Journal of the Korean Solar Energy Society ISSN:1598-6411(Print) 2508-3562(Online) 한국태양에너지학회 논문집

Building-integrated photovoltaics (BIPV) serve the dual purpose of acting as a building’s façade while simultaneously generating electricity. Although a BIPV system installed facing south achieves the maximum power generation at noon on clear days, electrical loads in most buildings occur at varying times throughout the day. When power generation from BIPV systems exceeds the electrical load of a building, surplus electricity is transmitted to the grid managed by the Korea Electric Power Corporation (KEPCO). However, if the surplus electricity exceeds the acceptance limit for the grid, power generation from the BIPV system is curtailed. To address this issue, an energy storage system (ESS) must be installed to store surplus electricity and reduce grid load. In this study, we investigated the problem of power curtailment caused by surplus electricity in a library building equipped with a BIPV system. To do so, we used the PVsyst software package to analyze the performance of a BIPV system integrated with an ESS. The results of the analysis indicate that surplus electricity from the BIPV system exceeding the grid acceptance limit necessarily led to power curtailment to maintain a stable grid voltage and frequency. Specifically, we observed that the operation of a simulated BIPV system halted in intervals when surplus power exceeded 7 kWp. To resolve this issue, we integrated an ESS in the simulation that was able to store all the surplus electricity and utilize it within the building instead of feeding the power back into the grid. This approach enabled the building to meet its entire power demand solely from BIPV-generated electricity for up to 7 hours. Consequently, approximately 57% of the library's 13-hour daily operation could be supported by self-generated power. Thus, our results confirm that integrating an ESS with BIPV systems may be expected to enhance the stability of the grid and increase the amount of energy a building can save. Ultimately, the findings underscore the necessity of integrating an ESS with BIPV systems to save electricity and improve energy efficiency. Eventually, the systems could be developed further to realize buildings with zero net energy consumption from the grid.