Estimation of the optimal government rebate for promoting the photovoltaic system in multi-family housing complexes

The government rebate has become one of the important drivers for implementing the photovoltaic (PV) system. However, it is not as effective for the multi-family housing complexes (MFHCs) in South Korea due to the constant government rebate without considering the electricity generation of the PV system by region and the electricity consumption by MFHC. Thus, this study aimed to estimate the optimal government rebate that guarantees the economic profitability of the PV system within the 4-year target payback period set by the South Korean government to encourage the installation of the PV system in MFHCs. Towards this end, based on the 16 administrative divisions in South Korea and the three types of electricity consumption, this study established 48 scenarios for analyzing the life cycle cost and life cycle CO2. When the annual electricity generation of the PV system decreased from 357,300 to 302,090 kWh, and when the monthly average electricity consumption per household by MFHC increased from 200 to 600 kWh, the ranges of the optimal government rebate decreased from US$1,406-1479/kW to US$649-838/kW. When the target payback period increased, the optimal government rebate, which guarantees the economic profitability of the PV system within the 4-year target payback period, decreased. This study may be useful for decision-makers (i.e., residents, construction managers, etc.), or policymakers to determine the optimal government rebate that meets the economic profitability of the PV system in terms of the life cycle cost and life cycle CO2.