38 Solar powered cars departed Darwin yesterday, bound for Adelaide, 3000kms away. This year, the solar cars are accompanied on their journey across Australia by 19 energy-efficient vehicles showcasing technology inspired by the Solar World Challenge. The event, which takes place every two years, helps push forward research into vehicle efficiency. We'll probably never see a mainstream solar car, but the technology developed here to store and release electric power in an efficient manner has wide-ranging applications in future green vehicles. [World Solar Challenge]