Aside from impractical science experiments, we haven't been able to tap into the sun's energy to power our cars. Ford thinks it has a solution, and it involves a plug-in hybrid, a solar panel mounted on the roof, and a canopy that acts like a magnifying glass. Oh, and the car has to be autonomous, too.

At CES, Ford will unveil the C-Max Solar Energi Concept, a lightly modified version of its compact plug-in hybrid crossover, with 1.5 square meters of flexible solar panels glued to the roof.

The standard C-Max Energi gets around 20 miles of all-electric power after charging the on-board battery. With the Solar concept, Ford has nixed the need to plug in the C-Max by harnessing the sun's rays to top up the lithium-ion packs. But the solar panels are only good for around 300 watts of juice – which would take days to fill the 8 kWh battery.

So to make it work, Ford envisions a series of freestanding canopies equipped with a solar concentrator. Think of it like a magnifying glass that can condense the sun's energy and point it directly at the C-Max's solar panels. The only problem is the sun – you know – moves.

To keep the C-Max in the optimal position to harness the solar energy, it would have to autonomously move underneath the panel, tracking the sun's arch over the earth.

With all these puzzle pieces in place, Ford says the battery could be charged in about four hours, but we suspect that our friendly star will burn out before this thing ever sees production.

Correction: An earlier version of this article misstated the claims about the sun's "energy".