Teams from all over the world are revving up to compete in a contest to see who has the most energy efficient car.

The 46 teams from 25 countries will drive almost 1,900 miles across Australia’s Outback in solar powered cars as part of their participation in the World Solar Challenge.

The biannual competition requires participants to travel from Darwin, which is in North Australia, to Adelaide, in the southern part of the continent. To make the trek through the torrid desert, teams must design their vehicles to use advanced technologies like solar power conversion and energy storage devices.

There are three classes of vehicles participating in the race: the Challenger Class, the Cruiser Class, and the Adventure Class. But most teams are participating in the first two categories.

The Challenger Class consists of smaller vehicles that carry only the driver and are timed in a single stage between the two destinations. They must travel the full length of the race with just one charge of their battery. Solar power provides the rest of the energy needed to power the vehicle's trip.

The Cruiser Class is for vehicles carrying a driver and passenger. However, the contestants in this class are timed in two stages, from start line in Darwin to Alice Springs (the half-way point) and then again from Alice Springs to Adelaide. Once contestants in this class reach the midway point they can recharge their batteries from the grid. But all extra energy need to power the second half of their 932 mile journey must come from the sun.

While the competition has been going on since 1987, there are key changes in design requirements and charging rules every year forcing the teams to rethink their previous models.

Here’s a look at some of the most impressive vehicles competing this year that have a record of placing in the competition.