One of the problems with electric cars is that while they are cheap to run and emissions-free, the electricity to fuel them still has to come from traditional energy sources.

But by using solar photovoltaic cells you can convert energy from the sun — which is both free and sustainable.

It’s not a flawless plan as production of the cells and batteries uses energy and right now the solar set up is expensive. But could solar energy be the way forward for cars?

We’re a long way off fully solar-powered cars going into production — you can’t get enough charge from panels that fit a regular car’s roof to run a car. But the use of solar power is starting to creep into the mainstream.

Buy an Audi A8 and you’ll have the option to add a solar panel sunroof that can enhance the air-conditioning.

On the 2010 Toyota Prius, you’ll be able to include a solar panel that powers an electric fan to cool the interior.

Other solar-boosted cars come from Koenigsgegg, Pininfarina-Bollore and Fisker. Cars might lack space for solar cells, but panels on garage roofs could boost solar power potential.

Right now the only completely solar power-driven cars out there are prototypes designed to showcase the potential of photovoltaic cells.

Most look like flying saucers — ultra-lightweight, with minimum passenger space and plenty of surface area for panels.

Solar power pioneers set annual challenges to showcase development in batteries and the technologies.

Teams of students race cars that use as much power as a hairdryer does from Texas to Alberta, Canada in the North American Solar Challenge. This October sees the 10th edition of the World Solar Challenge, with solar-powered corporate and academic boffins driving solar-powered vehicles 3000km from north to south Australia.

And there’s the rub: you can travel for days on sun-power if you live in climate-change-ravaged Australia, but how far can you go if you live somewhere where it rains all year?

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