Energy system monitoring is the systematic process of collecting, analyzing, and interpreting quantitative and qualitative data pertaining to energy generation, distribution, and consumption within a defined system. As a research concept and methodological approach, it rigorously investigates energy flow dynamics, usage patterns, trends, and inefficiencies. Its key characteristics involve data acquisition, often in real-time, and the application of analytical techniques and computational tools; its significance lies in providing the empirical foundation necessary for understanding, optimizing, and managing energy performance, thereby informing strategies for efficiency improvements, cost reduction, and system reliability.