Economic Feasibility Assessment of Solar Photovoltaic Rooftop Installation for Buildings in Northern Thailand

Abstract

Thailand's commitment to renewable energy and reducing carbon emissions has made solar photovoltaic (PV) technology increasingly important, given the country's high solar irradiance and favorable climate. This study examines the economic viability of a 120-kW rooftop PV system for the Uttaradit Teacher Savings and Credit Cooperative building in Northern Thailand. The objectives are to lower energy costs and support Thailand's renewable energy goals. This research assesses the feasibility of the proposed system using financial indicators such as Net Present Value (NPV) and Payback Period, along with an analysis of CO2 emissions reduction across three scenarios: (1) direct calculations using local solar irradiance, (2) energy production simulation with PVsyst software, and (3) comparison with existing PV installations in Uttaradit Province. The findings indicate that the system can generate between 133,793.2 and 190,800 kWh per year, with a payback period of 4.92 to 7.64 years and a positive NPV in all scenarios. The system also has the potential to reduce CO2 emissions by 75.78 to 108.07 tCO2eq/year annually. Sensitivity analysis shows the system’s resilience to changes in equipment costs, electricity prices, and maintenance expenses, confirming its viability as a sustainable investment. This study highlights the economic and environmental benefits of rooftop PV systems in Thailand’s cooperative sector and emphasizes their role in supporting the country’s renewable energy transition.