Estimating Values of Integrated PV-Battery Systems for Single-Detached Residences in Japan

Abstract

Climate change is now widely acknowledged as a threat facing the current generation. To combat this, photovoltaic (PV) power generation, one of the renewable energy sources, has been regarded as a preferable solution to meet the growing energy demands by producing electricity cleanly and sustainably. The utilization of PV has developed at a significant speed at a global scale. Amongst the different types of PV power generation, utilizing it with a combination of battery storage systems, integrated PV-battery systems, at the residential level, are attracting increased attention today worldwide, including Japan. It is believed that the systems will contribute to changing how electricity is produced and consumed, which is a fundamental change to mitigate climate change. However, while the cost of PV systems has decreased over the years, the high cost of batteries causes consumers to hesitate to install PV-battery systems at their homes. This thesis explores the economic return on residential integrated PV- plus lithium ion battery systems in Japan. Using twelve and twenty-four month actual electricity consumption data (12 and 24 month duration to cover all seasons) from single detached houses in Kyoto, Japan, along with data from Japanese government sources and past literature, this study evaluates the expected financial returns of integrated PV-battery systems under 36 scenarios. The primary financial indicators used in this study are Net Present Value (NPV) and Internal Rate of Return (IRR). The results indicated that most of the scenarios did not create positive economic returns. For scenarios which showed negative results, sensitivity analysis was conducted to estimate a break-even cost of battery, as the high cost associated with the installation of the integrated PV-battery systems is one of the main obstacles for wide use of this technology. The results indicated that for the systems to show NPV=0, the cost of batteries needs to decrease substantially. This study provides new knowledge on residential integrated PV-lithium-ion battery systems in the context of the Japanese residential sector, which has not been explored in past literature. This research also holds valuable information for policy makers and associated businesses to enhance the development and use of the systems in the Japanese residential sector.