Net Plant Heat Rate (NPHR), Specific Fuel Consumption (SFC) and Fuel Cost is one of the key parameters in evaluating the thermal efficiency of a Steam Power Plant (PLTU). NPHR represents the amount of heat energy required to generate one unit of net electrical energy, SFC represents the amount fuel quantity required to generate one unit of net electrical energy while Fuel Cost represents the fuel cost required to generate one unit of net electrical energy. This study aims to analyze the effect of generator loading on the values of NPHR, SFC, and Fuel Cost at PLTU Labuhan Angin Unit 1. Operational data from the power plant were collected over a specific period under varying load conditions. The analysis results show that increased power plant loading is inversely proportional to the values of NPHR, SFC, and Fuel Cost, indicating that thermal efficiency improves as the load increases up to a certain optimal point. This study highlights the importance of operating power plants within an optimal load range to maximize efficiency and minimize fuel consumption and cost.