Combined analysis of coupled energy networks
Energy supply systems such as the electricity, natural gas, district heating and cooling networks are typically designed and operated independently of each other. The increasing use of technologies such as combined heat and power units, gas turbines, heat pumps and recently, power to gas systems are increasing the links between energy systems introducing technical and economic interactions. There is a significant interest from academics, industry and policy makers in different parts of the world to identify and realise the opportunities of integrating energy networks while avoiding any undesirable impacts. Analysis of the interdependencies between different energy systems requires powerful software models and analysis tools. However, there are no commercial tools available to date. The aim of this research is to develop a model for the combined steady state simulation and operation planning of integrated energy supply systems. As part of this thesis, three key components of the model were developed i.e. a) Optimal power dispatch of an integrated energy system: A real case study was used to demonstrate the economic benefits of considering the interactions between different energy systems in their design and operation planning. b) Simultaneous steady state analysis of coupled energy networks: An example of a coupled electricity, gas, district heating and district cooling network system was used to illustrate the formulation of equations and the iterative solution method. A case study was carried out to demonstrate the application of the method for integrated energy network analysis. c) Steady state analysis of gas networks with the distributed injection of alternative gases: A case study was carried out to demonstrate the impact of alternative gas injections on the pressure delivery and gas quality in the network.