Nighttime Solar: Reverse Panels Generate Power After Dark

Researchers at the University of New South Wales (UNSW) in Australia are advancing a groundbreaking technology known as thermoradiative diodes, often described as reverse solar panels. These devices produce electricity at night by exploiting radiative cooling, a natural process where Earth releases heat absorbed during the day as infrared radiation into the cold expanse of space.

Traditional solar panels rely on photovoltaic cells to convert sunlight into electricity and remain inactive after sunset. In contrast, thermoradiative diodes operate in reverse: they emit infrared photons from a warmer surface (the panel) toward a colder environment (the night sky), generating a small electric current through this heat differential. The concept draws from earlier theoretical and modeling work at institutions such as Harvard and Stanford University.

In 2022, UNSW researchers became the first to experimentally demonstrate direct electrical power generation using this approach. Current prototypes yield very modest output—approximately 100,000 times less than conventional solar panels—making them unsuitable for large-scale grid applications at present. However, the technology shows promise for low-power needs.

Professor Ned Ekins-Daukes, leading the UNSW effort, explains that Earth continuously radiates heat outward at night, visible as a glow on infrared cameras. This steady emission creates an opportunity to harvest energy without sunlight. Potential uses include powering small overnight loads, such as WiFi routers or phone chargers, thereby reducing reliance on batteries. A particularly compelling application lies in space: satellites, which alternate between sunlit and dark phases roughly every 45 minutes, could use these diodes to maintain operations during orbital night when temperatures drop dramatically.

While efficiency remains low, ongoing improvements aim to enhance output and practicality. This innovation represents a step toward more continuous renewable energy generation, complementing daytime solar systems and addressing intermittency challenges.

Key Takeaways

1. Thermoradiative diodes function as reverse solar panels, generating electricity at night by radiating infrared heat into space via radiative cooling.

2. UNSW researchers achieved the first direct demonstration of power output in 2022, though current levels are significantly lower than traditional photovoltaic panels.

3. Future applications focus on low-power devices (e.g., overnight electronics) and satellite power during dark orbital periods, with potential to extend renewable energy availability.

Original source: Scientists Pioneer Reverse Solar Panels to Create Energy at Night on OilPrice.com.

Doesn't sound like they will work here.

2 minutes ago, unblocktheplanet said:

Doesn't sound like they will work here.

Why is that? Because things don't get hot during the day here?

Remember that the first solar panels were highly inefficient - only about 1-2% of the solar radiation was converted into electrical energy.

So give it time, and hopefully this new technology will become more efficient :)

18 hours ago, GroveHillWanderer said:

Why is that? Because things don't get hot during the day here?

You likely have a better understanding of engineering principles than I. Doesn't really sound like they can power aircons.