Comparative Analysis of Thermodynamic Performance and Emissions of Natural Gas and Ammonia as Fuels for an H Class Gas Turbine

Background: Ammonia is a carbon-free fuel candidate, but its performance in utility-scale H-class gas turbines requires assessment under representative plant operating conditions. Objective: To compare the performance of natural gas and ammonia, their respective fuel requirements, and their predicted equilibrium emissions in a GE 9HA.02 gas turbine at PLTGU Cilamaya. Methods: A steady-state model was developed in DWSIM using the Peng–Robinson property package and a Gibbs reactor and was evaluated at five load conditions derived from distributed control system (DCS) data. Simulations at equal fuel mass flow rates were compared, and inverse regression was used to estimate the ammonia mass flow rates required to achieve equivalent net power output. Results: Net power output ranged from 199.227 to 592.771 MW for natural gas, compared with 70.455–228.870 MW for ammonia at equal fuel mass flow rates. Ammonia provided 37.58% of the natural gas heat input and retained 32.28–38.61% of its net power output. Thermal efficiency ranged from 28.85% to 49.96% for natural gas and from 27.15% to 51.33% for ammonia. Inverse regression estimated ammonia mass flow rates of 22.214–47.093 kg/s; these estimates require load-specific verification. The model predicted zero direct CO₂ emissions from pure ammonia and a 94.91–96.36% reduction in equilibrium NO mass flow rate. A weighted performance index favored Load III among the modeled conditions. Conclusion: Ammonia substitution requires higher fuel mass flow rates and further assessment of combustion behavior and equipment constraints. The available calibration evidence does not establish independent model validation. Equilibrium NO predictions and extrapolated estimates of ammonia requirements for equivalent net power output are insufficient to establish full-scale operating feasibility.