Harnessing the sun’s energy during the day for use at night
Researchers at the University of North Carolina (UNC) at Chapel Hill have built a system that converts the sun’s energy not into electricity but into hydrogen fuel. The system then stores this fuel for later use. Chemist Tom Meyer at UNC’s College of Arts and Sciences led the research. He said in a press release on January 14, 2014 that it’s not practical to talk about powering a planet with energy stored in batteries. It’s more reasonable, he said, to store energy in the chemical bonds of molecules. He said:
And that’s what we did – we found an answer through chemistry.
A major hurtle for those trying to develop a viable and inexpensive way to use solar energy has been energy storage. The sun goes down at night, taking with it the ability to power our homes and cars.
Meyer and colleagues at UNC and North Carolina State University used a technique known as a dye-sensitized photoelectrosynthesis cell, or DSPEC, to generate hydrogen fuel by using the sun’s energy to split water into its component parts. After the split, hydrogen is sequestered and stored, while the byproduct, oxygen, is released into the air. But, Meyer said:
… splitting water is extremely difficult to do. You need to take four electrons away from two water molecules, transfer them somewhere else, and make hydrogen, and, once you have done that, keep the hydrogen and oxygen separated.
Meyer’s design has two basic components: a molecule and a nanoparticle. The molecule absorbs sunlight and then kick starts a catalyst to rip electrons away from water. A film of nanoparticles then shuttles the electrons away to make the hydrogen fuel.
The team says the infrastructure to install their new sunlight-to-fuel converters is in sight, based on existing technology.