‘Anti-solar panel’ concept generates power in the dark

Solar panels harness the photovoltaic effect to generate electricity. They absorb packets of light (photons) from the Sun, causing electrons to become excited and flow within the module, generating a current. Surplus power generated during periods of intense sunlight is stored in batteries for use at other times, although battery technology has advanced relatively slowly.

Professor Jeremy Munday, an electrical engineer at the University of California, Davis, has laid out proposals for a “night-time photovoltaic cell” in ACS Photonics, which would use the Earth as a heat source and the sky as a heat sink into which the device releases infrared radiation (light of a lower frequency than visible light).

While the concept has been compared in statements to a solar panel, it does not use a similar process and is essentially a heat engine.

“A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow,” Munday explained. “In these new devices, light is instead emitted and the current and voltage go in the opposite direction, but you still generate power. You have to use different materials, but the physics is the same.”

Munday’s prototype produces 50W per square metre, while conventional solar panels produce approximately 200W per square metre during daytime.

Munday told CNN that the concept device has a clear advantage over conventional solar panels, which can only work during the day: “Nobody wants to lose power once the Sun sets,” he said.

He suggested that the devices could run on excess heat generated from industrial processes, as well as potentially being incorporated into domestic buildings like conventional solar panels.