Optimal operation for integrated energy system considering thermal inertia of district heating network and buildings

Wind power integration could be restricted by inflexible operation of combined heat and power (CHP) units due to the strong linkage between power generation and heating supply in winter. Utilization of the heat storage capacity of existing district heating network (DHN) is a cost-effective measure to enhance power system operational flexibility to accommodate large amounts of variable wind power. In this paper, transmission-constrained unit commitment (UC) with combined electricity and district heating networks (UC-CEHN) is formulated with a linear DHN model to coordinate short-term operation of electric power and district heating systems. The heat storage capacity of the DHN is modeled by capturing the quasi-dynamics of pipeline temperature. Both deterministic and robust models are developed to incorporate UC with the linear DHN model. Case studies are carried out for two test systems to show the potential benefits of the proposed method in terms of wind power integration and efficient operation.

Transmission-Constrained Unit Commitment Considering Combined Electricity and District Heating Networks

Modelling, assessment and Sankey diagrams of integrated electricity-heat-gas networks in multi-vector district energy systems

Integrated energy systems

This article proposes a distributed multi-period multi-energy operational model for the multi-carrier energy system. In this model, energy hubs function as distributed decision-makers and feature the synergistic interactions of generation, delivery, and consumption of coupled electrical, heating, and natural gas energy networks. The multi-period multi-energy scheduling is a challenging optimization problem due to its strong couplings and inherent nonconvexities within the multi-energy networks. The original problem is thus reformulated as a mixed integer second-order cone programming (MISOCP) and subsequently solved with a sequential second-order cone programming (SOCP) approach to guarantee a satisfactory convergence performance. Furthermore, a fully-distributed consensus-based alternating direction method of multipliers (ADMM) approach with only neighboring information exchange required is developed to optimize the multi-energy flows while considering the local energy-autonomy of heterogeneous energy hubs. The proposed methodology is performed and benchmarked on a four-hub urban multi-energy system over a 24 hourly scheduling periods. Simulation results demonstrated the superiority of the proposed scheme in system operational economy and renewable energy utilization, and also verify the effectiveness of the proposed distributed approach.

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Distributed Multi-Energy Operation of Coupled Electricity, Heating, and Natural Gas Networks

Combined analysis of electricity and heat networks

Optimal coordinated operation of a multi-energy community considering interactions between energy storage and conversion devices

A blockchain consensus mechanism that uses Proof of Solution to optimize energy dispatch and trading

Single-ion polymer electrolytes have received considerable attention in the development of high-safety and high-energy-density lithium metal batteries due to their high lithium ion transference number, good interfacial compatibility with lithium metal anode, and suppression of lithium dendrite benefits from the immobilization of anions. In this work, we develop a novel single-ion polymer composite electrolyte (SIPCE) by an in situ photoinitiated polymerization of single-ion polymer monomers into porous metal–organic frameworks (MOF)/polymer electrospun fibrous membrane. Experimental results demonstrate that the received SIPCE-MOF exhibits a high lithium ion transference number of 0.80, a wide electrochemical stability window up to 5.68 V, and the remarkable ionic conductivity of 1.14 × 10–5 and 2.23 × 10–5 S cm–1 at 30 and 60 °C, respectively. In addition, the lithium symmetrical battery with such SIPCE-MOF shows a polarization voltage of 120 mV at a current density of 2 mA cm–2 and a stable cycling time of more than 2200 h, implying the excellent long-term lithium plating/stripping performance. As a result, the solid-state LiFePO4/SIPCE-MOF/Li battery achieves an unparalleled rate performance (105 mAh g–1 at 2 C) and maintains 98.3% of its initial capacity after 120 cycles with a superhigh Coulombic efficiency of 99% at 0.5 C. These excellent properties provide great potential for the application of single-ion polymer composite electrolytes in solid-state lithium metal batteries. 

A Single-Ion Polymer Composite Electrolyte Via In Situ Polymerization of Electrolyte Monomers into a Porous MOF-Based Fibrous Membrane for Lithium Metal Batteries

Xuezhi Liu

Papers

Combined analysis of electricity and heat networks

Modelling, assessment and Sankey diagrams of integrated electricity-heat-gas networks in multi-vector district energy systems

Optimal coordinated operation of a multi-energy community considering interactions between energy storage and conversion devices

A blockchain consensus mechanism that uses Proof of Solution to optimize energy dispatch and trading

A Single-Ion Polymer Composite Electrolyte Via In Situ Polymerization of Electrolyte Monomers into a Porous MOF-Based Fibrous Membrane for Lithium Metal Batteries