While the price of solar power has been falling dramatically, its big disadvantage remains its intermittency. When the sun don’t shine, you’re stuck looking for something to take its place. Which is why the ability to turn solar energy into another usable form--like hydrogen--is potentially so important.
That’s what Daniel Nocera is doing in his lab at Harvard. Take a look at this video. What you’re watching is an "artificial leaf": a piece of silicon (a solar cell) coated with two catalysts. When sunlight shines in, the leaf splits the water into bubbles of hydrogen and oxygen on each side. At scale, the device could provide a super-cheap and storable energy source from the sun; the hydrogen would be piped off and used in a fuel cell to make electricity.
Nocera and his team first announced the technology back in 2011, while the chemist was still at MIT. He’s now published a follow-up paper, showing how the team has improved the leaf’s efficiency, and laying out future challenges, and how these might be overcome.
The researchers now plan a field trial, with the eventual aim of building a commercial device for the developing world. Nocera’s company, Massachusetts-based Sun Catalytix, is commercializing the technology, and has received funding from ARPA-E, among others. His dream, he says, is to provide the poor with "their first 100 watts of energy."
There have been previous attempts to generate hydrogen from sunlight and water. But the materials involved were seen as too expensive, and the devices unstable. Hopefully, Nocera’s template will prove more long-lasting.