Words by Smiley Team
Solar panels need sunlight to operate right? Wrong. For the first time, solar panels are able to do the seemingly impossible - generate electricity at night.
The eureka moment unfolded in the engineering department of Stanford University, where researchers have developed a remarkable adaption for solar cells.
Rather than just depending on energy from the sun’s rays, the cells can also generate electricity from dissipating heat at night.
For this to be possible, an electrical engineer and physicist, Shanhui Fan, and his team added a thermoelectric generator to the cells. The attached device uses temperature differences to generate electrical currents.
“The solar panel turned out to be a very efficient thermal radiator,” Shanhui told New Scientist.
“So, at night, the solar panel can actually reach a temperature that’s below the ambient air temperature, and that’s a rather unusual opportunity for power harvesting,” he explained.
The discovery completely remodels the standard solar panel produced with a semiconducting material that only generates electricity when absorbing the sun’s energy. This puts traditional panels at a great disadvantage because they cannot operate in darkness.
However, this weakness has proven useful. In the midst of the night, they lose heat, reducing their temperature to well below that of the air. It’s this change in temperature that allowed the engineers to produce extra electricity.
The exact quantity of electricity is a small fraction of what the panels can produce in a day. But with an output of 50 milliwatts per square metre, it’s just enough to power an LED light, a phone charger or other small, low-energy consuming devices.
Nearly a billion people around the world still lack electricity in their homes. While electrical power is such a scarce resource and fossil fuel extraction hikes up global emissions, innovations such as these could offer a means to uplift communities.
Inspired to act?
VOLUNTEER: If you’re interested in helping to build renewable energy for communities in London, volunteer for renewable energy charity Repowering.
GO GREEN: To install solar panels yourself in the UK, find out how you might be able to do so with the help of non-profit Solarsense.