This Google owned company could be on the way to mass producing cheap solar collectors.  Cheap clean energy is a top priority for humanity right now.

Nanosolar Inc. claims to have broken several barriers to ubiquitous solar energy.  Their manufacturing process consists of printing nano-scaled solar-cell layers, bypassing the traditionally expensive vacuum methods yet meeting and in some cases, exceeding industry standards.  Major claims include a 3 week payback time and lightweight flexible panels.