Over 90 teams gathered at the Suzuka Circuit in Japan for the 18th Dream Cup, a solar-powered race organised by the Japan Automobile Federation (JAF).

The race, part of the FIA Alternative Energies Cup, features solar cars powered by one or more electric motors. These are fueled by solar panels which change solar energy into electricity preserved in batteries onboard.

Technological development is rampant throughout the competition. Some of the top teams are now using highly efficient solar cells made from gallium arsenide, which has an energy conversion efficiency of around 25 per cent, much higher than that of normal silicon solar cells. Most teams have also adopted kinetic energy recovery systems, which transfer the braking energy into electricity.

During the race, teams monitor the electricity generation from the onboard solar cells, the amount of electricity used every lap and the energy left in batteries, whilst factoring in climatic changes to give their driver the best racing pace to finish the race.

The key to winning the race is energy management, with teams deliberately changing their pace to confuse the strategy of rival teams trying to estimate the amount of electricity left in other vehicles. The common factor between all cars is that they produce no emissions and also pass stringent safety requirements.

This year’s race was won by the Osaka Sangyo University team.