By Phil Mercer
BBC News, Sydney
Innovations developed for the race are adopted by large car makers
One of the world's toughest endurance races for solar and hybrid cars is underway in Australia.
The Global Green Challenge takes competitors over 3,000km (1,864 miles) of the country's harshest terrain from tropical Darwin to southern Adelaide.
The early front-runner after the first day is a team from Japan.
The race aims to highlight advances in hybrid, electric and low emission vehicles as well as those propelled by the sun.
Japan's Tokai University car is powered by some of the world's most innovative solar cells and leads other entrants from the United States, the Netherlands and Britain.
The sort of aerodynamic design and tyres that improve fuel efficiency, which the competition has showcased over the years, have increasingly been adopted by large car makers.
With the United Nations Climate Change Conference in Denmark just a few weeks away, Professor John Storey, an astrophysicist from the University of New South Wales, says the race shows that the motoring industry can adapt to environmental challenges.
"Going into Copenhagen I would see this event as being, if you like, the ray of sunshine on the horizon in the future to say that look if we have to cut our CO2 by 20%, 30%, 50% or more, it's not the end of the world."
This iconic and gruelling transcontinental race is celebrating its 10th anniversary.
It has attracted 35 teams from more than a dozen countries. The first cars are expected to cross the finish line in Adelaide, the capital of South Australia, on Wednesday or Thursday.