Operational Viability of the Afam Combined-Cycle Station

Abstract

This study evaluates the operational viability of the 650 MW Afam VI combined-cycle station in Nigeria (three 150 MW gas-turbine units and one 200 MW steam-turbine unit) over the period 2010 to 2020. First-law performance equations were applied to the gas-turbine, heat-recovery steam generator and steam-turbine segments to obtain net power, combined-cycle efficiency, heat rate and steam-cycle heat supply. Capacity factor and availability were computed from generation and running-hour records, and the levelized cost of electricity (LCOE) was used for the economic comparison. The calculations were processed in MATLAB. Mean combined-cycle efficiency was 53.13%, mean availability 92.16%, mean capacity factor 79.49% and mean LCOE N36.43/kWh. Combined-cycle efficiency remained in the 49–56% band throughout the review period. The results give plant managers and energy planners an evidence-based account of station performance under Nigerian operating and cost conditions.