Extended Thermo-economic Metrics and Sustainability Potential of Small Wind Energy Systems: A Case-Based Analysis
Abstract
This study assesses wind energy potential across six locations in Cross River State, Nigeria, for small-scale Wind Energy Conversion Systems (WECS). Annual mean wind speeds ranged from 3.38 m/s at OGP1 to 5.3 m/s at OBUP5, with no site recording speeds below 3 m/s, indicating suitability for wind applications. Power and energy densities spanned 6.8-102.9 W/m² and 4.49-85.58 kWh/m², respectively, with the highest values at OBUP5 and AKP4. Exergy-based indicators were analysed; Bergey XL.1 showed a 70.37% increase in the Exergetic Sustainability Index (ESI), a 9.09% rise in Waste Exergy Ratio (WER), and a 33% gain in Useful Speed Volume (USV), demonstrating efficient airflow utilization. Proven-2.5 kW and Skystream-3.7 kW exhibited ESI increases of 46% and 52%, respectively. Exergetic equivalents of labour (𝑒𝑒l) ranged from 43.36 MJ (OGP1) to 65.04 MJ (BKP3), while capital equivalents (𝑒𝑒c) varied from 64.88 MJ/$ to 80.11 MJ/$. Cost of energy (COE) values ranged from $0.063/kWh (BKP3, Proven-2.5 kW) to $0.181/kWh (OBRP6, Skystream-3.7 kW), confirming both technical and economic viability.