As Iran is rich in oil and gas resources, renewable energy was known as a luxurious source of electric power generation for a long time. New policies and targeted subsidy reform plan for fossil fuel products have changed the view of decision-makers and energy sector investors toward renewable energy resources. According to the climatological studies, two-thirds of Iran's land has three hundred sunny days which indicates great potentials for providing solar energy. This paper deals with small-scale solar energy potentials in different cities of Iran. The considered solar systems are based on the combination of photovoltaic panels in order to obtain the nominal values of 1, 5 and 10 kW for 15 selected cities of Iran. Design of the photovoltaic (PV) systems is carried out based on optimum fixed tilt angles of the panels and efficiency variation due to the temperature changes of different locations. The final decision on financial assessment of the mentioned solar PV projects is based on different concepts of engineering economy such as rate of return (ROR), present worth of benefit and cost (PWB, PWC), extra investment analysis, levelized cost of energy (LCOE). The amount of calculated income and the expected benefit are also investigated under certainty and uncertainty of guaranteed solar electricity purchase tariff in a 30-year project lifetime.
