Bioenergy with Carbon Capture, Utilization and Storage (BECCUS) is an important pathway towards net-zero and net-negative emissions. Its mitigation potential depends on net atmospheric CO2 removal into durable storage after accounting for system-wide emissions and removals. However, lifecycle assessment, national greenhouse gas inventories and carbon-market frameworks apply differing accounting approaches, producing divergent mitigation estimates. This study identifies key sources of variability and examines their influence on reported outcomes through a systematic literature review and illustrative calculations for a hypothetical BECCUS system. Depending on the accounting approach, the net system outcome ranges from +422 kt CO2 (net-emitting) to −2,084 kt CO2 (net-reducing), while reported carbon removal ranges from 0 to −1,688 kt CO2. These deviations arise from four interconnected sources: (1) goals and framing, including definitions of concepts, terms and carbon flows; (2) methodological and analytical choices; (3) scope and system boundaries; and (4) baselines and counterfactuals. Governance, monitoring, reporting and verification, and crediting frameworks further shape these sources. Reported outcomes therefore vary primarily because of accounting choices rather than technical performance. The study calls for better alignment of existing methodologies and frameworks so that BECCUS accounting reflects atmospheric outcomes and supports credible climate mitigation.
The container and domestic glass (CDG) industry is one of the most energy-intensive sectors in China. To analyse the life cycle carbon emissions and the potential for carbon reduction of the CDG industry in China, we developed a carbon-emission accounting model based on life cycle assessment (LCA) and conducted an empirical analysis using 2023 as the baseline year. The study evaluates the carbon mitigation potential by adjusting four key variables: applying low-carbon technologies, optimising raw-material composition, modifying the fuel mix, and improving transportation methods. Sensitivity analysis was conducted to identify the critical factors influencing life cycle carbon emissions. Results indicate that the total life cycle CO2 emissions of the CDG industry in 2023 were estimated at 24.0 million tonnes, with raw material sourcing and manufacturing processes contributing over 98% of total emissions. Among all emission sources, fossil fuel consumption and raw material composition are identified as the primary targets for emission reduction. By 2030, the carbon reduction potential of the CDG industry is estimated at 22.85% through increased cullet use, 20.48% through adoption of energy-efficient and low-carbon technologies, 10.65% from optimising the fuel mix, and 0.61% through improvements in transportation methods. Fossil fuel combustion has the most significant impact on life cycle CO2 emissions, followed by changes in cullet usage and the carbon intensity of electricity. These prioritised pathways provide actionable guidance for aligning China's CDG industry with the national dual-carbon strategy.
Accelerated weathering of limestone (AWL) converts CO2 into dissolved bicarbonate by reacting calcium carbonate and water, an alternative to geological storage. This review examines AWL as a branching family spanning the unbuffered concept, buffered AWL (BAWL), and modified routes (potable-water, construction-grade waste limestone, promoter-assisted, utilization-based, ship-based, and electrochemical AWL), grouped into six classes covering reactor configuration, feedstock, dissolution promotion, effluent conditioning, downstream utilization, and electrochemically driven alkalinity generation. AWL has progressed from concept to bench-scale, pilot-scale, modeling, and techno-economic work, but remains pre-commercial, limited by water demand, slow dissolution, reactor size, weak permanence, discharge concerns, and BAWL's calcination cost. Unbuffered AWL is simple but degasses CO2 after discharge. BAWL improves permanence at greater complexity and upstream emissions, relocating rather than resolving the trade-off. Each route targets one bottleneck without resolving the system; cross-study comparison is difficult given differing objectives, water sources, and boundaries. A mass-balance framework separates gross gas-phase capture, dissolved inorganic carbon (DIC) conversion, carbon retained, net stored CO2, and storage duration. The ΔTA/ΔDIC ratio, not capture efficiency alone, governs post-discharge degassing. Carbonic anhydrase raises capture up to 2.2-fold under 20 % CO2 and 4-fold under atmospheric contact, at bench scale. Future progress needs cleaner buffering, industrial-condition pilot testing, and standardised life-cycle accounting.
Land-based Carbon sequestration is projected to play a critical role in India’s long-term low-carbon development strategy. This study aims to (i) identify the data, monitoring and modeling needs for Carbon sequestration programs in forestry and agroforestry systems, (ii) review the research funding agencies and programs, (iii) identify the research priorities and (iv) suggest a strategy to promote research on Carbon sequestration in India. The methodology for the study adopted includes review and assessments of research institutions, programs and projects on Carbon sequestration in India. Carbon trading mechanisms, Carbon sequestration programs, projects, and inventory estimations require Carbon sequestration data and modeling. A number of government departments fund research programs, and there are large research organizations involved, along with many think tanks in Carbon sequestration research. Despite these efforts, there are limitations with respect to the lack of data on land availability, its suitability, and Carbon sequestration rates for the forestry and agroforestry systems for land-based Carbon sequestration projects. Additionally, there is an absence of models and frameworks for mitigation potential assessment. Research priorities identified include: creation of databases and access to the existing datasets, development of region-specific forestry and agroforestry models for the assessment of mitigation potential and the reduction of uncertainties. The strategies include enhanced funding and networking to create accessible databases and the establishment of dedicated programs to develop forestry and agroforestry systems, along with Carbon sequestration rates and institutional arrangements for long-term research, modeling and uncertainty reduction. This could lead to the promotion of robust large-scale Carbon sequestration programs in India.
