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This research aims to explore the current evidence on the sustainability of Bioenergy with Carbon Capture and Storage under a life cycle approach and to understand how research on this topic has evolved in the last decade. A systematic literature review was performed, and the main focus was identifying methodological shortcomings and analysing Global Warming Potential results. Forty-seven studies were selected for in-depth revision. Results show that the number of Life Cycle Assessment (LCA) studies on BECCS has increased in the last couple of years and that most of these studies report near-carbon neutral or carbon-negative results for electricity, biofuel energy, and other products. However, in many cases, some aspects have been omitted from the discussion, such as proper accounting of land use impacts, impact allocation procedure, accounting of leakage from storage sites, and impacts related to carbon utilisation. Despite this methodological variability, Global Warming Potential results are mostly carbon-negative and carbon-neutral for both power BECCS and industrial BECCS systems. Consequently, current scientific evidence suggests climate change mitigation benefits from BECCS despite methodological variability. However, it is still insufficient to reach a consensus on the sustainability of this technology as a solution for a global energy transition. It is recommended that further LCA research deals carefully with methodological and product systems variability, which may affect environmental impact results. Moreover, carbon capture approaches with high potential benefits should be further analysed, and the most optimal BECCS typologies should be identified. Finally, additional life cycle impact categories should be reported, along with the assessment of the economic and social dimensions of BECCS. [Display omitted] • Life Cycle Assessment (LCA) of Bioenergy with Carbon Capture and Storage (BECCS) was reviewed. • LCA methodology choices were discussed. • Global Warming Potential ranges between −3.873 and 0.366 kg CO 2 eq per MJ. • Current evidence is insufficient to confirm that BECCS is a sustainable solution for climate change mitigation. [ABSTRACT FROM AUTHOR]

Existing assessments of climate mitigation technologies, like carbon capture utilisation and storage (CCUS), often rely on life cycle assessments (LCA), which are helpful for quantification but may not always be the most complete tools for decision-making. The novel contribution of this study is to provide the first application of a consequential carbon accounting approach, presented as a time-series analysis, to measure the system-wide change in emissions from CCUS linked to CO 2 -enhanced oil recovery. This method includes emissions from marginal oil production, a variable typically excluded in other LCA methods. The method was applied to a hypothetical CCUS project in Mexico to understand critical factors determining whether such an intervention can effectively contribute to emissions reduction in alignment with net-zero goals. Four intervention scenarios were assessed, comparing two distinct CO 2 injection strategies in oil reservoirs (water alternating gas and continuous gas injection) and two energy policy scenarios (current and sustainability). The findings suggest that the energy grid's role in overall emissions is relatively minor, with only a ∼2% difference between the compared scenarios, in contrast, the injection strategy has a significant impact on emissions. Scenarios 1 and 3 report a total change in emissions of −28.39 and −29.87MtCO 2 e, and scenarios 2 and 4 account for −19.63 and −21.22MtCO 2 e, respectively. The results highlight the importance of conducting system-wide analysis and comparing different scenarios to identify the critical components that drive changes in emissions and, therefore, support decision-making and project planning. • Consequential carbon accounting quantifies the system-wide change caused by CCUS. • A time-series provides decision-relevant information on climate change mitigation. • Market-mediated effects are highly relevant for CCUS projects. • CCUS is not consistent with net zero due to as remaining emissions. [ABSTRACT FROM AUTHOR]

The renewal of old bridges is sometimes restricted to avoid the high carbon emissions caused by materials and construction, which however might not be conductive to climate change mitigation due to their insufficient functions. In order to facilitate the optimization of renewal timing and strategy from the perspective of reducing the comprehensive global warming impacts, we put forward the low-carbon bridge renewal decision method referring to the ideas of consequential life cycle assessment (LCA) and dynamic LCA. In the proposed method, a comparative system boundary matching the bridge renewal characteristics is constructed, where the carbon emission reduction owing to the traffic efficiency improvement by functional updating is incorporated as the low-carbon benefits of renewal, and three types of time-dependent factors, i.e., time-dependent characterization factor, trend factors and changes of traffic demands, are introduced to characterize the influence of renewal timing. The proposed method provided guidance for the renewal of Maogang Bridge, the first long-span cable-stayed bridge in Shanghai. Results illustrate that the global warming impacts of renewal construction activities and the low-carbon benefits from functional updating decrease with the renewal timing. For Maogang Bridge, the rapidly increasing traffic demands inevitably advocated renewal in advance, and the reduction of global warming impacts from emission reduction or carbon uptake could be manifested for renewal in advance. Adopting material recycling in the disposal of old bridge helped reconstructing a new bridge while deconstructing the old one in 2019 becoming the finally selected low-carbon renewal strategy, which is expected to reduce 15.04 kt CO 2 e-2019 compared to the essential renewal in 2050 with the landfill disposal method. The robustness of the strategy choice has been justified, given the variations of analytical time horizon, expected emission trends and repair emissions. In this way, the low-carbon renewal decision method could build a quantitative basis for judging the urgency of functional updating and verifying the low-carbon benefits of immediate concrete recycling in up-coming urban renewals. • Low-carbon bridge renewal decision optimizes renewal timing and strategy. • System boundary is expanded for quantifying benefits from functional updating. • Emission trends and time-dependent characterization factors are explored. [ABSTRACT FROM AUTHOR]

• Substitution factors for forest products for the Canadian context were developed. • Substitution factors ranging from 0.51 to 0.91 tC/tC were found. • They will lead to more accurate assessments of the forest GHG mitigation potential. • These factors will help governments to manage forest and fight climate change. Evaluating the climate change mitigation potential of the forest sector requires a holistic approach based on forest carbon (C) sequestration, C storage in harvested wood products (HWP) and substitution on markets. High uncertainty is associated with substitution factors, that express avoided fossil greenhouse gas (GHG) emissions from the use of forest-based products in replacement of GHG-intensive materials and fossil fuels. Few studies have focused on the development of substitution factors in Canada, resulting in the use of unrepresentative generic data. Here, we provide a framework to reduce uncertainties related to substitution factors for primary wood products in a Canadian context. A life cycle assessment framework is used to quantify fossil GHG emissions for a baseline and a wood-intensive scenario. For solid product substitution, we focused on the construction sector and analyzed a range of innovative wood buildings with steel and reinforced concrete as alternative materials. We found non-weighted averages of 0.80 tC/tC for sawnwood and 0.81 tC/tC for panels. For energy substitution, we analyzed cases with different specifications on biomass product, facility type and alternative fossil fuel source in non-residential heat production and biofuel transportation sectors. We found a non-weighted average of 0.80 tC/tC for non-residential heat production and 0.51 tC/tC for biofuel transportation, that can be interpreted as 0.91 tC/tC for heavy fuel oil, 0.69 tC/tC for light fuel oil and 0.68 tC/tC for natural gas substitution. These results provide a benchmark for substitution factors in Canada, to help guide forest management strategies for climate change mitigation. [ABSTRACT FROM AUTHOR]

Temporary carbon storage and substitution benefits of harvested wood products (HWPs) aid in mitigating global warming. However, the extent of this effect remains unclear. Current studies typically rely on a simple summation of the annual carbon sink. This method overlooks the fact that, due to radiative forcing delay, each ton of carbon sequestered has an impact on global warming, which dynamically changes year by year. Such an oversight could lead to an underestimation of HWPs' contribution to global warming mitigation. This study focused on a forestry resource-based city in Northeast China and utilized the Carbon Budget Model for the Canadian Forest Sector (CBM-CFS3) and dynamic life cycle assessment (DLCA) to quantify the dynamic global warming impact (DGWI) of forestry biogenic carbon. The results indicate that: 1) From 2020 to 2120, the maximum DGWI could reach −42.70 Mt CO 2 e. Enhancing the collection and utilization of harvesting residues and promoting products with longer lifespans and higher substitution potential can further increase these benefits. 2) The DLCA method, integrating substitution effects, offers a more precise evaluation of forestry's climate mitigation benefits. Across all scenarios and periods in this study, HWPs' contribution to mitigating global warming, as calculated by the DLCA method, exceeds that estimated by the simple carbon sink summation method by 7.70 %–560.72 %. These findings help to delve deeper into the role of forests in emission reduction and carbon sequestration, providing important references for achieving sustainable forestry management. • Developing and strategically using HWPs positively impacts global warming mitigation. • Method of simply summing up carbon sinks undervalues HWPs' cumulative climate impact. • DLCA method helps assess dynamic global warming impact of forestry biogenic carbon. • Forest management should balance wood production and climate mitigation. [ABSTRACT FROM AUTHOR]

In the quest for carbon neutrality, the cement industry employs various CO 2 mitigation strategies, including material efficiency, cement plant technologies, and clinker-to-cement ratio reductions. This study reviews the past decade's Life Cycle Assessment (LCA) literature on cement production to assess the feasibility of modeling these strategies. Heating energy is the predominant factor in energy consumption, benefiting from energy efficiency measures. Allocation consistently favors cement in evaluations of secondary fuel-related impacts, leading to significant reductions in energy consumption and Greenhouse Gas (GHG) emissions. However, transparency improvements are necessary to clarify the origin and calculation of combustion-related emissions. Challenges arise from limited data availability when assessing grinding energy, especially for high-quality cement aligned with a material efficiency strategy. In our examination of Ground Granulated Blast Furnace Slag (GGBS) as Supplementary Cementitious Materials (SCMs), we have observed that production process variations and allocation assumptions significantly influence LCA models, while highlighting the absence of waste availability consideration in current substitution-focused LCA methods for both secondary fuels and SCMs. • Cement functionalities are generally not described and should be based on strength. • Existing models overlook impacts of increased cement quality due to grinding energy. • Allocation method choice affects climate change impacts of slag-blended cement. • Excluding allocation methods, slag recovery shows climate change impacts variability. • Substantial variability is also found for heating energy for clinkerization. [ABSTRACT FROM AUTHOR]

Bioenergy with carbon capture and storage (BECCS) is regarded as a crucial negative emission technology (NET) in many prospective climate change mitigation scenarios that limit global warming below 2 °C. However, there is still insufficient understanding of the overall life cycle environmental performance of different BECCS configurations. Despite the fact that BECCS entails many technological combinations, the technology is still regarded as a single "black box" technology in most climate scenarios. This study presents a critical review of life cycle assessment (LCA) on a wide range of BECCS options: biomass direct-fired power generation, biomass gasification power generation, bio-hydrogen production, biomass application in industry sectors and other biomass conversion processes, such as pyrolysis and fermentation. It is evident from the review that the biomass direct-fired and gasification power plant with a 100% biomass firing ratio and the gasification-based bio-hydrogen processes have a strong potential to achieve negative emissions. However, the net negative life cycle emissions range widely among studies for each configuration due to variations in technology, LCA methodology and assumptions. Additionally, there is an insufficient assessment of comprehensive environmental impacts for BECCS systems other than GWP, making it still unclear about the trade-offs between the benefit from climate change mitigation and potential negative impacts. Main recommendations for improving LCA on BECCS include developing a generalized guideline and standardization for BECCS LCA, conducting LCAs with comprehensive impact categories, focusing on BECCS configurations being overlooked, considering the impact of land use change and the global warming potential of biomass, and extending LCA in both temporal and spatial dimension. [Display omitted] • Systematically review of life cycle assessment on BECCS systems. • Detailed review on various biomass conversion technologies. • Net negative life cycle emissions range widely among studies. • Insufficient studies of some biomass conversion pathways. • Insufficient studies on multi-environmental environment impact categories. [ABSTRACT FROM AUTHOR]

With emphasis on constructing low-carbon cities, the renovation of old communities highlights the importance of renewing rainwater management facilities. Rain garden is an exceptional Nature-based Solution for rainwater management. When applying them to renovate old communities, the carbon footprint should be considered. This study focused on renovating facilities in the Greater Bay Area and utilized the Energy Expert platform to calculate rain garden carbon footprint with the Life Cycle Assessment. The carbon reduction benefits during the operation were estimated. This study accounting the life cycle carbon footprint of the 5455 m2 rain garden was 1117.42 tCO 2 e. The carbon footprint contribution, from highest to lowest was the end-of-life phase, materials production phase, construction phase, use and maintenance phase. Regarding carbon emission inventory, waste soil landfill, fertilizer acquisition, and waste soil recycling ranked high. Transportation also accounted for a remarkable carbon emission. The rain garden showed great potential for climate change mitigation, with a total and net carbon reduction of 1927.41 and 809.99 tCO 2 e, respectively. To reduce the carbon footprint of the rain garden, we should focus on waste soil treatment and transportation. Recommendations included increasing waste soil recycling, in situ recycling and green transportation. [ABSTRACT FROM AUTHOR]