Electricity consumption contribution to power system inertia — Case electric vehicles and thermostatically controlled loads in Finland

Abstract

Generation of inverter-connected solar and wind power displaces kinetic energy in power systems, decreasing frequency quality and threatening the system security. As a solution, this paper investigates the potential of electricity consumption to increase the inertial response of the system so that the frequency quality is maintained. The study focuses on three types of consumption: Electric vehicle (EV) charging, direct electric space heating (DESH), and the consumption of refrigerators, which all have different characteristics in terms of their response to the power system frequency. We aim to assess their potential inertia contribution in a Finnish case study. Therefore, the study firstly introduces the consumption models with required load control strategies, after which the performance of the loads as a part of the Nordic power system frequency dynamics is simulated. The results indicate that the loads are able to contribute to the system inertia but their consumption may not coincide with the moments of low system kinetic energy.