Research On Optimization And Evaluation Of Integrated Urban Energy Systems

Within the background of smart and low-carbon energy transformation worldwide,the urban energy supply combines multi-energy sectors,as well as cyber-physical information,which leads to the traditional supply-side oriented and single flow urban energy system out of date.In the meantime,the next-generation-integrated urbanenergy systems can fulfill the electricity,cooling,heating and gas demands simultaneously in a real-time manner.Starting from optimizing the structure of urban energy,this thesis focuses on the topic of optimization and evaluation of integrated urban energy systems.The models of integrated urban energy systems are established via mathematical programming methods systematically.Comprehensive analysis of integrated urban energy system optimization and evaluation methods is conducted exploring the best system design and dispatch strategies.The main content of this thesis is as follows:At first,the research boundary is defined,and relevant research background and current progress worldwide are reviewed.On this basis,a "bottom-up" integrated urban energy system model is established by the modular strategy including generally applicable devices.Meanwhile,the commonly used objective functions and evaluation indexes are summarized.Secondly,the multi-objective optimization of the proposed system modelling is investigated to evaluate the trade-offs between different objectives and the corresponding impacts on the system design.Different posterior decision-making methods are compared in order to determine the most suitable multi-objective optimization and decision-making method.Meanwhile,a multi-criteria evaluation method is proposed to evaluate system performance comprehensively.The synchronization of multi-objective optimization and multi-criteria evaluation is further explored.Afterward,the Cooperative Game Theory is applied to ensure all buildings within a neighborhood-level energy network share the benefit in a fair manner.Furthermore,a hierarchical approach is proposed to deal with the trade-off between the modelling resolution and computational cost for optimizing an even larger scale integrated energy network considering multiple uncertainties.Finally,a "system value" approach is proposed to deal with technology evaluation issue,which evaluates individual technology from a systematic perspective.The structural uncertainty is introduced accordingly,and a "portfolio constraints" method is proposed to analyze the contribution of each technology for the whole system design considering multiple objectives.This systematic evaluation approach could provide a novel perspective for decision-maker when comparing different technologies.Overall,this thesis conducts research on optimization and evaluation of integrated energy systems from multiple perspectives,the research could be a theoretical basis and provide a tool for urban energy planning and sustainability.