Performance Assessment of a Standalone Residential Solar PV System for a 19.8 kWh/day Load: A Comparative Study of Abuja, Beijing, and Washington DC

Abstract

This study presents a comparative techno-economic assessment of a standalone residential solar photovoltaic (PV) system with LiFePO₄ lithium-ion battery storage designed to meet a relatively high household electricity demand of 19.8 kWh/day across Abuja (Nigeria), Beijing (China), and Washington DC (USA). PV system simulations were performed using PVsyst, while economic analysis was conducted over a 25-year project lifetime. Independent validation was additionally carried out using HOMER Pro. The results show significant variation in solar resource availability, with Abuja recording the highest global horizontal irradiation (2,042 kWh/m²/year), followed by Beijing (1,564 kWh/m²/year) and Washington DC (1,503 kWh/m²/year). The standalone PV systems demonstrated strong technical performance in all locations, achieving solar fraction values above 0.93, indicating reliable operation for high-demand residential applications. Beijing achieved the lowest levelized cost of electricity (LCOE) of 0.176 USD/kWh and the lowest net present cost (NPC), while Washington DC exhibited the weakest overall techno-economic performance. Despite the favorable technical performance, all locations produced negative net present value (NPV) results, indicating that the standalone PV systems were not economically competitive with prevailing grid electricity tariffs under the adopted assumptions. Sensitivity analysis identified discount rate and battery storage cost as the most influential economic parameters. The HOMER Pro validation showed good agreement with the PVsyst results for annual energy production, LCOE, and NPC, confirming the robustness of the adopted simulation methodology. The findings demonstrate that both solar resource availability and local economic conditions strongly influence the feasibility of standalone PV systems for high-demand residential applications.