Some of our most serious planetary worries revolve around energy and power -- controlling it, paying for it, and the consequences of burning it. Justin Hall-Tipping had an epiphany about energy after seeing footage of a chunk of ice the size of his home state (Connecticut) falling off Antarctica into the ocean, and decided to focus on science to find new forms of energy. A longtime investor, he formed Nanoholdings  to work closely with universities and labs who are studying new forms of nano-scale energy in the four sectors of the energy economy: generation, transmission, storage and conservation.

Nanotech as a field is still very young (the National Science Foundation says it's "at a level of development similar to that of computer technology in the 1950s") and nano-energy in particular holds tremendous promise.

He says: "For the first time in human history, we actually have the ability to pick up an atom and place it the way we want. Some very powerful things can happen when you can do that."