Power system economics is a research field that applies economic principles and methodologies to the analysis, design, operation, and regulation of electrical power systems. It investigates the complex interactions between technical constraints, market forces, and policy objectives, focusing on topics such as electricity market design, investment planning, operational efficiency, pricing mechanisms, and regulatory frameworks. Characterized by its interdisciplinary nature, it is significant for informing decisions aimed at enhancing the economic efficiency, reliability, security, and environmental sustainability of electricity supply.