Transient Analysis of Hydrogen Co-Fired Gas Turbines During Load-Following Operation

Abstract Efforts are being made to use hydrogen as a fuel in gas turbines to reduce CO2 emissions. Predicting operating point shifts accurately is crucial for applying hydrogen co-firing. In recent studies, the shift in operating points under full-load conditions was investigated based on hydrogen co-firing ratios and steady -state analyses. It was confirmed that the extent and direction of the operating point shift vary depending on the applied scenario. Building on the results of those studies, this research aims to analyze part-load operations, especially using a transient analysis. Gas turbine part-load operation is controlled to follow a predefined control curve. However, hydrogen co-firing induces operating point shifts, requiring new control curves. In this study, part-load control curves for various co-firing ratios and scenarios were derived, and their transient effects during load-following operation were analyzed using a PID control system. When hydrogen co-firing is applied, dividing the PID gain value by the ratio of the heating value of the mixed fuel to that of natural gas allows for transient effects similar to those observed when using only natural gas. This approach can be generally applied regardless of the co-firing ratio or scenario and provides a guideline for adjusting PID gain values in systems utilizing hydrogen co-firing.