Integrated Electricity-Heat-Gas Systems: Techno-Economic Modelling, Optimization and Application to Multi-Energy Districts

Multi-energy systems (MES) can optimally deploy their internal operational flexibility to use combinations of different energy vectors to meet the needs of end-users and potentially support the wider system. Key relevant applications of MES are multi-energy districts (MEDs) with, for example, integrated electricity and gas distribution and district heating networks. Simulation and optimization of MEDs is a grand challenge requiring sophisticated techno-economic tools that are capable of modelling buildings and distributed energy resources (DER) across multi-energy networks. This paper provides a tutorial-like overview of the state-of-the-art concepts for technoeconomic modelling and optimization of integrated electricity heat-gas systems in flexible MEDs, also considering operational uncertainty and multiple grid support services. Relevant mixed integer linear programming (MILP) formulations for two-stage stochastic scheduling of buildings and DER, iteratively softcoupled to nonlinear network models, are then presented as the basis of a practical network-constrained MED energy management tool developed in several projects. The concepts presented are demonstrated through real-world applications based on the University of Manchester MED case study, whose details are also provided as a testbed for future research.