At just 15mm thin and 1.22 kg, the Yoga Solar PC is the world’s first ultraslim solar-powered computer, packing a hidden superpower: a solar panel with a 24%+ energy conversion rate. The result?

The cells are made of semiconductor materials like those found in computer chips ... On a much larger scale, solar-thermal power plants employ various techniques to concentrate the sun's energy ...

Running a server completely off solar power seems like it would be a relatively easy thing to do: throw up a couple of panels, tack on a charge controller and a beefy battery, and away you go.