Generating solar power at night, it's possible

Solar panels are becoming increasingly prevalent and are being installed on more and more roofs. However, a significant disadvantage of solar panels is that they can only produce energy during the day. Researchers have demonstrated that it is possible to produce solar energy at night, so there is yet hope. Not from sunshine, but from heat that the earth emits from the sun.

Warmth

Infrared light is emitted by all heated bodies, according to researcher Ned Ekins. "Because their body is warmer than the surroundings, you can see someone glowing if you put a thermal camera at them. Similar to this, the Earth emits all of the solar energy it absorbs back into space as infrared." And Ekins and associates have now produced electricity using that energy.

Diode

They accomplish this using a device known as a thermoradiative diode, which is made of the same components as night vision equipment." A semiconductor that can permit some of that radiant energy to pass through is the thermoradiative diode. The thermoradiative diode blocks the flow of energy from the earth that radiates into space, just as a solar cell blocks the passage of energy from the sun to the earth." Ekins emphasizes that this energy flow does originate from the sun; sunlight has already warmed the ground and is then reflected back into space by the earth as infrared radiation.

Thus, some of that infrared light can be absorbed by the diode and transformed into electricity. According to researcher Phoebe Pearce, "The thermoradiative diode generates electricity by giving off infrared light to a colder environment, just as a solar cell makes power by collecting sunlight given off by a very hot sun." "The temperature differential is what enables us to produce energy in both circumstances."

Difference in temperature

Ekins continues, "So the apparatus produces electricity by generating light. The sun is extremely hot, and the earth is hot, but there is also a temperature difference between the earth and space, which is extremely cold. In the case of solar cells, we have the hot sun and a cool solar cell. But the same effect - using other materials - can be used to generate power when a source gives off heat to a cold environment.

Small yield

The thermoradiative diode can produce some electricity, but not nearly as much as conventional solar panels can currently. In fact, the researchers' ability to produce energy using the thermoradiative diode at this point is up to 100,000 times less than what they can with a solar panel. Ekins does, however, believe that a big yield improvement is still possible. Ekins claims that at the moment, the thermoradiative diode can only produce a very little quantity of electricity. "Even identifying that generated electricity was one of our research's hurdles. However, theory predicts that someday it should be possible to give around one-tenth of the energy produced by solar cells."

Combination

Thermoradiative diodes are unable to compete with conventional solar panels due to their low yield. They might be used in conjunction to solar panels, though. "The thermoradiative component might eventually be positioned underneath the solar cell, combining the two technologies. And for a household, a thermoradiative device should be able to produce enough energy in the dark to supply electricity to devices that operate at night, including a freezer and the Wi-Fi router."

Body heat

However, there are additional options. Similar to this, our body heat can also be used as a source of energy. We can produce thermoradiative power "wherever there is a temperature differential," claims Ekins. I'll glow brilliantly in infrared light if you take a thermal image of me because I'm roughly 37 degrees Celsius and everything around me is 20 degrees Celsius. And you may use that temperature difference, for instance, to power a smartwatch. "Our existing thermoradiative diode can already produce enough energy based on body heat to power such a watch if it is scaled up to the size of a watch.

And who knows, perhaps we will create semiconductors that can be incorporated into garments in the future. If so, it might be possible to produce electricity using the infrared light that our clothes emits.

Work in progress

It is futuristic music at this time. It is true that more study needs to be done before far more effective devices that can capture nocturnal solar energy on a much larger scale can replace the thermoradiative diode that researchers have now built as part of their proof of concept. Ekins and colleagues are cautiously hopeful that this technology will have a positive impact in the future, nevertheless. Ekins contends that the thermoradiative diode can assist by supplying energy after the sun has set.

The corporate community will, however, play a significant role in the future. Once the technology is at the point where businesses can profit from selling the product, we anticipate industry to pick up the concept and start aiding in scaling up and lowering costs. Then things can move swiftly, and we believe we can raise revenue by another factor of 10,000. "If the industry recognizes its value, we can start moving forward very quickly."