According to professor Brian Cox in Wonders of the Solar System, the sun produces more energy in a second than 1 million times the power used by the US in an entire year. Cleverly, Markus Kayser has found a way of making things out of it.
His ‘Solar Sinter‘ project uses similar principles of the rapid prototyping technique in which powdered plastics and metals are melted together very precisely by a laser to form an accurate physical counterpart of a digital model. Markus however is melting sand into glass with concentrated sunlight.
It produces some pretty impressive results. With further development you can imagine it possible to form building components for much larger structures at no cost to the environment just by downloading the relevant model files.