Utilization of Rooftop Solar Units to Generate Electricity and Hydrogen: A Technoeconomic Analysis

Abstract

This study is aimed at scrutinizing the domestic solar energy potential for electricity and hydrogen production. Under the first scenario, it is sought to evaluate electricity generation for household purposes using RSUs (rooftop solar units). Then, under the second scenario, solar hydrogen production is analyzed for the purpose of meeting a hydrogen vehicle demand. For this, one of the aptest cities, Yazd, located in the center of Iran is investigated. Furthermore, a real-world electric load needed by an usual household in Yazd is deemed as the demand for electricity. To analyze the two scenarios, a system consisting of an 8.2 kW RSU for power generation, a battery for electricity storage, and a 1 kW electrolyzer for hydrogen yield is proposed. Also, to acquire a broader vision, predictions are made for the next 10, 20, 30, and 40 years. The results regarding the first scenario implied that COE (Cost of Electricity) would be, respectively, 0.067, 0.145, 0.136, and 0.127 $/kWh. In addition to supplying the electricity required by the house, 2,687 $/yr could be earned by selling the excess electricity generated, and 5,759 kg of CO2 would be avoided a year. The findings as to the second scenario showed that LCOH (levelized cost of hydrogen) would equate to 3.62, 6.53, 6.34, and 5.93 $/kg, respectively, for the aforementioned project lifetimes. Furthermore, 2,464 $/yr would be the revenue after selling the surplus electricity, and 7,820 kg of CO2 would be saved, annually.