The Sahara Desert has two things in abundance: sun and sand. What if they could be used symbiotically to eventually provide half the world's energy?
Here's the plan: Build manufacturing plants around the Sahara Desert that will extract the silica from the plentiful sand, and use it to make photovoltaic solar panels. The first solar panels, in turn, will be used to build some initial solar power plants, the energy from which will be used to power more silicon manufacturing plants—or to "breed" more solar power plants—which will provide more clean energy to manufacture more PV panels, which can power more silicon plants, and on and on and on. Until, eventually, there are enough solar power plants in the Sahara to churn out enough photovoltaic panels to provide half the world's electricity needs by 2050.
This video from Diginfo TV further explains the project:
[youtube]http://www.youtube.com/watch?v=UdO6T1TIDzQ
A quick caveat: Some have been reporting that the solar power plants in the Sahara alone would be providing half the world's energy needs. From what I can tell, this isn't the case. The project's lead scientist, Hideomi Koinuma from the University of Tokyo, who is calling this project the "Super Apollo Project," anticipates 100 Gigawatts worth of solar energy from these Saharan plants, which isn't even close to half of global demand. It's still nothing to sneeze at, though, and would be over 50 times as productive as the massive Aswan High Dam that provides power to much of Egypt. A vast network of supercooled high-voltage direct current grids would could transport the juice over 300 miles. The plants themselves, I assume, would be producing enough photovoltaic panels themselves to provide clean, renewable solar power to cover half the world's demand. (If all goes to plan. A huge if.)
But if this can be accomplished, and a single solar plant can be built in the Sahara, then the process can almost certainly be scaled up. Koinuma, for one, is optimistic.