Store sun's energy during day, power homes at night
Posted on Jan 15 2014 | IANS
New York, Jan 15 : Here comes another possibility of harnessing solar energy during the day for night-time use.
According to a path-breaking study, researchers have built a system that converts the sun's energy not into electricity but hydrogen fuel and stores it for later use - allowing us to power our devices long after the sun goes down.
"So called 'solar fuels' like hydrogen offer a solution to how to store energy for night-time use by taking a cue from natural photosynthesis," said Tom Meyer, Arey distinguished professor of chemistry at the energy frontier research centre at University of North Carolina (UNC) at Chapel Hill.
"Our findings may provide a last major piece of a puzzle for a new way to store the sun's energy - it could be a tipping point for a solar energy future," added Meyer.
The new system, known as dye-sensitised photoelectrosynthesis cell (DSPEC), generates 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, said a UNC report.
Meyer's earlier design had two basic components - a molecule and a nanoparticle.
The molecule absorbed sunlight and then kick-started the catalyst to rip electrons away from water.
The nanoparticle shuttled the electrons away to make the hydrogen fuel.
However, the system always crashed. To solve the problem, Meyer, along with Greg Parsons' group at North Carolina State University, used a technique that coated the nanoparticle with a thin layer of a material called titanium dioxide.
By using ultra-thin layers, the researchers found that the nanoparticle could carry away electrons far more rapidly than before, with the freed electrons available to make hydrogen.
"It turns out that the most practical way to store energy is in the chemical bonds of molecules. And that's what we did - we found an answer through chemistry," concluded Meyer.
In one hour, the sun puts out enough energy to power every vehicle, factory and device on the planet for an entire year.
Solar panels can harness that energy to generate electricity during the day.
Solar energy has long been used as a clean alternative to fossil fuels such as coal and oil, but it could only be harnessed during the day when the sun's rays were strongest.