The aim of this study is to perform an economic and environmental feasibility study of switching the electrical power supply of a small building located in Dhahran, Saudi Arabia, from the electrical grid into renewable energy provided by solar photovoltaic (PV) modules. The PV power plant is evaluated based on the international Photovoltaic Project Model with the same power capability of 12kW. The feasibility study was based on the new electricity tariffs for the governmental and commercial sectors of 4.0 and 8.0cents/kWh, respectively. Three scenarios were considered for several cities of Saudi Arabia, taking into account the most recent prices for a PV system. The first two scenarios were evaluated with the same input parameters except for the electricity tariff (USD/kWh) for a complete switching from grid electricity to a solar PV system. The equity payback periods were found to be 14.1 and 8.2 years, respectively. The reduction in the equity payback period by doubling the electricity tariff is about 41%. Significant differences were not observed when the techno-economic data for the different cities were compared, most likely due to the similar climate of the cities. The resulting reduction in GHG emissions is about 70 tCO2. A third scenario with partial power switching was evaluated for Dhahran for comparison purposes. In this scenario, the power demand is met by both solar PV (27%) and grid electricity (73%). The equity payback period is significantly increased to 21.7, while the reduction in GHG emissions is a minimum at 23 tCO2.