critical parameters inherent to individual scenarios along with biogenic carbon emission and sequestration, revealing their significance on the magnitude of GHEs and scenarios' ranking. Capacity assessment of the studied treatment facilities showed a FW diversion potential of ∼60% while reducing the net GHEs by ∼70% compared to the base-case, indicating potential of net zero carbon emissions and energy footprint by increasing treatment capacity. From this study, policymakers can gain insights and guidelines for low-carbon urban infrastructure development worldwide. [Display omitted] [ABSTRACT FROM AUTHOR]

Converting corncobs into fuel ethanol is different from converting stover because cobs have higher hemicellulose and lower lignin than stover. Current research provides life‐cycle assessments of greenhouse gas (GHG) emissions for stover ethanol but lacks such assessments for corncob ethanol. This study attempts to fill this gap by estimating the lifecycle energy consumption and carbon emissions for corncob ethanol using the GREET (Greenhouses gases, Regulated Emissions, and Energy use in Transportation) model. Our well‐to‐pump (WTP) estimate of fossil fuel consumption is 0.51–0.84 MJ MJ−1 of ethanol produced. The estimated GHG emissions are 39.44–49.97 gCO2eq/MJ of ethanol; about 90% is attributed to the conversion process. If glucose and xylose are co‐fermented, it requires 10% less energy and emits about 20% fewer GHGs from well to pump. The estimates are sensitive to the variations in corn yield and hydropower supply. Pump‐to‐wheel emissions are also assessed for representative vehicles with spark‐ignition engines in China. We find that hybrid and plug‐in hybrid electric vehicles have 18–20% lower emissions than internal combustion engine vehicles (ICEVs), and flexible‐fuel vehicles using E85 have similar WTP emissions to ICEVs. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Achieving low operational energy (OE) consumption in high heating and cooling situations typically leads to well-insulated buildings. In those cases, embodied energy (EE) can exceed the operational share. Specific literature refers mostly to heating-dominated residential buildings, with a clear focus on European, Asian, and North American countries. Information on embodied impacts of buildings other regions is virtually inexistent. This paper aims at estimating lifecycle energy and greenhouse gases (GHG) emissions of selected design versions of a photovoltaic-powered Living Lab in Campinas, Brazil; and at finding the embodied-to-operational impact ratios as well as the main contributors to those overall impacts. Homer Energy software supported sizing of photovoltaic (PV) arrays for ten energy compensation scenarios to, based on simulated OE, determine the feasibility threshold for onsite generation admitted by the building design. We then modelled lifecycle energy and GHG emissions for the net zero (NZE) and threshold energy positive (E + ) versions of the case study design. The Cumulative Energy Demand (CED) and the CML 2001 v.2.05 methods supported embodied energy and global warming potential (GWP) calculations in SimaPro 7.3. The E + building compensates its OE plus non-renewable energy embodied in building products. Steel frame and partitions were the largest contributors to EEG in building products, whilst the insulated façade panels and PV array performed key energy performance roles at comparatively lower embodied impacts. Shifting from NZE towards E + status discretely increased the embodied-to-operational energy ratio (EE:OE), at similar embodied-to-operational GHG emissions (EG:OG) ratios. Pre-use share of lifecycle CED was slightly surpassed by the operational one, whilst responding for 60% of lifecycle GWP. Material replacement over the reference service life contributed significantly to operational impacts. EOL treatment had negligible effect on lifecycle impacts. EE more than tripled OE and embodied emissions exceeded OG by a factor of seven. EEG prominence confirms the crucial need for a harmonized calculation approach, as experienced for operational stage accountancy over the recent years. We acknowledge the high uncertainties involved in using simulated over measured OE consumption and in using foreign LCI databases. The former limitation can be solved by monitoring operational performance upon projects completion. This study offers practical and detailed reference for LCA practitioners in all countries facing the latter challenge, which will persist until integrated national LCI databases finally become available. [ABSTRACT FROM AUTHOR]

This paper statistically quantifies the lifecycle greenhouse gas (GHG) emissions from six distinct reactor-based (boiling water reactor (BWR), pressurized water reactor (PWR), light water reactor (LWR), heavy-water-moderated reactor (HWR), gas-cooled reactor (GCR), fast breeder reactor (FBR)) nuclear power generation systems by following a two-step approach that included (a) performing a review of the lifecycle assessment (LCA) studies on the reactor-based nuclear power generation systems; and (b) statistically evaluating the lifecycle GHG emissions (expressed in grams of carbon dioxide equivalent per kilowatt hour, gCO2e/kWh) for each of the reactor-based nuclear power generation systems to assess the role of different types of nuclear reactors in the reduction of the lifecycle GHG emissions. Additionally, this study quantified the impacts of fuel enrichment methods (centrifuge, gaseous diffusion) on GHG emissions. The mean lifecycle GHG emissions resulting from the use of BWR (sample size, N = 15), PWR (N = 21), LWR (N = 7), HWR (N = 3), GCR (N = 1), and FBR (N = 2) in nuclear power generation systems are 14.52 gCO2e/kWh, 11.87 gCO2e/kWh, 20.5 gCO2e/kWh, 28.2 gCO2e/kWh, 8.35 gCO2e/kWh, and 6.26 gCO2e/kWh, respectively. The FBR nuclear power generation systems produced the minimum lifecycle GHGs. The centrifuge enrichment method produced lower GHG emissions than the gaseous diffusion enrichment method. [ABSTRACT FROM AUTHOR]

The livestock sector is under considerable pressure to reduce greenhouse gas (GHG) emissions. Repeated measurements of emissions over multiple years will indicate whether the industry is on course to successfully meet emission reduction targets. Furthermore, repeated analyses of individual farm emissions over different timeframes allow for a more representative measure of the carbon footprint (CF) of an agricultural product, as one sampling period can vary substantially from another due to multiple stochastic variables. To explore this, a CF was measured for 15 livestock enterprises that had been assessed three years previously. The aims of the research were to: (1) objectively compare CFs between sampling periods; (2) assess the relationship between enterprise CF and input efficiency; (3) use scenario analyses to determine potential mitigation measures. Overall, no significant difference was detected in beef and lamb enterprise CFs between the two sampling periods. However, when all observations were pooled together, the lowest-emitters were found to have more efficient systems with higher productivity with lower maintenance “overheads”, compared with their higher-emitting counterparts. Of significance, scenario analyses revealed that the CF of beef and lamb could be reduced by 15% and 30.5%, respectively, if all enterprises replicated the efficiency levels of the least-emitting producers. Encouraging and implementing efficiency gains therefore offer the livestock industry an achievable method of considerably reducing its contribution to GHG emissions. [ABSTRACT FROM AUTHOR]

An increased interest for separate collection of household food waste in Sweden has led to development of a number of different collection-systems – each with their particular benefits and drawbacks. In the present study, two systems for collection of food waste in households were compared; (a) use of food waste disposers (FWD) in kitchen sinks and (b) collection of food waste in paper bags for further treatment. The comparison was made in relation to greenhouse gas emissions as well as primary energy utilization. In both cases, collected food waste was treated through anaerobic digestion and digestate was used as fertilizer on farmland. Systems emissions of greenhouse gases from collection and treatment of 1 ton of food waste (dry matter), are according to the performed assessment lower from the FWD-system compared to the reference system (−990 and −770 kg CO 2 -eq./ton food waste dry matter respectively). The main reasons are a higher substitution of mineral nitrogen fertilizer followed by a higher substitution of diesel. Performed uncertainty analyses state that results are robust, but that decreasing losses of organic matter in pre-treatment of food waste collected in paper bags, as well as increased losses of organic matter and nutrients from the FWD-system could change the hierarchy in relation to greenhouse gas emissions. Owing to a higher use of electricity in the FWD-system, the paper bag collection system was preferable in relation to primary energy utilization. Due to the many questions still remaining regarding the impacts of an increased amount of nutrients and organic matter to the sewage system through an increased use of FWD, the later treatment of effluent from the FWD-system, as well as treatment of wastewater from kitchen sinks in the reference system, was not included in the assessment. In future work, these aspects would be of relevance to monitor. [ABSTRACT FROM AUTHOR]

Perovskite (PK)-based tandem solar cells (TSCs) are an emergent photovoltaic (PV) technology with potential to surpass the Shockley–Queisser theoretical limit of efficiency (η) of single-junction (SJ) silicon solar cells. The promising efficiency of PK/Si-TSCs > 29% indicates the potential of next-generation PV technology as efficiencies of approximately 45% could be achieved through complete optimization of the optical and electrical parameters of PK/Si-TSCs. To establish a technological roadmap for future research, it is necessary to review and discuss the future technological advancements and economic prospects concerning PK-based TSCs, as well as determine the economic impact. Here, the merits and demerits of different configurations of PK-based-TSCs are reviewed to determine the best design strategies for optical/electrical connection and light distribution between the top and bottom sub-cells. The current status and recent advances in both two- and four-terminal PK/Si tandems are discussed, along with the technological approaches employed and the maximum η achieved. Additionally, the three-terminal tandem configuration and how it solves the current mismatch in the two-terminal configuration and the optical losses in four-terminal architecture are summarized. Future technological developments and economic prospects of PK-based TSCs are discussed. The PK/Si heterojunction (SHJ)-TSC-based PVs were found to cause similar or less environmental impact than c-Si PVs, along with the possibility of further improving the environmental outcome by replacing the SHJ with SJ-Si (p-n homojunction) bottom sub-cell. Additionally, by further reducing the levelized cost of electricity, TSCs fabricated with mc-Si are likely to have strong economic prospects. • Technological advancements and economic prospects concerning perovskite-based tandem cells have been discussed. • Tandem solar cells fabricated with mc-Si bottom sub-cell have strong economic prospects. • Perovskite/SHJ tandem cells cause similar or less environmental impact than c-Si cells. • Three-terminal tandem design overcomes the limitation of the top sub-cell bandgap, delivering a high energy yield. [ABSTRACT FROM AUTHOR]

Abstract: A variety of researchers have constructed and presented lifecycle assessments of the microalgae-to-biofuel process, however, inconsistencies in system boundary definitions and high-level process modeling have led to a wide range of results. This study integrates engineering process models validated through experimental and modeling research to perform an environmental assessment of four microalgae-to-biofuel production scenarios leveraging the Argonne National Laboratory GREET model. The baseline scenario consists of a down flow open pond growth system, three phase de-watering step (settling, dissolved air flotation, and a centrifuge), hexane extraction and nutrient recovery using anaerobic digestion. The net energy ratio (NER), defined as energy consumed over the produced energy, and greenhouse gases (GHG) for the baseline scenario are 0.7MJMJ−1 and −41.7gCO2-eq MJ−1 respectively. Three alternative scenarios are also evaluated: 1) Improved microalgal productivity, 2) supercritical CO2 extraction, and 3) no nutrient recycle. This research shows that supercritical CO2 extraction is neither currently energetically- nor environmentally favorable and that nutrient recycle plays an integral role in achieving favorable NER and GHGs. The study highlights on the systems level, two findings related to the NER; 1) the NER is minimally impacted with increased productivity and 2) increasing microalgae lipid content detrimentally affects the NER which is attributed to the reduction in the total energy that can be captured by the anaerobic digester. [Copyright &y& Elsevier]

In this study, a stochastic multistage lifecycle programming model (SMLP) for supporting the management of power systems and the associated economic and environmental risks is proposed. A two-fold objective is pursued. First, information on lifecycle GHG emissions from 10 forms of power generation technologies is comprehensively reviewed and characterized. Second, optimized pathways for the electricity system transition with specific consideration of lifecycle GHG emissions and lifecycle costs are identified. This work presents methodological advances in integrating the lifecycle concept with a power system optimization model, which can enhance the robustness of the resulting decision support. A case study for the Province of Saskatchewan is undertaken, where various uncertainties and risks are quantified and trade-offs among a number of system objectives/criteria are analyzed. According to the review, the lowest average emission per unit power generation is hydropower (12.8 g CO 2 -eq/kWh), closely followed by offshore wind power (14.6 g CO 2 -eq/kWh) and on-shore wind power (15.3 g CO 2 -eq/kWh). According to the modeling results, on-shore wind power is likely to become the dominant form of power generation in Saskatchewan by the end of the planning horizon; import power would play a big part in securing the province's electricity supply in the future. It is expected that the modeling results can help support the formulation of regional energy and relevant socio-economic and environmental policies. • A stochastic multistage lifecycle programming model (SMLP) is developed. • Lifecycle GHG emissions of various technologies are considered in power system optimization. • Trade-offs among a number of system objectives/criteria are revealed. • Optimized pathways for the electricity system transition for Saskatchewan, Canada are identified. [ABSTRACT FROM AUTHOR]

In the 1990s, attention was focused on saving energy and water with the aim of reducing production costs. Since the turn of this century, problems relating to the management of greenhouse gases have gradually assumed greater importance. Research has highlighted the problems that may arise regarding energy consumption in an Italian dairy chain. Using life-cycle assessment methods, the main steps along the production chain have been identified: breeding, dairy, and food store (FS). Our analysis shows that the different issues involved are often not easily reconcilable. Energy data need to undergo a careful and specific normalization process when dealing with specific data on different parameters (kWh/tmilk, kWh/tmilk processed, kWh/mstore²). This study examined a variety of production cases (2 farms, 2 dairies, and 2 FSs) located in Lombardy, northern Italy, and electric and thermal energy consumption and carbon dioxide emissions were evaluated. A total of 2.8 kgCO2/kgcheese carbon dioxide emissions relating to the production process were recorded (39% breeding, 40% dairy, 1% FS). Further studies are needed in order to provide consumers with more precise and correct information (carbon labeling or green label). This may become an important element in consumer choice. [ABSTRACT FROM AUTHOR]

A lifecycle model was established to explore the efficiency, economy, and greenhouse gas emissions of a non-phase-transition drying pyrolysis and mass conversion technology, based on the principle of lifecycle assessment. The evaluation scope included straw collection and transportation, drying and crushing, biomass pyrolysis, charcoal processing, and waste heat utilization. The results show that the energy output/input ratio for non-phase-transition drying pyrolysis was 20.43, and the energy efficiency was high. The pure profit from treating wet straw was USD 45.32 per ton, the profit margin of sales was 52.11%, and the economic benefit was high. The equivalent emission of CO2 was 34.10 g·MJ−1, demonstrating high environmental benefits. Therefore, non-phase-transition drying pyrolysis and mass conversion technology is a potential biomass utilization technology with energy, economic, and ecological benefits. [ABSTRACT FROM AUTHOR]

• Developed algorithms that quantify the environmental impacts of pavements. • Provided a methodical, descriptive, and flexible framework for LCA. • Assessed merits of PCP in reducing embodied energy and carbon footprint. • Evaluated the capital cost benefits of PCP over PCCP. • Adjudged construction of PCP as a promising eco-friendly and sustainable strategy. This study provided a systematic lifecycle assessment (LCA) methodology that was used to quantify the total embodied energy and greenhouse gas (GHG) emissions involved in construction of a new pavement. Furthermore, a comparative LCA was performed to adjudge the benefits offered by pervious concrete pavement (PCP) over Portland cement concrete pavement (PCCP) for different mixing procedures, and distinct base layers. The system boundaries included the following phases of pavement LCA: raw material production, transportation, and pavement construction. The total embodied energy and GHG emissions were quantified for a functional unit of 1 km single lane road, 3.5 m wide, and 0.35 m thickness. The relative contribution of each component to energy consumption and GHG emissions was estimated and the variability of LCA model parameters was understood using sensitivity analysis. The results dictated that the total embodied energy and GHG emissions in PCP with aggregate base layer were reduced by up to 3% and 2.7%, respectively, compared to that of PCCP with similar configuration. Further, a capital cost analysis was conducted due to non-availability of maintenance and end-of-life data, which indicated that PCP is almost 1.21% costlier than PCCP for RMC mixing, and 4.13% cheaper for in-situ mixing. The conceptual approach developed in this study provided a generalized methodical framework that could be used to assess the environmental credibility of pavement systems for site-specific conditions. [ABSTRACT FROM AUTHOR]

This article presents the abstract of the paper Life Cycle Analysis of Wheat and Barley Crops for Bioethanol Production in Spain, which appeared in the 2005 issue of the International Journal of Agricultural Resources, Governance and Ecology. A Life Cycle Assessment (LCA) of the agricultural production of wheat and barley grain to be used as a raw material for bioethanol production in Spain is performed. The objective of the work presented is to compare the environmental impact of the production of these two alternative raw materials for the production of bioethanol. This study is carried out in the frame of a higher scope study, an LCA of alternative fuels for transport launched by the Spanish Ministry of Environment. Results show that wheat cultivation has a smaller impact in every impact category with the exception of the global warming category. Considering only the agricultural production stage, it seems that wheat is more recommendable than barley for bioethanol production, but given that the main objective in the biofuels introduction is the fulfillment of the greenhouse gases reduction commitments, barley is a better option than wheat.