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There’s a variety of solar panels out there, but the most common ones generate electricity from light. These are usually referred to as photo-voltaic (PV) cells because they work on exposure and physics principles similar in nature to those involved with photography when making pictures using film or digital sensors during imaging processes; another kind generates power by converting thermal energy instead – some examples being concentrators like parabolic troughs that use temperature difference between fluid layers for generating low-grade heat source at high altitudes over deserts where it’s sunny all day long!

When the sun is hotter and Earth cooler, that difference in temperature can be converted into usable energy.

That second kind of solar panel is what inspired researchers at Stanford University in Palo Alto, California to develop a new system that can harness energy during nighttime. It’s based on the concept using heat as an alternative power source but with some key differences from traditional generating methods such like being inverted so it has warmer side facing outwards instead going through whatever cold-wasps may be flying around these days!

Air conditioners use the heat difference between night-time coolness and a warmer Earth as an energy source. The study has been published in Joule magazine.”

Study author Shanhui Fan, Stanford electrical engineering professor, told Gizmodo:

The amount of power coming in from the Sun has to be approximately equal to the amount going out from the Earth as thermal radiation, in order to keep the Earth at a roughly constant temperature. The amount of power available for harvesting is very large.

Dubbed an “anti-solar panel” by some, the device has the potential to bridge a gap left behind in solar energy. It harnesses nighttime sky and outer space for power with its thermoelectric generator based on cold nights versus warm days or hot summers which generates cheap electricity from wasted heat!

The researchers write:

We use a passive cooling mechanism known as radiative sky cooling to maintain the cold side of a thermoelectric generator several degrees below ambient. The surrounding air heats the warm side of the thermoelectric generator, with the ensuing temperature difference converted into usable electricity. We highlight pathways to improving performance from a demonstrated 25 mW/m2 to 0.5 W/m2. Finally, we demonstrate that even with the low-cost implementation demonstration here, enough power is produced to light a LED: generating light from darkness.

The researchers have only tested their system with a very small prototype. The device was an aluminum disk painted black and hooked up to commercial thermoelectricity generators, which successfully created enough energy to power one LED lightbulb—a step in the right direction with immeasurably massive potential!

As ScienceNews reports:

A bigger version of this nighttime generator could someday light rooms, charge phones or power other electronics in remote or low-resource areas that lack electricity at night when solar panels don’t work.

It’s clear that this is still in the research stage, but it may be able to come close with future improvements. Right now they’re working on an improved insulation around top plate which could potentially produce up 0.5 watts per square meter or more!

The potential for this new technology is massive. It could completely transform how we generate and use energy, not only in the renewable sector but also across industries like transportation or homes with inefficient heating systems that need to rely on fossil fuels year-round.


A team at ETH Zurich has been working tirelessly over several years developing a system which takes advantage of natural sunlight as an inexpensive form of power by using highly efficient concentrating optics lenses—the same type used daily when you drive your car’s eyeglasses! With their work complete now they’ve handed off prototypes into production where first units are expected towards end next year.