As usual, Daniel Nocera came in by the back door.

On a rainy night in April, as the trees on the Boston College campus were sending out their first tentative shoots of spring, Nocera arrived (slightly late) as the keynote speaker for a meeting of the American Physical Society, where he was about to discuss a decidedly inorganic variation on a vernal theme: the “artificial leaf,” his invention that uses sunlight to generate an alternative form of energy.

Life on Earth has converted energy from the sun for at least three billion years, and the sun may be the answer to our energy needs in the future, he begins. He tells the audience that even the food they are starting to digest is unleashing energy from chemical bonds originally forged by the sun.

“To save the planet from the dire consequences of its hydrocarbon addiction, we are going to have to overhaul our entire energy system.”

[READ MORE](http://news.nationalgeographic.com/news/innovators/2014/05/140519-nocera-chemistry-artificial-leaf-solar-renewable-energy/)