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In this paper, a privacy-preserving non-iterative decentralized optimal energy flow for integrated hydrogen-electricity-heat system based on projection method is proposed. A centralized operation model of the integrated hydrogen-electricity-heat system is first established, which is further decomposed into hydrogen, electricity, and heat subproblems, respectively. The proposed projection method transforms the operation space of each subproblem into an equivalent projection space containing whole information of the original operation space. After the operation space transformation, the private information of each system is concealed, thus preserving the privacy of each system. The equivalent projection space of each subsystem constitutes the reformulated convex hull of the integrated energy system. By solving the optimization problem in the reformulated convex hull, the optimal solutions of coupling variables of the integrated energy system are obtained. The optimal solution of coupling variables is used to decompose the integrated energy system and reformulate the subproblem of each subsystem. Optimal energy flow of each subsystem is obtained by solving the reformulated subproblem. Iterations are avoided throughout the solution process of the proposed method, thus addressing various disadvantages of conventional decentralized methods, like poor computational performance and potential non-convergence. The economic performance of the proposed operation model and the computational performance of the proposed projection method were tested on a 6‐6-8 nodes system and a 40‐118-13 nodes system. The low cost and carbon emission of the proposed model and the accuracy, privacy preservation, simplification of model, and less computational time of the proposed method are verified. • A centralized operation model of integrated hydrogen-electricity-heat system is proposed. • Decentralized optimal energy flow is proposed for integrated hydrogen-electricity-heat system. • Privacy-preserving and non-iterative of the proposed projection method are introduced. • Two test systems are provided to verify the validity of the proposed method. [ABSTRACT FROM AUTHOR]

A region-based low-carbon operation analysis method for integrated electricity‑hydrogen-gas systems (IEHGSs) is proposed in this paper. The committed carbon emission operation region (CCE_OR) and the economic CCE_OR (ECCE_OR) are proposed to evaluate the low-carbon feasible space (LCFS) from the low-carbon, secure, and economic perspectives, which provides powerful tools for the low-carbon operation analyses of IEHGSs. Firstly, a coordinated mechanism of carbon flow and hydrogen flow is developed to excavate the low-carbon operation potential of IEHGSs. Then, based on the distributionally robust chance-constrained approach, the concepts and models of CCE_OR and ECCE_OR are defined and formulated considering uncertainties and hydrogen merits. Furthermore, a region model reformulation method is proposed to reformulate the uncertain and non-convex CCE_OR and ECCE_OR models into the deterministic and mixed-integer linear region models. The geometric properties of CCE_OR and ECCE_OR are both theoretically proven, which are the union set of finite convex and bounded polytopes. The united region solution methodology considering the geometric properties of CCE_OR and ECCE_OR is presented to effectively characterize CCE_OR and ECCE_OR. Finally, the numerical results on two test systems verify the effectiveness and applicability of the proposed methods. Simulation results indicate that the proposed methods can improve the LCFS, characterize visual coupling relationships between LCFS and observation variables, and provide comprehensive low-carbon operation information of operation points. • The coordinated mechanism of carbon flow and hydrogen flow is developed to excavate the low-carbon operation potential. • The committed carbon emission operation region (CCE_OR) and the economic CCE_OR (ECCE_OR) are defined and formulated. • The unified region solution methodology considering the geometric properties of CCE_OR and ECCE_OR is established. • The low-carbon feasible space (LCFS) capturing comprehensive operation information is characterized. • The merits and restrictions of zero-carbon characteristics of hydrogen on LCFS are revealed. [ABSTRACT FROM AUTHOR]

Operational flexibility is to depict the ability of a power system in guaranteeing a secure and high-performance system operation, which is essential for distribution systems (DSs) with high renewable energy generation (REG) penetration. However, due to the dispersed integration of energy storage systems and uncertain REGs, the available regulation capability exhibits spatio-temporal coupling. It poses a challenge to quantify flexibility considering multiple locations and time periods. This paper proposes a novel analytical region-based method to characterize the flexibility considering spatio-temporal coupling, where the total dispatch budget and carbon emission constraints are considered to guarantee economic and environmental benefits. Leveraging the basic feasible solution theory, we derive an analytical formulation of the flexibility region, expressed as a set of linear inequalities. Note that no inner or outer approximation techniques are employed in the deduction procedure. The effectiveness and scalability of the proposed method are validated on test systems. Case studies demonstrate that the proposed method enables precise quantification and visualization of operational flexibility for DSs. The derived flexibility region is a closed polyhedron in a high-dimensional space, signifying the maximum ranges of uncertainties that can be accommodated. • A region-based method is developed for quantification and visualization of operational flexibility in distribution systems. • An analytical expression of the flexibility region under spatio-temporal coupling is derived from the dispatch model. • Total dispatch budget and carbon emission constraints are considered in flexibility quantification. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are widely recognized as promising solutions to reduce carbon emissions from the transportation sector. The rapid proliferation of EVs intensifies the interdependency between the power distribution system (PDS) and transportation system (TS). This paper proposes a distributed low-carbon economic dispatch scheme for the integrated power and transportation system (IPTS). Carbon emissions from the TS are quantified by a carbon dioxide calculation model, and the emissions from the PDS are determined by the electricity generation of fossil-fueled generators and the carbon reduction of carbon capture and storage (CCS) devices. An integrated model reformulation method is employed to transform the original non-convex model into a tractable one. Then a distributed solution method based on the spectral penalty parameter based adaptive alternating direction method of multipliers (SPPA-ADMM) is developed to protect the privacy of the PDS and TS. The reformulated model is solved iteratively, and the penalty parameter of the SPPA-ADMM is adjusted adaptively to improve the convergence performance of the method. Numerical results on three test systems demonstrate the effectiveness of the proposed scheme in achieving low-carbon economic dispatch of IPTS. Moreover, case studies validate the superiority of the SPPA-ADMM based distributed solution method in computation performance. • A low-carbon economic dispatch scheme for integrated power and transportation system is proposed. • An integrated model reformulation method is designed to transform the non-convex model into a tractable one. • The SPPA-ADMM based distributed solution method is used to protect the privacy and improve computation efficiency. • Effects of the proliferation of EVs on costs and carbon emissions are discussed in sensitivity analysis. [ABSTRACT FROM AUTHOR]