| Title |
Economic Analysis by ESS Capacity and Assessment of an Applicable Capacity Range for a Self-Consumption PV-ESS System Considering the Load Characteristics of a Vocational Training Institution |
| DOI |
https://doi.org/10.5207/JIEIE.2026.40.4.301 |
| Keywords |
Economic feasibility; Energy storage system; Industrial electricity tariff; Photovoltaic system; Self-consumption; Vocational training institution |
| Abstract |
This study evaluates the economic feasibility of integrating an energy storage system (ESS) with a self-consumption photovoltaic (PV) system for a vocational training institution operating under an industrial electricity tariff. A 39.6 kWp PV system was modeled using PVsyst, yielding an annual electricity generation of 51,288 kWh, a specific yield of 1,295 kWh/kWp·yr, and a performance ratio (PR) of 88.32%. Based on the results of a previous PV study and the facility’s daytime load characteristics, the baseline self-consumption ratio was set to 80%. Four ESS capacity scenarios (20, 40, 60, and 80 kWh) were analyzed using an incremental cash-flow approach. The annual net benefits of the ESS scenarios were estimated at KRW 338,524, KRW 523,184, KRW 553,980, and KRW 430,912, respectively. The corresponding payback periods were 29.5, 38.2, 54.2, and 92.8 years, while all net present values (NPVs) were negative at a 6% discount rate, indicating that none of the scenarios achieved economic feasibility under the assumed conditions. As a case study of a vocational training institution, the results indicate that ESS integration improved the self-consumption ratio but did not provide sufficient economic benefits to justify the investment. If ESS installation is required for policy or operational purposes, the 20?40 kWh range may be considered a preliminary capacity range for further evaluation. However, this should not be interpreted as an economically optimal or generally applicable ESS capacity. |