Solar energy represents the main renewable source development trend in the world to address the problems of energy shortage and environmental pollution. The development of power electronics and semiconductor technology helps to lower the cost of installing solar projects, speeding up building many solar power plants around the world, especially in China and America. In parallel, with the large capacity solar power plant, small solar systems are also receiving much attention from small capacity consumers. Rooftop systems are seen as a cost-saving solution for loads in the need to use the grid and to increase the proactive power supply for consumption loads. Installing a rooftop system must always be considered in terms of design capacity, cost, efficiency and capital recovery. This study builds a rooftop system with the capacity of 2 kW for a household load in Vietnam, which has a high potential for solar power development. Assessing the amount of capacity obtained by simulation and experimental methods, and economic factors are also presented. The results reflect the operability of the installation system, the errors between simulation and reality and are evaluated the indicators of economic efficiency of the photovoltaic rooftop system, which are not mentioned in previous studies. The economic values show the benefits of the system when the cost of paying to the power company is low but the ability to recover the project’s capital is quite long.

Keywords: Economic indicators, Electricity saving, Power grid, Rooftop, Solar energy