Probabilistic modeling and assessment of the impact of electric heat pumps on low voltage distribution networks

Electrification of heating by making use of the Electric Heat Pump (EHP) technology powered by increasing shares of electricity renewable sources is seen as a potential key approach to decarbonise the energy sector in many countries, and especially in the UK. However, the widespread use of EHPs in substitution of fuel boilers might cause significant issues in terms of electrical distribution network impact, particularly at the low voltage (LV) level. This has not been addressed properly in the studies carried out so far also due to lack of available data and suitable models. In this light, this paper introduces a novel and comprehensive probabilistic methodology based on Monte Carlo simulations and a relevant tool to assess the impact of EHPs on LV distribution networks. Real electricity and heat profiles are taken as a starting point of the studies. Both Air Source Heat Pump (ASHP) and Ground Source Heat Pump (GSHP) types are modeled as black boxes with performance and heat capacity characteristics changing with operating conditions according to manufacturers’ curves, addressing in particular the need for and impact of different types of Auxiliary Heating (AH) systems. A specific LV network analysis tool has been built that integrates the three-phase unbalanced power flow solution engine OpenDSS with the developed EHP models and is capable of properly addressing single-phase connections, adequately modeling the unbalanced nature of LV networks. Different metrics are used to quantify the impact of the considered technologies, with emphasis on thermal and voltage limits, according to current engineering standards. To cope with the many relevant uncertainties (EHP size, location in the network, operation pattern, reactive power consumption, network headroom, etc.), various case studies and sensitivity analyses have been carried out for representative suburban areas in the UK and for different scenarios in order to exemplify the developed methodology and illustrate the main drivers for impact and trends in the different cases. The tool can be adapted to perform studies for different situations and scenarios and can be used as decision making support by network operators, energy planners, policy makers, and so on, to better quantify the potential implications of large scale electrification of heating.