Next environment-friendly cars: Application of solar power as automobile energy source

We investigate the benefits of utilizing solar power as an energy source for future automobiles. Since there are strict emission standards developed by governments, we must find an alternative energy source for the future automobiles. We show that replacing all passenger cars with hybrid vehicles equipped with a 800 W rated-power solar module would reduce greenhouse gas (GHG) emission by 63% in Japan. We obtained an average power generation of 2.1 kWh/day over 100 days by solar modules installed on a Prius under the real environment, which was larger than the required power to achieve the GHG emission reduction. We also investigate an innovative statistic low-concentrator with III-V cells in order to reduce installation area for the automobiles. We show that our proposed design (asymmetric-aspheric design) can expand the acceptance incident angle and increase the annual energy yield, while keeping thin structure, which is essential to automobile application.