System wide power flow analysis of the Irish distribution network to assess the impact of projected low carbon technology loads and generation including significant increase of electric vehicles connected to the grid

Abstract

Through the Climate Action and Low Carbon Development Act 2021 the Irish Government have set out a commitment to reach net-zero emissions by 2050 and cut emissions by 51 % by 2030 compared to 2018 levels [1]. Reaching these targets will, in no small part, be attributed to the electrification of heat and transport powered by renewable generation. Today Ireland is a country of 5 million people, and there is installed capacity of about 4.5 GW of renewable generation connected to the grid. By 2030, it is projected that one million electric vehicles (EVs) will be charging on a regular basis, 600,000 homes will be heated via heat pump (HP) technology, roof top photovoltaic (PV) will be installed on hundreds of thousands of homes and there will be 5 GW of additional commercial renewable generation connected at distribution level. It is forecasted that by 2030, if unmanaged, EV load will make up approximately 28 % of the total peak demand in Ireland. ESB Networks, Irelands Distribution System Operator has established the ‘National Network, Local Connections” programme which is tasked with introducing and embedding the new systems and processes in order to facilitate the connection and operation of the new Low Carbon Technologies (LCTs), which are comprised of the EVs, HPs and PVs, and the commercial generation, while maintaining a safe, secure and reliable network. The network levels assessed under this programme include the 10 kV, 20 kV and 38 kV systems for the whole country and the 110 kV network in the Dublin area. The Network System Services (NSS) group within ESB have been tasked with analysing the Irish distribution system to identify network constraints relating to the increase in LCT usage, with the view to establish both traditional and non-traditional network solutions, such as utilising flexibility services, to maintain the integrity of the grid. ESB Networks have defined a number of LCT uptake scenarios, generation scenarios and underlying winter peak and summer night valley demand scenarios. The ESB MV distribution system model is comprised of 20 different network areas, and each of these network areas are assessed from a load flow perspective for an 11 year period from 2020 to 2030. Having carried out analysis to determine the worst-case scenario for each network area, NSS have developed network models using Siemens PSS Sincal software. NSS group are using the models to investigate the system load flows and voltage profiles, for normal and standby feeding operation of the entire distribution network for the period from 2020 to 2030. The development and utilisation of Python and VBA scripting tools to analyse and process large data sets of input data and results aids the efficiency of the large task at hand. This paper will discuss scenario modelling techniques, load flow analysis and constraint identification brought on by the changing energy landscape of the Irish distribution system.