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.

Lighting up the dark in off-grid communities

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.

A cooler future, too

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.