Business Insider says Tesla Motors founder Elon Musk, a staunch supporter of alternative energy, is pushing for greater use of solar power, citing a study that shows just how much of the Earth's surface would have to be covered in solar panels to generate enough electricity for the entire planet's needs.

It says you would need about as much land area as Spain.

And that space would obviously be distributed across many different areas.

A map shows that it would be very feasible in terms of the amount of land used.

In many cases, they could be put on rooftops, out of the way.