Powering the World with Renewable Energy is Possible Say Stanford and UC-Davis Researchers Jacobson and Delucchi via What on Earth? at Science Friday Blog

At The Science Friday Blog (Every Day is Science Friday), Neil Wagner uses his comic strip "What on Earth?" in a posting titled
A world of wind power… and solar power…and…
to refer to the research
of Mark Z. Jacobson of Stanford University and Mark A. Delucchi of UC-Davis
which claims that:
"the world could transition to exclusively renewable power sources ... in 40 years or less."

Apparently, the technology is there. Read the whole thing.