Comparative Evaluation of Solar Radiation, Photovoltaic Potential, and Renewable Energy Policy Frameworks in the United Kingdom and Nigeria Using Liu and Jordan Model and PVsyst Simulation

Abstract: This study presents a comparative evaluation of photovoltaic (PV) system performance and renewable energy policy frameworks in the United Kingdom and Nigeria using London and Abuja as representative case studies. The research integrates solar radiation estimation using the Liu and Jordan model with PVsyst simulation to assess photovoltaic energy generation under different climatic conditions. Monthly solar radiation values were calculated and compared for London and Abuja using both the Liu and Jordan method and PVsyst simulation software. Three comparative analyses were performed: comparison of Liu and Jordan and PVsyst results for London, comparison of Liu and Jordan and PVsyst results for Abuja, and comparison of calculated Liu and Jordan monthly radiation values between London and Abuja. Results indicate that Abuja possesses significantly higher solar radiation and photovoltaic energy yield potential than London. PVsyst simulation values were consistently higher than Liu and Jordan calculated values due to the incorporation of advanced meteorological parameters and environmental losses in the simulation software. The study further reveals that despite Nigeria’s superior solar resource availability, the United Kingdom has achieved greater photovoltaic deployment because of stable policies, financing accessibility, strong institutional frameworks, and advanced grid infrastructure. Major barriers affecting photovoltaic implementation in Nigeria include inadequate financing mechanisms, weak policy implementation, poor grid infrastructure, and shortage of skilled technical personnel. Recommendations including feed-in tariff mechanisms, concessional financing, grid modernization, local manufacturing, and technical workforce development are proposed to accelerate photovoltaic deployment in Nigeria.