Techno-economic assessment of the residential photovoltaic systems integrated with electric vehicles: A case study of Japanese households towards 2030

Finding economical and sustainable pathways for the deployment of renewables is critical for the success of decarbonizing energy systems. Because of the variable nature of renewable energy, however, it becomes increasingly costly when the renewable penetration becomes higher. The recent rise of electric vehicles (EVs) provides us with an opportunity to increase self-consumption of solar photovoltaic (PV) at households with substantially less additional costs. In this paper, we conducted an economic assessment of residential PV systems integrated with EVs (V2H: Vehicle to Home) at Japanese households towards 2030, incorporating the cost projections of these technologies in the future. We found that a system that consists of PV and an EV is already cost-competitive with the use of grid electricity and a gasoline vehicle in 2018. By 2030, the combination of PV + EV would substantially improve the energy economics at households in Japan, reducing annual energy costs (electricity and gasoline) by as much as 68 % in 2030 and decarbonizing the household energy system by 92%. We also found that the PV + EV system is much more economical than a PV-only or PV + battery systems, due to the fact that EV's large battery can be utilized with minimum additional costs. To facilitate the deployment of the combination of PV + EV, policy makers should reinforce policies to enhance EV, PV, V2H penetration, which will ultimately allow more renewables to be deployed in a cost-effective way.