Choices of Solar Energy Storage for a Sustainable Urban Society: Economic Assessment for a Small Household

Solar energy is a renewable energy source and is clean, pollution-free, and cost-free. The use of solar energy as an energy resource can bring positive changes in human life. It also helps to slow down the global warming. Thailand is located near the equator resulting in high solar irradiation. The average solar radiation intensity across the country is 17.49 MJ/m²-day. However, there are significant limitations in the utilization of solar energy, such as it can be available only during the daytime. Therefore, this research aims to study alternative ways to use and store the solar energy by collecting related data for nighttime use in small households. Both in the forms of electrical energy using solar cells (Photovoltaic Cell: PV) and heat energy by using the solar collector. It also includes solar drying using parabolic rails in conjunction with a phase change material (paraffin) energy storage system. The results show that battery-based solar energy storage has the highest initial cost and slowest return on investment, with a cost of 1,459.20 USD and a payback period of 26.61 years. On the other hand, the solar energy storage system in the form of heat energy using paraffin and water mediums has a lower initial cost and a faster payback period, especially for the dryer with paraffin, which has a cost of 227.26 USD and a payback period of 0.76 years. The other cost-effective option is the hot water system, which has a cost of 302.06 USD and a payback period of 1.71 years. However, each energy storage system has its own characteristics. Interestingly, the battery energy storage has a significant advantage over other systems which can be used as a power source for variety of electrical appliances. This causes more convenient for daily life style. Although the cost of the system is relatively high, it is an interesting approach if applied in some areas where the public power transmission system cannot be reached.