Research On Evaluating Methods For Carbon Emissions Of Concrete Dams Based On Life Cycle Assessment

Currently, many hydraulic projects will be constructed in the next ten yearsto respond to the increasing demand for clean energy and governmentalcommitment of carbon reduction. In the previous studies, more attention is paidon the evaluation of emissions from reservoirs and the carbon abatements fromhydraulic electricity, instead of the emissions from dam constructions. Alongwith the rapid development of concrete dam projects, the emissions fromconstructing concrete dams are worth evaluating. To meet the need of lowcarbon development, there is a need to study the evaluating methods for carbonemissions of concrete dams, analyzing emission factors, comparing differentdam construction methods and realizing the processes management of carbonemissions.On the perspectives of life cycle, the boundary of the research has beendefined as the phases of material production, transportation, construction,operation and maintenance. The emission factors are obtained by analyzing thedifferent construction methods and investigating the on-site data. According tothese factors, a life cycle inventory model has been estabilished. Then this studyhas built the evaluating model for carbon emissions of concrete dams, integratedby the discrete event simulation (DES). During construction processes, theemissions are evaluated by the real operating and idling time.The reliability andnecessity of the DES model are demonstrated by comparing the simulation andactural results.To test the established model, many dam projects (e.g. Hengshan, Xiluodu)are applied. Data have been collected by investigating the reports, material lists,on-site video, interview and questionnaire.Through comparing Rock-FilledConcrete (RFC) and Conventional Concrete (Conv.C), the main phase of carbonemissions has been defined, demonstrating the model estabilished could be usedin analyzing different construction methods. Then14cases are analyzed to getthe comparison results among RFC, Conv.C and Roller Compacted Concrete(RCC), showing the RFC is a more environmental construction method. The most effective way to improve the carbon performance of construction processesis to lower the idling time and promote the operation efficiency. This study hasproposed the evaluation methods of carbon emission, cost and scheduleperformance.The performance of these three variables has been analyzed byusing correlation analysis and typical analysis. The results demonstrate theemission factor can be a typical index, which could reflect the performance ofthe other two factors. The evaluating model has been confirmed by realizing theprocesses management of carbon emissions.Lastly, this study has further implied the ways of how decision makerscould reduce the carbon emissions of concrete dams on the perspectives ofadopting low carbon dam construction technologies, optimizing constructionprocesses, recycling abundant materials and enhancing the temperature controlbased on the case studies.