Thermodynamic and preliminary techno-economic analysis of NH3 utilization in combined cycle power plant: Comparison of direct liquid, vaporized, and cracked NH3-Based combustion methods

Ammonia (NH 3 ) is gaining attention as a promising carbon-free fuel for gas turbine combined cycle (GTCC) power generation. However, its effective utilization requires a thorough understanding of combustion characteristics, emissions, and economic feasibility. This study develops a novel process simulation framework for modeling liquid NH 3 (LNH 3 ) combustion, enabling performance, emission, and preliminary techno-economic assessments. Additionally, multiple NH 3 utilization pathways were explored, including direct LNH 3 combustion, gas-phase/vapor NH 3 (VNH 3 ) combustion, and NH 3 cracking-based methods, to identify the most efficient and cost-effective approach. The findings indicate that LNH 3 combustion generates lower NO x emissions than VNH 3 but at the cost of reduced efficiency. NH 3 cracking enhances power output and thermal efficiency with an optimal cracking reactor temperature of 500 °C. Higher cracking ratios improve efficiency and reduce the levelized cost of electricity (LCOE) in both LNH 3 and VNH 3 systems. Efficiency increases from 47.7 % (LNH 3 ) and 49.1 % (VNH 3 ) to 54 % in H 2 –N 2 combustion (complete NH 3 cracking). However, LCOE is highly sensitive to cracking reactor costs and NH 3 prices. At low NH 3 prices (320 USD/t), direct VNH 3 combustion (0.217 USD/kWh) is more economical than VNH 3 cracking (0.22 USD/kWh), whereas in LNH 3 systems, cracking is always favorable. Furthermore, a higher pressure ratio for GTCC with a lower pressure in the NH 3 cracking reactor is preferred. This research provides new insights into NH 3 combustion strategies, offering a comprehensive techno-economic evaluation to guide optimized power generation with minimal environmental impact. Future work should refine NH 3 cracking models and establish emission-compliant operational limits for commercial deployment. • LNH 3 combustion was modeled, validated, and compared to VNH 3 . • LNH 3 combustion yields lower NO x but also lower efficiency than VNH 3 . • NH 3 cracking improves power output and lowers LCOE, especially in LNH 3 . • Cracking economics depend heavily on NH 3 price and reactor cost. • High pressure ratio of the gas turbine with a low pressure of cracking reactor is preferred.