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

The widespread use of decentralised multi-energy supply solutions such as gas-fired Combined Heat and Power (CHP), heat pumps, gas boilers, and so forth is more and more increasing the linkages between electricity, heat and gas distribution networks. However, there is currently no model able to model the three networks in an integrated manner and with a suitable level of detail for operational purposes. A multi-temporal simulation model, which has been implemented in a relevant MATLAB-Excel VBA tool, is presented in this paper to carry out integrated analysis of electricity, heat and gas distribution networks, with specific applications to multi-vector district energy systems. The network linkages have been modelled through a multi-vector efficiency matrix specifically developed to map the transformation of final demands into network energy flows while taking into account the inter-network locations of the individual supply technologies. The relevant coupled electrical, heat and gas flow equations have been solved simultaneously using a Newton-Raphson approach. A real case study of a district multi-energy system in the Campus of the University of Manchester illustrates the quantitative use of the model in different scenarios for technical, economic and environmental studies. Sankey diagrams of the energy flows across the networks are also presented to give a visual picture of the multi-energy interactions and losses in the district in different scenarios. The model can be flexibly adapted to generic network topologies and multi-energy supply technologies, and can thus be used for practical operational implementations as well as to inform planning of low carbon multi-vector energy systems.