Performance Analysis of Grid-Tied Solar Photovoltaic Systems Installed at Government Institutions in Ogun State

Background: Grid-tied solar PV installations at Nigerian government institutions represent significant public investments whose performance requires systematic evaluation to ensure returns and inform future procurement. Aim: This study analysed the performance of grid-tied solar PV systems at government institutions in Ogun State, South West Nigeria. Methods: Energy yield, performance ratio, and capacity utilisation factor were evaluated at 10 grid-tied PV installations using data from inverter monitoring platforms and utility export meters. System ratings ranged from 10 to 100 kWp. Data covered a 24-month monitoring period. Results: Mean performance ratio across all installations was 74.2%, below the industry benchmark of 80%. Capacity utilisation factor ranged from 14.1% to 18.7%. Common performance losses were attributed to inverter faults (32%), grid outages forcing islanding shutdown (28%), and module soiling (18%). Energy yield averaged 1,380 kWh/kWp/year. Conclusion: Grid-tied PV performance is significantly below potential due to grid reliability issues and inadequate maintenance. Recommendations include preventive maintenance schedules, battery backup integration for critical institutions, and performance-based maintenance contracts. Keywords: grid-tied solar PV, performance ratio, government institutions, Ogun State, energy yield.