We are pretty much restricted to the conversion efficiencies of current solar panels (I think 20-something %). However, we can still improvise with this limitation by engineering devices which consume less energy so it can actually fully run under solar energy, like Big K said.
Check out this article at tomshardware. They have a project on running a computer 100% by solar power.
http://www.tomshardware.com/2007/09/..._pc/index.html
By the way einstein, is "electricity" really pollution?
