Decarbonisation of district heating network and its interaction with electricity distribution network, a case study in South-Holland

Abstract

The decarbonisation of district heating networks (DHNs) is one of key ways in achieving the net-zero climate targets, especially in densely populated and energy consumption intensive regions like South-Holland in the Netherlands. As DHNs transition from fossil-based to renewable and electrified heat sources, the interactions with the electricity distribution network (EDN) becomes increasingly more critical. Nevertheless, current operational models and planning approaches often treat the development of heat and electricity networks separately, not considering their interactions and overlooking the operational and infrastructural challenges that arise from their growing interdependence.

This thesis addresses this gap by presenting an integrated modelling framework that combines an operational optimisation model of the South-Holland DHN, developed using PyPSA, with a time-series power flow analysis of the South-Holland EDN using pandapower. The South-Holland case study is carried out in which the implemented framework simulates hourly network operations across the future energy scenarios for the years 2030, 2040 and 2050. These scenarios are driven by real-world market data of electricity, natural gas and CO2 prices, weather patterns, as well as future heat and electricity demand profiles. This master thesis is part of the TU Delft research project "DEMOSES" and is done in collaboration with Eneco and Stedin.

The results highlight that the large-scale introduction of electrified heat sources in the South-Holland DHN, such as heat pumps, electric boilers and geothermal energy plants, substantially reshapes the operation of the DHN and the loading patterns of the EDN. The operation of the DHN shifts from a more demand-responsive to a market-driven network, with a large reliance on the electricity market signals. This flexibility and responsiveness is largely driven by strategically placed thermal energy storage, especially near electrified production units. Moreover, the electrification of heat supply vastly reduces the reliance on gas and CHP units, resulting in geothermal energy, industrial waste heat and waste incineration becoming the key heat supply technologies. However, it also significantly increases the loading levels of key distribution network components, particularly on medium voltage transformers and lines, leading to critical network stress under future demand scenarios. Conversely, in future scenarios in times of high distributed energy generation, the addition of power-to-heat sources reduce the loading levels of the critical EDN components. It was identified that in times of high distributed energy generation, which results in net negative demand, the power-to-heat sources can consume power locally, lowering the amount of electrical power that needs to be transferred to the HV network, consequently reducing line and transformer loading. The reinforcement of physical assets and coordinated planning efforts between DHN and EDN operators are identified as key factors in mitigating these risks effectively.

Overall, this study provides a detailed description and analysis of the development of the integrated South-Holland heat and electricity model. In addition, the models are applied to perform multiple experiments in the case study, which allows to gain practical insights regarding the effect of large-scale electrification of the South-Holland DHN on the heat network itself and the EDN. The need for spatial-temporal coordination between heat
and electricity network operators in the operational and network planning of integrated energy systems is highlighted. The proposed methodology serves as a practical tool for decision makers and policymakers seeking to balance the decarbonisation goals of the DHN with the EDN reliability.