5- THE ARTIFICIAL LEAF
	'Artificial leaf' will convert sunlight into fuel

Enough sheer solar energy strikes the planet's surface every hour to power the world for an entire year, but little of that energy can be stored for later use. Nature found a way around that problem: the humble leaf converts solar energy into storable chemical energy through photosynthesis. So Daniel Nocera — a professor at the Massachusetts Institute of Technology (and a TIME 100 honoree) — took a page from nature, developing an artificial leaf that turns sunlight into chemical fuel. The leaf — a thin silicon solar cell with cheap catalytic materials bonded on both sides — can split water into hydrogen and oxygen when exposed to sunlight, with the gases usable later to power a fuel cell.

The 'artificial leaf,' a device that can harness sunlight to split water into hydrogen and oxygen without needing any external connections, is seen with some real leaves, which also convert the energy of sunlight directly into storable chemical form.

* The earth receives more energy from the Sun in just one hour than the world's population uses in a whole year.
The total solar energy flux intercepted by the earth on any particular day is 4.2 X 10¹⁸ Watt hour or 1.5 X 10²² Joules. This is equivalent to burning 360 billion tons of oil per day or 15 Billion toe per hour. The available solar energy received per year is over 13,000 times the world's consumption per year