A team of researchers from Stanford University may have just redefined the limits of solar energy — by developing a solar panel that can generate electricity at night.
That’s right. A solar panel that doesn’t need sunlight.
Professor Shanhui Fan, leading the groundbreaking research, explains that the new design taps into a natural phenomenon called radiative cooling. It's a process where heat escapes from surfaces into the chilly night sky, particularly during clear nights when infrared energy radiates into space.
This heat loss, it turns out, can be harnessed — and transformed into electricity.
By modifying regular solar panels and attaching thermoelectric generators, the researchers managed to capture this escaping heat and convert it into a small amount of usable energy. While it currently produces only about 50 milliwatts per square meter, a far cry from the 200 watts generated by traditional panels under full sun, it's still enough to power low-energy devices like LEDs and environmental sensors.
It’s a modest output, but Fan believes it’s just the beginning.
This innovation, featured in the recent article ‘First ever solar night panel unveiled to the world: How it works with moonlight’, offers a glimpse into a future where solar panels no longer go to sleep when the sun does.
More than 770 million people worldwide still live without electricity. For many, especially in remote areas, reliable energy is hard to come by — especially at night.
This is where Stanford’s nighttime solar panel could shine.
Because the technology can be retrofitted onto existing solar systems, it opens the door to low-cost upgrades in off-grid locations. The panels could provide critical nighttime lighting or help power small devices without relying on expensive and environmentally harmful batteries.
And since it works best on clear nights — when infrared energy can escape more freely — it may even offer better performance in drier climates where conventional solar can struggle with battery storage.
Radiative cooling isn’t just about nighttime energy. It’s already being used in other sustainable solutions.
One startup, SkyCool Systems, is applying the same principle to create zero-energy air conditioning. Another project at ETH Zurich uses it to harvest clean drinking water in drought-stricken areas.
All of these innovations share a common theme: using ancient principles of physics to solve modern sustainability challenges.
With more research and development, Professor Fan’s invention might soon do more than just extend solar power into the night — it could help bridge the energy gap, reduce battery waste, and make renewable energy systems even more reliable.