Techno-economic and Environmental Assessments of SAF from Bioamss:An Review

This review presents a comprehensive techno-economic and life-cycle assessment of sustainable aviation fuel(SAF)production from biomass.The critical need for transitioning towards environmentally sustainable alternatives for liquid fuel and aviation industry is first discussed.Key insights encompass the evolutionary progression of biofuel production from first-generation to second-generation biofuels,with a focus on utilizing non-food sources like woody biomass for enhanced sustainability.Available data from the literature on techno-economic assessments of various SAF production pathways are analyzed including production costs,conversion efficiency,and scalability.Moreover,results of lifecycle assessments associated with different SAF production pathways are presented,providing essential insights for decision-making processes.The challenges of scaling up woody biomass-based SAF production are discussed based on the assessment results,and recommendations are proposed to steer stakeholders towards a greener and more sustainable trajectory for aviation operations.

Lifecycle carbon footprint and cost assessment for coal-to-liquid coupled with carbon capture,storage,and utilization technology in China

Thecoal-to-liquidcoupledwithcarbon capture,utilization,and storage technology has the potential to reduce CO_(2)emissions,but its carbon footprint and cost assessment are still insufficient.In this paper,coal mining to oil production is taken as a life cycle to evaluate the carbon footprint and levelized costs of direct-coal-toliquid and indirect-coal-to-liquid coupled with the carbon capture utilization and storage technology under three scenarios:non capture,process capture,process and public capture throughout the life cycle.The results show that,first,the coupling carbon capture utilization and storage technology can reduce CO_(2)footprint by 28%-57%from 5.91 t CO_(2)/t:oil of direct-coal-to-liquid and 24%-49%from 7.10 t CO_(2)/t:oil of indirect-coal-to-liquid.Next,the levelized cost of direct-coal-to-liquid is 648-1027$/t of oil,whereas that of indirect-coal-to-liquid is 653-1065$/t of oil.When coupled with the carbon capture utilization and storage technology,the levelized cost of direct-coalto-liquid is 285-1364$/t of oil,compared to 1101-9793/t of oil for indirect-coal-to-liquid.Finally,sensitivity analysis shows that CO_(2)transportation distance has the greatest impact on carbon footprint,while coal price and initial investment cost significantly affect the levelized cost ofcoal-to-liquid.

Severe Methodological Deficiencies Associated with Claims of Domestic Livestock Driving Climate Change

Reduction of global livestock numbers and meat consumption have been recommended for climate change mitigation. However, the basic assumptions made to come up with that kind of recommendations reveal severe methodological deficiencies： （1） Carbon footprint, emission intensity, and life-cycle assessments of domestic livestock products reported in scientific literature consistently overlooked the necessity of correcting non CO2 GHG （greenhouse gas） emissions （nitrous oxide and methane） from managed ecosystems for baseline emission scenarios over time and space （pristine ecosystem and/or pre-climate change emissions）; （2） Uncertainties associated with the climate sensitivity of anthropogenic GHG-emissions have been ignored; （3） Inconsistencies in the methodological treatment of land use change （deforestation） in emission intensity calculations （per unit of product） can be detected in the literature; （4） The virtual lack of a discernable livestock signal in global methane distribution and historical methane emission rates has not been acknowledged; theoretical bottom up calculations do not reflect the relative insignificance of livestock-born methane for the global methane budget; （5） Potential substrate induced enhancement of methane breakdown rates have not been taken into consideration. A tremendous over-assessment of potential livestock contribution to climate change is the logical consequence of these important methodological deficiencies which have been inexorably propagated through recent scientific literature.

A DESIGN OPTIMIZATION FRAMEWORK TO ESTIMATE ENVIRONMENTAL IMPACT OF DESIGN DECISIONS IN CONSUMER PRODUCTS

Most products have the potential to negatively impact the environment during all life-cycle stages.However,most environmental impact assessment methods focus on a single product life-cycle and on a specific life-cycle stage.Product design plays a significant role by determining traditional environmental impacts,such as embodied energy of materials,but also by influencing market adoption and production volumes.The main objective of this work is to develop a design optimization framework that estimates the environmental impact of design decisions(e.g.materials choice,etc.)across all life-cycle stages in consumer products.The methodology relies on quality function deployment(QFD),multi-attribute utility theory,non-linear mathematical programming,and life-cycle assess-ment tools to estimate the utility of the design options to the customer,the producer,and the environment.The proposed framework allows designers and other decision makers to select options that are environmentally sound and also aligned with the business objectives.

Carbon Footprint of Transitional Shelters

Extreme weather events, sea level rise, and political disputes linked to climate change are driving masses to leave their homes. Their transitional settlements should be produced in a manner that causes minimum greenhouse gas(GHG) emissions to prevent any further acceleration of climate change and the humanitarian crises it causes. This article presents a study of the carbon footprint and primary energy demand of the construction materials of eight different transitional shelters. The lowest carbon footprints were found from shelter models made from bamboo or timber. The highest emissions were caused by shelters that have either a short service life or that are made from metal-intensive structures. The choice of cladding materials was surprisingly important. The findings were further compared to the overall impacts of each construction project, to national per capita GHG emissions,and to construction costs. Some shelter projects had notable total energy consumption even compared to the annual energy use of industrialized countries. The study concludes that construction materials have an important impact on the carbon footprint of shelters. Comparisons should however be made only between similar functional units. Furthermore, benchmark values and more background data are urgently needed in order to give humanitarian nongovernmental organizations tools for lowering the carbon footprint of their construction operations.