Thermodynamic Performance Enhancement of Gas Turbine Power Plants through Steam Injection: Energy Analysis of Ihovbor Power Plant

Abstract

This study presents a comprehensive energy analysis of the Ihovbor Gas Power Plant in Nigeria, evaluating its performance in both simple cycle and steam-injected gas turbine (STIG) configurations. The research focuses on quantifying improvements in power output and thermal efficiency. Results indicate that retrofitting with steam injection significantly enhances plant performance, increasing net power output by 37.495 MW, cycle efficiency from 33.92% to 36.79%, and thermal efficiency from 34.44% to 37.35%. A critical finding is the near halving of heat lost to flue gas, from 236.486 MW to 124.288 MW, demonstrating effective waste heat utilization via a Once Through Steam Generator (OTSG). Parametric analyses reveal that while performance generally improves with increased pressure ratio and turbine inlet temperature, and decreases with rising ambient temperature, the STIG system exhibits greater resilience to ambient temperature fluctuations. The study identifies an optimal steam fraction for maximum efficiency and underscores the STIG cycle as a viable, cost-effective solution for power augmentation in the Nigerian power sector.