Australia’s prolific rooftop solar panels could soon be gathering power overnight, following innovative research showing Earth’s radiant heat can be used to generate electricity, even after the sun has set.
UNSW researchers have made a major breakthrough in renewable energy technology by producing electricity from so-called ‘night-time’ solar power.
The team from the School of Photovoltaic and Renewable Energy Engineering generated electricity from heat radiated as infrared light, in the same way as the Earth cools by radiating into space at night.
In the experiment, a semiconductor device called a thermoradiative diode, composed of materials found in night-vision goggles, was used to generate power from the emission of infrared light.
Although the amount of power generated at this stage is very small – around 100,000 times less than that supplied by a solar panel – the researchers believe the result can be improved in the future.
A/Prof Ekins-Daukes says the process is ultimately still harnessing solar power, which hits the Earth during the day in the form of sunlight and warms up the planet.
At night, this same energy radiates back into the vast, cold void of outer space in the form of infrared light. The thermoradiative diode has now been shown to be able to generate electricity by taking advantage of this process.
“Whenever there is a flow of energy, we can convert it between different forms,” Ekins-Daukes said.
“That first silicon solar cell was only around 2% efficient, but now modern-day cells are able to convert around 23% of the sun’s light into electricity.”
Dr Michael Nielsen, co-author of the paper, believes the new technology could have a range of uses in the future by helping to produce electricity in ways not currently possible.
“By leveraging our knowledge of how to design and optimise solar cells and borrowing materials from the existing mid-infrared photodetector community, we hope for rapid progress towards delivering the dream of solar power at night”, Nielsen said.
“If industry can see this is a valuable technology for them, then progress can be extremely fast”, he concluded.
