Electricity self-sufficiency of off-grid mobile homes as temporary housing: A feasibility study in Japan

• Evaluates off-grid mobile homes’ energy self-sufficiency in Japan's climate zones. • Combines actual measurements with numerical analysis of PV and storage batteries. • Challenges arise during heating periods due to high demand and low solar generation. • Enhances sustainable post-disaster housing with energy-efficient off-grid solutions. The increasing frequency of natural disasters caused by climate change, such as typhoons, torrential rain, and earthquakes, highlights the urgent need for effective and sustainable temporary housing. This study explores the potential for off-grid power independence in mobile homes for disaster recovery in Japan, a region vulnerable to seismic and climatic events. Through measurements and numerical analyses, we assessed the electricity self-sufficiency of mobile homes with photovoltaic (PV) panels and storage batteries across various regions, including Hokkaido and the Nansei Islands. Results indicate significant electricity self-sufficiency during cooling periods, especially in areas with lower cooling loads. Mobile homes equipped with eight PV panels (2400 Wp) can produce over 3000 kWh of electricity annually, surpassing heating and cooling energy needs in all studied areas. However, achieving self-sufficiency during heating periods remains difficult due to higher energy demand during non-generating hours. Expanding PV panels and battery capacity can raise the electricity self-sufficiency rate to over 80 % in non-cold regions but offers limited improvements in colder areas. This study highlights the potential of off-grid mobile homes as resilient, energy-efficient post-disaster solutions and points to the need for further optimization of insulation and design guidelines for diverse climates.